# MT3 vs R8 spindle taper



## Eyecon (Nov 25, 2022)

Hello Friends,
So things escalated quickly today and I went from wondering about a cx605 mill to ordering a PM-25MV clone from a local eBay seller. Initially I could find the MT3 spindle taper version but after contacting the seller they said they can get the R8 version by mid December. Soon after placing the order, seller told me it would actually take much longer and I’d have to wait until mid Feb due pandemic related delays in China. Regardless of the intent/backstory, the MT3 version is supposedly in stock in Canada. I know Morse taper is really designed as a self holding taper so might be annoying to take out tools or holders each time. Opinions? Do I wait for the R8 in 3 months or go for the MT3?


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## Crankit (Nov 25, 2022)

I would suggest having a look around at the availability of MT3 tooling, I was looking at a decent small mill a few years ago which was using MT3 and there wasn't a lot around at the time. R8 is night and day difference, personally I would wait for that R8 model.

Cheers,

Wayne


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## David_R8 (Nov 25, 2022)

I have MT 3 taper on my mill and have no problem getting tooling. I use an ER32 collet chuck on a MT3 arbor, and I have an MT3 collet which I use with TTS-style tool holders. I bought a straight shank Criterion boring head and a straight shank face mill which I use with the MT3 collet.


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## Eyecon (Nov 25, 2022)

David_R8 said:


> I have MT 3 taper on my mill and have no problem getting tooling. I use an ER32 collet chuck on a MT3 arbor, and I have an MT3 collet which I use with TTS-style tool holders. I bought a straight shank Criterion boring head and a straight shank face mill which I use with the MT3 collet.


Very interesting, my primary use would be with an ER collect chuck as I already have the collets and an mt3-er32 that I use on my lathe. I want to be able to quickly switch between the er collet(s) and my Haimer for which I was hoping to have a fixed tool holder(TTS style or something similar). Do you have any issues with MT3 getting stuck? Also would you mind sharing some details about the MT3 collet to TTS style holders? The reason I’m interested in a fixed tool length holder is because of the eventual CNC conversion. I’d really like to avoid having to probe tool length each time if I don’t have to(unfortunately I currently have to do so in my ER20 routers)


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## Degen (Nov 25, 2022)

R8 as it has a spline to prevent rotation, depending on the CNC configuration this interface will become your weak link.  As an example 1/2" endmill full width cut 0.050 depth at 20IPM puts a lot of load on everything.


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## Susquatch (Nov 25, 2022)

Eyecon said:


> Do I wait for the R8 in 3 months or go for the MT3?



I'd wait for the R8. I have an MT3 in my big Mill Drill. It does the job. Still LOTS of tooling options out there. I have an R8 in my knee mill. I like it better! You can't really depend on the index pin in it to stop rotation. That should be done by achieving the correct torque. Lots of R8s out there with broken pins. Torque it correctly and it won't happen - knock on wood......

I think the big difference is that R8 is a near self releasing taper vs MT3 - way less thumping. Much easier on the spindle and much easier on the machinist. Mine certainly is....

Supposedly R8 is also more precise. Or so they say. I don't believe it. Perhaps it's just that as you move up the food chain there is more R8 than MT3.

Edit - the pins on most R8 spindles is usually easy to replace so don't let that scare you. Better to have it than not.


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## Susquatch (Nov 25, 2022)

Eyecon said:


> Soon after placing the order, seller told me it would actually take much longer and I’d have to wait until mid Feb due pandemic related delays in China. Regardless of the intent/backstory, the



Frankly, this scares me. Although all this stuff comes from China today, the shifting sellers story gives me the creeps. 

Some folks on here would say skip the middle man and buy direct from China. 

Others would say go to a higher line re-seller like Precision Mathews. 

Still others would say buy from Busy Bee, King, or Grizzly. 

My own preference would be to buy a good used one. 

Regardless, we are all interested in following how your buy goes. Please keep us informed.


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## 6.5 Fan (Nov 25, 2022)

You already have some MT3 tooling that is used on the lathe, so i would go that route. I have MT3 on the lathe and mill they sit close to one another and i use the same tooling on both machines. Just my point of view, less stuff to buy, spend more on cutters.


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## Eyecon (Nov 25, 2022)

Susquatch said:


> Frankly, this scares me. Although all this stuff comes from China today, the shifting sellers story gives me the creeps.
> 
> Some folks on here would say skip the middle man and buy direct from China.
> 
> ...


I would go with a PM If they had presence in Canada. The idea of paying 400-500 dollars in shipping and some ridiculous customs clearing fees and dealing with all that from US or China is what led me to look at the Craftex cx605 in the first place and then this eBay seller offering free shipping. I’ll take a look at what King has.


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## Eyecon (Nov 25, 2022)

Thanks everyone for the replies. So the  only similarly sized/spec’d option in Canada that I could find that doesn’t cost too much to ship is a king PM25 clone from KMS tools. It’s R8 but geared spindle and brushed single phase AC…maybe the motor is not an issue but I’d rather have a less popular taper than gears that are potentially plastic. Open to other suggestions but it looks like i may go with the in stock mt3 version from that eBay seller as it’s also about 350 cad cheaper not including the tax reduction.


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## Degen (Nov 25, 2022)

In all my years if using an R8 I've never broken the pin (knock on wood)  but I also torque the draw bar correctly as @Susquatch recommends.

I have spun a MT on an occasion or two.


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## Eyecon (Nov 25, 2022)

Degen said:


> In all my years if using an R8 I've never broken the pin (knock on wood)  but I also torque the draw bar correctly as @Susquatch recommends.
> 
> I have spun a MT on an occasion or two.


I’m honestly not sure the r8 spindle configuration on this clone even takes pins. I get the point of course


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## Susquatch (Nov 25, 2022)

6.5 Fan said:


> You already have some MT3 tooling that is used on the lathe, so i would go that route. I have MT3 on the lathe and mill they sit close to one another and i use the same tooling on both machines. Just my point of view, less stuff to buy, spend more on cutters.



This is an absolutely excellent point. Tooling cost is almost always more than the machine cost for most of us. Might also provide some redundancy as both prolly come with a drill chuck. One will probably be better than the other. Heck you might even find yourself swapping! 

If you go this way, keep an eye on the drawbar thread when you order stuff. The MT3 drawbar thread is not always the same on all MT3 tooling. This has caught me a few times and then I had to deal with the return hassle. I prolly should have just made another drawbar.


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## Eyecon (Nov 25, 2022)

Yes lm almost 100% the mt3 will be a metric M12 drawbar vs 3/8-16 which I guess is standard for MT3 in North America. I’m also finding native Mt3 tools like boring heads, face mills, fly cutters in MT3 and they cost the same as the R8 versions. Also collets on MT3 almost cost the same as R8 although there might be slight more buying options for R8. I understand the slippage concern but l doubt this cheap clone will have a keyed R8 spindle so I’m not really seeing the point. TTS exists for both R8 and MT3 as well which could be a plus for fixed tool size cnc setup. Also I don’t believe the power drawbar mechanism for either type of spindle will be any different.

 Again, I’m super new to this but it feels like it the MT3 options will be equally good especially that I can take delivery sooner and save 400 cad in price difference and tax


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## Eyecon (Nov 25, 2022)

One last thing I should mention is that I pan to mainly use ER collets at the beginning to share tools and collets with my CNC routers…other the figure out the Haimer situation, I’m not really planning on using the drawbar for tool changes unless I make a dedicated mount for the Haimer vs chucking it in the er20 or er32 collets


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## Susquatch (Nov 25, 2022)

Eyecon said:


> I understand the slippage concern but l doubt this cheap clone will have a keyed R8 spindle so I’m not really seeing the point.



I'd bet big bucks it does. The only ones I've ever seen that didn't were actually broken, not missing.

I don't think the main purpose of the pin is to stop slippage. That is the job of the taper. If you torque it properly, the pin shouldn't be required and shouldn't be breaking either.

I think the pin is mostly there to hold the adapter while you tighten the drawbar. It's way easier than putting your finger in there to hold it. I've also seen a few people spin the taper in instead of turning the drawbar. Not a practice that I recommend. Of course, once the taper engages, it's not an issue anymore.

FWIW, I like the pin.


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## Eyecon (Nov 25, 2022)

Oh I see, that’s very interesting and at least given the price difference and wait time maybe make me feel a little better about the mt3 version. Like I said I’m very new to the world of small mills but given what everyone said and what’s available in terms of Asian tools, it feels like I should really save the money and go with the in-stock mt3 version.


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## phaxtris (Nov 25, 2022)

Just a thought, but if you go r8 all of your tooling will swap over to your next larger mill


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## David_R8 (Nov 25, 2022)

Eyecon said:


> Very interesting, my primary use would be with an ER collect chuck as I already have the collets and an mt3-er32 that I use on my lathe. I want to be able to quickly switch between the er collet(s) and my Haimer for which I was hoping to have a fixed tool holder(TTS style or something similar). Do you have any issues with MT3 getting stuck? Also would you mind sharing some details about the MT3 collet to TTS style holders? The reason I’m interested in a fixed tool length holder is because of the eventual CNC conversion. I’d really like to avoid having to probe tool length each time if I don’t have to(unfortunately I currently have to do so in my ER20 routers)


I have never had the MT3 collet get stuck or be hard to remove.
The TTS holders are just as they are sold with a 3/4" straight shank. They slip right into my 3/4" collet no problem.


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## Eyecon (Nov 25, 2022)

phaxtris said:


> Just a thought, but if you go r8 all of your tooling will swap over to your next larger mill


I think if I go larger it will be a VMC with bt or iso tappers. I really do appreciate the advice but I don’t want to wait  3 months( basically also have 2700 CAD on hold) to get started on an entry level mill because of the spindle taper. I also hope that if I really want to, I’d find the R8 spindle arbor and bearings do the replacement if I absolutely regret the mt3


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## Eyecon (Nov 25, 2022)

David_R8 said:


> I have never had the MT3 collet get stuck or be hard to remove.
> The TTS holders are just as they are sold with a 3/4" straight shank. They slip right into my 3/4" collet no problem.


Very good to know and I appreciate the confirmation. I really do appreciate everyone’s advice and I totally understand that R8 is more popular in North America where as MT is more common in Europe. From a bit of research and from all the comments here I don’t think it will make that much difference for my use case even for a power drawbar setup or native spindle taper tooling. @David_R8 I found a couple of options for boring heads and facemills in MT3 on Amazon.ca  so I’m not too concerned with tooling options. I think I’ll have to make a couple of draw bars to work with the different standards but other than that and again for my specific use case, I have a feeling MT3 will be just fine.


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## Degen (Nov 25, 2022)

Sigh....sorry I have to write this....

OMG OMG no pin, pin broken, what am I to do????? Take it to a machinist to fix it.....W A I T!!! (Insert your won name here) I am a machinist, problem solved.

You guys so funny.


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## jcdammeyer (Nov 25, 2022)

I turned my Craftsman floor standing drill press into a mill press by having a friend use his lathe to bore the spindle for 5/16" shafting.  To make sure the drill press would survive I bought a spare spindle from Sears before he started.  The drill press has MT3 tooling which consists of a few holders 3/8", 1/2, 5/8" and 3/4".  Along with that a couple of stub arbors and a boring head with MT3 shaft.  I used it principally for milling aluminum castings for my Gingery Lathe.  Don't think I ever used the boring head.

Once I bought my mill with R8 tooling I did buy an MT3-R8 holder. extends about 1.25" below the bottom of the spindle.  And then the MT3 would fit into that.  Not sure why I bought it or the MT2-R8 adapter.  Haven't used either.

Key thing to remember, especially with a small mill is that you don't have a huge amount of height from spindle to table.  Especially once you add a vise.  Wasn't an issue with the floor standing drill press.

Using R8 with the flattened 3/4" (19mm) TTS collet means the R8 tooling doesn't protrude far.  For that matter although you want to go CNC eventually, R8 collets holding say a 1/4" mill also means you get maximum distance from tool tip to table.  Your MT3 tooling won't give you that.  You automatically lose about 1.25" or more with the holder. 

Here's the drill press.  Although not measured there is not a large distance between the end of the fairly small diameter spindle and the back of the drill chuck.  But add in the tool holder like in the next picture and that subtracts from milling height.




 So here's the R8 to MT3 adapter holding a 3/8" MT3 milling cutter holder and a ball mill.  It's at the 5" mark that the R8 taper begins.   Even if the spindle on the mill only protrudes 3/4" from the quill of the milling machine you still have 2.5" + 0.75" = 3.25" sticking out.  Compared to fitting that 3/8" ball mill directly into a collet.  I can take a picture of that to show the difference after I get back from doggy walk.


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## Eyecon (Nov 25, 2022)

jcdammeyer said:


> I turned my Craftsman floor standing drill press into a mill press by having a friend use his lathe to bore the spindle for 5/16" shafting.  To make sure the drill press would survive I bought a spare spindle from Sears before he started.  The drill press has MT3 tooling which consists of a few holders 3/8", 1/2, 5/8" and 3/4".  Along with that a couple of stub arbors and a boring head with MT3 shaft.  I used it principally for milling aluminum castings for my Gingery Lathe.  Don't think I ever used the boring head.
> 
> Once I bought my mill with R8 tooling I did buy an MT3-R8 holder. extends about 1.25" below the bottom of the spindle.  And then the MT3 would fit into that.  Not sure why I bought it or the MT2-R8 adapter.  Haven't used either.
> 
> ...


Wow I really appreciate the detailed explanation!  I’m not sure I understand why the MT3 collets would extrude any further than the R8. Say for examples using something like this:









						Collet Set, 3MT, Set of 4 2023
					

Morse Taper Collets 2023 Set of four #3 Morse taper round collets; 3/8"-16 internal drawbar thread; Made of high grade tool steel; Hardened and ground...




					littlemachineshop.com
				




With a “quick release” sort of setup with TTS or even just custom straight shaft holders the stick out would be the same because the collets (either the R8 or MT3) need to be a little shorter than the spindle bore so that the holder registers against the spindle

Again I’m a total newbie here but just going with what I’ve seen others do such as this:


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## jcdammeyer (Nov 25, 2022)

There are times, perhaps not very often, where you need that extra space.




The R8 holding the tool I stead of a TTS collet holder or even 3/8" tool holder is all longer and perhaps makes that one operation impossible.

So given the opportunity I'd rather have R8 all other things being equal.

I can take a photo of a TTS 3/8" holder with the ball mill for comparison.


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## jcdammeyer (Nov 25, 2022)

And yes.  With those MT3 holders you het the same advantage.

I think, but haven't checked, that MT3 spindles can have smaller diameter spindles and bearings.  I believe bigger is better?


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## Eyecon (Nov 25, 2022)

jcdammeyer said:


> And yes.  With those MT3 holders you het the same advantage.
> 
> I think, but haven't checked, that MT3 spindles can have smaller diameter spindles and bearings.  I believe bigger is better?


Yeah this probably true but given the price point I doubt the difference is anything but the end of the spindle shaft…I cant see an Asian budget manufacturer machining the same castings in two different ways for larger  bearings or shaft…of-course I could be totally wrong. But I think I’m going to go for the MT3 one that’s in stock rather than wait for 3 months and have the machine get stuck in China due pandemic lockdowns(which is why the seller is telling me the R8 version is going to get to Canada in Feb23)


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## jcdammeyer (Nov 25, 2022)

Here's a TTS holder for 3/8" end mill.  The advantage of the TTS costs about 1.75" in milling height.




Now if I hold a 3/8" cutter in an ER32 collet then I lose another 0.5" or so.




And of course the R8 collet lets go with about 3/4 turn on the draw bar and gentle tap.

Not trying to convince you one way or the other.  Just so you know.  I'd try and get some measurements on spindle bottom to table distances on both R8 and MT3.  Losing 0.5" to 1" of milling height doesn't sound like much until it happens on a regular basis.

John


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## Eyecon (Nov 25, 2022)

jcdammeyer said:


> Here's a TTS holder for 3/8" end mill.  The advantage of the TTS costs about 1.75" in mil
> Now if I hold a 3/8" cutter in an ER32 collet then I lose another 0.5" or so.
> View attachment 28262
> And of course the R8 collet lets go with about 3/4 turn on the draw bar and gentle tap.
> ...


Thank you so much for taking the time to take pictures and provide additional information. Just to make sure I’m tracking: holder #3 from above is TTS in R8 while the er32 collet is in an MT3? I’m still not sure I understand the advantage of R8 over MT3 in terms od Z height. This is actually a very important aspect for me since it’s something I really suffer from on the CNC routers. Again appreciate your help and patience in explaining this to me


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## jcdammeyer (Nov 25, 2022)

If you have a 19mm or 3/4" collet in your MT3 spindle the TTS will have to bear up against the base of the quill in order to properly register.  So all the photos except for the first one were R8 on my mill.
Now look closely at the first photo which is the craftsman drill press that I modified to have a draw bar.
I don't have a 3/4" MT3 collet to try but it's unlikely TTS tooling would properly bear up against the bottom of the quill.   I'll go measure some diameters and report back.

And there's no such thing as a dumb question.


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## Eyecon (Nov 25, 2022)

Oh I see what you are saying now.  I found this picture  from a 2015 article of someone who got a mill with the MT3(https://longezproject.blogspot.com/2015/03/cnc-mill-conversion-part-23.html?m=1). So if I understand the concept of TTS, it has to register against the quill otherwise it’s not doing what’s it’s supposed to do, this is independent of the spindle taper as long as you find a way for the spindle to hold a 3/4” shaft, which the MT 3 can do just like the R8


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## jcdammeyer (Nov 25, 2022)

So busybee sells a MT3 collet set good to 3/4".








						COLLET SET MT3 11 PC
					

These collets are very useful when the distance between machine-table and spindle is limited.




					www.busybeetools.com
				



The OD of the spindle on my drill press is 34mm while the outside of a TTS holder is 36mm.  There's still just enough of flange that I can touch the spindle.  The question would be how far would the 3/4" MT3 collet protrude and would it prevent mating the back of the TTS holder with the face of the spindle.
I believe MT3 is right on the edge of working for TTS.


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## jcdammeyer (Nov 25, 2022)

Eyecon said:


> Oh I see what you are saying now.  I found this picture  from a 2015 article of someone who got a mill with the MT3(https://longezproject.blogspot.com/2015/03/cnc-mill-conversion-part-23.html?m=1)


Ah.  So on that little mill the quill is just a tad larger diameter and seats the TTS completely .  And clearly the 3/4" collet doesn't interfere with the inner part of the TTS tool.

I've been told that heavy cuts with 3/4" mills in steel in R8 holders is pushing their limitation.  The tool may still turn in the R8 collet.  It's the danger you face with either the MT3 collet turning or the TTS turning in the 3/4" (19mm) collet.  

The solution is really simple.  Don't take heavy cuts.  As you are intending to go CNC anyway, or at at least adding power feed to say X axis, the dull and uninteresting part of hand cranking small cuts over and over again vanishes.  A few lines of G-Code, start it up, go and grab a coffee and sit and watch or do something else while it's removing 1" of steel out of a 2"x 3" pocket.


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## Eyecon (Nov 25, 2022)

jcdammeyer said:


> So busybee sells a MT3 collet set good to 3/4".
> 
> 
> 
> ...


Based on the information I found on both the tormach and LMS sites, TTS require modified Collets for both spindle tapers: R8 flat like you said and a slightly shorter collet in the case of MT3 so the collets are not interfering  with what the TTS needs to do. I also think the groove in the TTS flange is specifically so that slightly longer or inaccurate length of the native collets(R8 or MT3) doesn’t prevent the holder from registering.

So I’d either need to buy this: https://tormach.com/tts-collet-mt3-30251.html
Or
Buy and machine down this: https://www.busybeetools.com/products/collet-mt3-3-4in.html
And since my lathe spindle is MT3 all I need to do is stick it in the spindle without a chuck and face it off by however much is needed to make the tts holder flush. 

In any case a ready made solution is available and costs the same as the R8 version…unless I’m missing anything


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## jcdammeyer (Nov 25, 2022)

Oh and in the photo above where you see the #3 on the cutter holder.  That's tool table entry #3.  So when I do a tool change the length of that tool is factored into the Z zero position so when I change from tool #4 to tool #3 the system knows where the edge of the cutter is.


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## Eyecon (Nov 25, 2022)

jcdammeyer said:


> Oh and in the photo above where you see the #3 on the cutter holder.  That's tool table entry #3.  So when I do a tool change the length of that tool is factored into the Z zero position so when I change from tool #4 to tool #3 the system knows where the edge of the cutter is.


Very nice. That would be the plan for the mill. I’ll use my Haimer in a probe TTS holder to set Z, then have all my tool heights programmed in linuxcnc. With my routers I do the same but because I’m using er20, I have to set each tool height against a tool setter before each op which is still very annoying even with 400ipm rapids


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## jcdammeyer (Nov 25, 2022)

Eyecon said:


> Based on the information I found on both the tormach and LMS sites, TTS require modified Collets for both spindle tapers: R8 flat like you said and a slightly shorter collet in the case of MT3 so the collets are not interfering  with what the TTS needs to do. I also think the groove in the TTS flange is specifically so that slightly longer or inaccurate length of the native collets(R8 or MT3) doesn’t prevent the holder from registering.
> 
> So I’d either need to buy this: https://tormach.com/tts-collet-mt3-30251.html
> Or
> ...


BusyBee is out of stock but yes.  Stick the collet in the lathe holding a piece of 3/4" Stock just barely protruding.  Face them both.  Likely the collet is hardened so you will need carbide.

Now all you are left with is the ease of releasing the collet enough so the TTS drops out.  That's simple triganometry.  To let the collet expand in the horizontal direction Y it needs to move down in the Y direction following the hypotenuse of the collet angle.   The R8 has a much sharper angle so will have to move less than the MT3.


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## jcdammeyer (Nov 25, 2022)

Eyecon said:


> Very nice. That would be the plan for the mill. I’ll use my Haimer in a probe TTS holder to set Z, then have all my tool heights programmed in linuxcnc. With my routers I do the same but because I’m using er20, I have to set each tool height against a tool setter before each op which is still very annoying even with 400ipm rapids


I have on order one of these higher end tool setters. 





Apparently it's left the country (China) so won't be hung up in the lock downs.  Now the goal will be to touch the surface of the spindle to it to determine 0.  Then each tool to it to calculate tool length and enter into the table.  

Then use my probe to find the 0 position of the work held in the vice or clamped to the table.




This is also held in a TTS holder so I can also use the touch plate to determine the length of it.  Eventually I'll have this all functioning so it's simple enough to remember and use without spending time figuring out what I forgot from a month ago.


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## jcdammeyer (Nov 25, 2022)

I plan on using the same input for the tool height setter as for the probe.  Should be interesting determining the length of the probe since it will likely move up while the touch plate on the tool setter moves down.  Haven't quite figured out how I'll deal with that but then this is now a bit off topic for your original question.


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## Eyecon (Nov 25, 2022)

jcdammeyer said:


> I plan on using the same input for the tool height setter as for the probe.  Should be interesting determining the length of the probe since it will likely move up while the touch plate on the tool setter moves down.  Haven't quite figured out how I'll deal with that but then this is now a bit off topic for your original question.
> View attachment 28267


Do you have a dial or digital tool setter? The process would be to set the probe against the reference ground surfaces of the setter and then move the quill to and down on to the “plunger” of the setter until it reads zero. The tool setter is obviously zeroed relative to the reference ground surfaces(using a gage or 123 block) The difference between the machine absolute position when the probe triggered vs when the quill reached zero on the setter is the exact height of your probe trigger point relative to the quill(which is your WCS reference for tool heights and probe height in Z)


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## Eyecon (Nov 25, 2022)

You can also rig up a dial indicator and a 123 block to do the same. Feel free to PM if you need detailed help.


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## jcdammeyer (Nov 25, 2022)

Eyecon said:


> You can also rig up a dial indicator and a 123 block to do the same. Feel free to PM if you need detailed help.


Haven't received the tool setter yet.  Supposed to arrive Jan 4th.  I suspect it will be sooner but it's currently in limbo here which is code for it's now on a container on a boat headed your way...






Eventually I'll get a Canada Post email that a label has been created.


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## Susquatch (Nov 25, 2022)

Degen said:


> Sigh....sorry I have to write this....
> 
> OMG OMG no pin, pin broken, what am I to do????? Take it to a machinist to fix it.....W A I T!!! (Insert your won name here) I am a machinist, problem solved.
> 
> You guys so funny.



I must have missed something. I have no idea what is funny about us guys. I'm busy as an ant on a hot chocolate bar harvesting my corn right now!

I do agree with you though. The pin is not a big deal. I bought a small bag of 10 plain set screws and just turned two down to fit my mill spindle and the R8 collet slot. It was easy peasy to do and now I have a spare that I keep with my mill tools. I have not broken the new one since I put it in and I don't expect that I ever will. 

Anyways, it looks like @Eyecon has decided to get an MT3 spindle so the lock screw doesn't matter anyway!

@Eyecon - after you get your MT3, make sure you don't leave a holder in the spindle for more than a week or so. I've had mine get stuck in my old mill/drill on me more than once that way. I think it's best to remove it after use. I've never had that problem with my R8 mill. 

It's been a good discussion. Thanks for posting your question.


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## Susquatch (Nov 25, 2022)

Eyecon said:


> Feel free to PM if you need detailed help.



Personally, I'd much prefer that this type of discussion stayed on the main forum board rather than get lost in a PM. Its not personal or private. It's educational and informative. I think we all benefit from that. Those who don't care can just scroll down!


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## jcdammeyer (Nov 25, 2022)

Eyecon said:


> Do you have a dial or digital tool setter? The process would be to set the probe against the reference ground surfaces of the setter and then move the quill to and down on to the “plunger” of the setter until it reads zero. The tool setter is obviously zeroed relative to the reference ground surfaces(using a gage or 123 block) The difference between the machine absolute position when the probe triggered vs when the quill reached zero on the setter is the exact height of your probe trigger point relative to the quill(which is your WCS reference for tool heights and probe height in Z)


This is exactly what I ordered.  https://www.aliexpress.com/item/1005003797600365.html 
Looks like it can move 5mm from the 95mm height.  At least if 'itinerary' is distance it can move.  There's also an N/C overtravel switch which will be wired into the Z axis limit switch circuit.

I can bring the spindle down to a 1-2-3 block until it has friction clearance.    Set Z to zero at that point and then move it over and bring it down on the tool sensor until it trips.  A bit of math will tell me the height above the table that it will trip and it's supposed to be very repeatable so I can verify that too.


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## Tom Kitta (Nov 25, 2022)

To answer original question. R8 exists for a reason - if MT3 was good enough they would use that - BUT R8 was designed for a much larger machine - for BP to work with transfer of power of max 3hp (or maybe 5hp). However, the machine to use MT3 is much smaller than even smallest BP - the MT3 spindles AFAIK are cheaper to make than R8 and thus seller should give small discount. Other than that there is not really that much difference, how much can the MT3 taper stick or move under power in a small mill vs. R8? 
Note that if MT taper was "sticking" in the spindle it would not be used in a drill press where all force is down - certainly not in large drill presses with 5hp motors using MT5 - would not want that to stick 

Bottom line is R8 is more specialized for milling collet than MT3 BUT for a small mill it may not really matter. I wonder what say Dabbler has to say about this - did anyone do comparison tests that we know of? I mean someone had to.


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## Eyecon (Nov 25, 2022)

jcdammeyer said:


> This is exactly what I ordered.  https://www.aliexpress.com/item/1005003797600365.html
> Looks like it can move 5mm from the 95mm height.  At least if 'itinerary' is distance it can move.  There's also an N/C overtravel switch which will be wired into the Z axis limit switch circuit.
> 
> I can bring the spindle down to a 1-2-3 block until it has friction clearance.    Set Z to zero at that point and then move it over and bring it down on the tool sensor until it trips.  A bit of math will tell me the height above the table that it will trip and it's supposed to be very repeatable so I can verify that too.


Yes absolutely that’s a good way to go as well…should get you within 20-40um/.001-.002”. I think a slightly safer approach with this method is to bring the spindle down lower than the block then raise until the block barely slides under it. The tool setter I was referring to for more accurate/repeatable measurement is a manual one, like one of these: https://a.co/d/3dTcuDD
Useful for measuring your probe and also verifying that things are working before trusting the tool table…even though i have a couple of cnc routers which are not particularly super accurate, this type of setter really helped me validate my setup before ruining relatively expensive stock materials.


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## Eyecon (Nov 25, 2022)

Tom Kitta said:


> To answer original question. R8 exists for a reason - if MT3 was good enough they would use that - BUT R8 was designed for a much larger machine - for BP to work with transfer of power of max 3hp (or maybe 5hp). However, the machine to use MT3 is much smaller than even smallest BP - the MT3 spindles AFAIK are cheaper to make than R8 and thus seller should give small discount. Other than that there is not really that much difference, how much can the MT3 taper stick or move under power in a small mill vs. R8?
> Note that if MT taper was "sticking" in the spindle it would not be used in a drill press where all force is down - certainly not in large drill presses with 5hp motors using MT5 - would not want that to stick
> 
> Bottom line is R8 is more specialized for milling collet than MT3 BUT for a small mill it may not really matter. I wonder what say Dabbler has to say about this - did anyone do comparison tests that we know of? I mean someone had to.


Excellent points, and indeed the MT3 model is about 350 cad cheaper and is in stock vs the R8 which maybe hopefully will be in Canada in Feb. For the 350 I can get a decent starter TTS kit from Tormach including shipping or lots of cheaper Asian replicas to play around with. From what I read on UK and other European based forums, R8 is very rare there and folks over there seem to do just fine without it. I believe the popular Optimum bench top mill which is a bit bigger and heavier than the PM25 clone I’m getting uses MT4. Certainly in the world of VMCs you don’t see any of these older style machine tapers which is why I was lost and confused in making the decision. In any case, I don’t think MT3 is as rare here in Canada or the US especially with Asian imports.


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## jcdammeyer (Nov 25, 2022)

Eyecon said:


> Yes absolutely that’s a good way to go as well…should get you within 20-40um/.001-.002”. I think a slightly safer approach with this method is to bring the spindle down lower than the block then raise until the block barely slides under it. The tool setter I was referring to for more accurate/repeatable measurement is a manual one, like one of these: https://a.co/d/3dTcuDD
> Useful for measuring your probe and also verifying that things are working before trusting the tool table…even though i have a couple of cnc routers which are not particularly super accurate, this type of setter really helped me validate my setup before ruining relatively expensive stock materials.


I wanted a tool sensor to be able to connect into LinuxCNC because I'm using both TTS and R8 tooling.  Hence my trials and tribulations with my power draw bar.  So I want the ability to place a tool into some kind of R8 holder and move over and determine the length of the tool without some sort of external measuring rig like sold by Tormach.


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## Eyecon (Nov 25, 2022)

jcdammeyer said:


> I wanted a tool sensor to be able to connect into LinuxCNC because I'm using both TTS and R8 tooling.  Hence my trials and tribulations with my power draw bar.  So I want the ability to place a tool into some kind of R8 holder and move over and determine the length of the tool without some sort of external measuring rig like sold by Tormach.


Yes if you measure the tool each time with the tool probe you are getting, knowing the probe height is irrelevant, all you need to determine is the offset between your WCS zero and the top of the sensor. I have this setup as well on one of the routers I use mainly for wood and composites because dimensional accuracy is not as critical.


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## Eyecon (Nov 25, 2022)

Don’t get me wrong though, there are so many ways of doing this and from my experience they all get you to the same result.


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## Susquatch (Nov 25, 2022)

Tom Kitta said:


> Note that if MT taper was "sticking" in the spindle it would not be used in a drill press where all force is down - certainly not in large drill presses with 5hp motors using MT5 - would not want that to stick



I guess it depends on your definition of sticking. My mill drill is a big drill press. Then again, so is any mill. Lots of times used for vertical drilling. 

It sticks (by my definition) all the time. On occasion after a lot of heavy drilling I have to literally pound on the drawbar. To the point that I added a heavy duty anvil to the top of the drawbar. I use a heavy brass hammer on it. 

On the other hand, my R8 has never required more than a light tap with a plastic mallet. 

I think that is the reason that they call the R8 a semi-self-releasing taper. 

I should add that my mill/drill is an old girl. It has a 3/8 set screw built in to the spindle nose to help hold an installed taper provided that the taper has the corresponding flat for it.


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## David_R8 (Nov 25, 2022)

Since the topic of sticking MT3 tapers I went out to see if mine was stuck. It's been tightened to working tension with a TTS holder since August. Undid the drawbar a few turns and rapped the drawbar with the end of the ratchet and out it came.


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## Dabbler (Nov 25, 2022)

I've never been biased against MT3 - all my lathe tail stocks use it - but I have a slight preference for R8.  But it isn't worth a lot of wait and uncertainty.

BTW  I have had, in an exceptional circumstance, had an R8 stuck - I was stupid -  but it came out OK when I realized my mistake.

My preference for R8:  I have used 3/4 inch cutters in both.  I think the alignment and holding is actually slightly better in R8, but that is a completely subjective thought.  I seem to crank down on MT3 more on larger cutters.  but hey - they both work.


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## Susquatch (Nov 25, 2022)

David_R8 said:


> Undid the drawbar a few turns and rapped the drawbar with the end of the ratchet and out it came.



You rapped your drawbar with a steel ratchet? I've always been told that was a big no-no. Might also explain why yours doesn't stick. So would oil.


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## Six O Two (Nov 25, 2022)

I've had RF30 clones with MT3 and R8 tapers. My current mill has an r8 taper, even if my lathe has an MT3 tailstock. There wasn't a lot of tool overlap with the lathe when I had the milldrill with an MT3 taper as most of my lathe tools already had a tang instead of threads for a drawbar.

Like many others in this thread, I much prefer R8 for a mill. My tools used to get stuck in my mt3 milldrill all the time, and I often had to break out the drifts to get them out lest I fowl up the threads on the drawbar. That was a huge pain compared to R8 tooling.

R8 generally has easier/better re-sale as well in my experience.


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## David_R8 (Nov 25, 2022)

Susquatch said:


> You rapped your drawbar with a steel ratchet? I've always been told that was a big no-no. Might also explain why yours doesn't stick. So would oil.


Yup, I don't have a fancy hammer with a socket on it so I just rap it with the butt end of the ratchet handle.


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## jcdammeyer (Nov 26, 2022)

Some rambling...

One of the principal issues with MT tooling is it doesn't handle lateral (side) forces very well.  It's why you can have MT on the tail stock or spindle for centers and drill bits.  

But try and mill with a cutter held in the drill press chuck and be prepared to wear it.  Literally and perhaps internally.  That's why a drawbar for MT tooling is mandatory!

Taper angle is 1.4377 theoretically for a length of 3.19".  The small diameter is 0.7780" so let's just make it a cylinder rather than a cone to simplify the math.   Pi x D x L is 7.7968 square inches.  That's roughly the surface area in contact with the MT3 socket.  If it's wedged in tightly making contact that's a lot of friction area.  And because it's such a small angle a large distance is required before it's no longer touching or at least loose.

Now let's look at R8.  The angle now is 8 degrees 25.5 minutes.  Length of engagement is 0.94" and this angle is too steep to consider it a cylinder from 1.25" to 0.94".
Using this calculator:
https://keisan.casio.com/exec/system/1223372110
Surface area is 5.19 square inches.  Doesn't seem that different.

However the angle and length of engagement is dramatically different;  essential 1/3rd.  And since the angle is steeper the distance between the collet and the spindle increases more rapidly and so releases faster and therefore more easily.  

I believe because the angle is so shallow and over such a long length that unless the tapers are absolutely identical MT tapers don't contact completely until they are under a lot of force and then they sort of flex into contact making them harder to separate.  Lateral vibration will in effect wiggle it loose.

Based on the testimonials most often MT3 drops out once the drawbar is loosened with only a light tap to shake it free.  It's been many years since I pulled an MT3 holder into the drill press spindle.  I don't remember having trouble releasing it.

I know I have to use the wedge and a hammer to release the pressed in Drill Chuck MT3 holder.


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## Eyecon (Nov 27, 2022)

So a bit of bad news: it seems I was dealing with a bait and switch seller on eBay, after chasing them for the past couple of days to switch my order to the MT3 version they told me it’s not in stock and I have to wait until next February. I opened a dispute with eBay to get my money back. Looks like I’m going to end up getting an R8 mill after all 
(I don’t ever do this but for reference seller is sumaiglobal42…things escalated really badly so leaving the name here because I wouldn’t want to see anyone go through this experience)

Now I’m looking for recommendations for something similar to the PM-25 work envelope (19x7) with a brushless motor and belt drive. Any suggestions? 
I’ll contact PM tomorrow to inquire about shipping but open to other suggestions.


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## YotaBota (Nov 27, 2022)

David_R8 said:


> Yup, I don't have a fancy hammer with a socket on it so I just rap it with the butt end of the ratchet handle.


The right tool for the job! LOL
BTW - chisels make great screwdrivers. LOL


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## jcdammeyer (Nov 27, 2022)

Eyecon said:


> So a bit of bad news: it seems I was dealing with a bait and switch seller on eBay, after chasing them for the past couple of days to switch my order to the MT3 version they told me it’s not in stock and I have to wait until next February. I opened a dispute with eBay to get my money back. Looks like I’m going to end up getting an R8 mill after all
> (I don’t ever do this but for reference seller is sumaiglobal42…things escalated really badly so leaving the name here because I wouldn’t want to see anyone go through this experience)
> 
> Now I’m looking for recommendations for something similar to the PM-25 work envelope (19x7) with a brushless motor and belt drive. Any suggestions?
> I’ll contact PM tomorrow to inquire about shipping but open to other suggestions.


It's really too bad that places like House of Tools and some of the other industrial ones vanished.  KMS Tools has far more space dedicated to battery operated hand tool brands and what used to be a fairly nice metal working section is shoved off in the corner.    So being able to buy local has changed dramatically over the last few years.  

Busy Bee is gone from Vancouver for who knows how long.  They used to keep a decent supply of metal working stuff too.   On the island we had Island Saw and Sharpening service.  They are gone.

Perhaps the market is saturated.  All the baby boomers have purchased what they wanted.  GenX was never that interested and the successive generations are inheriting or buying the stuff the boomers purchased.

And then there's the 3D printers.  I suspect that many who would have gone into the metal hobby requiring a lathe and a mill bought a 3D printer and that keeps them more than busy enough.  And indirectly I'm one of those.  Although I have the sheet metal tools I rarely make a metal box.  So much easier to print a plastic one.

All things being equal I'd still consider Grizzly Tools for new hardware.


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## David_R8 (Nov 27, 2022)

jcdammeyer said:


> It's really too bad that places like House of Tools and some of the other industrial ones vanished.  KMS Tools has far more space dedicated to battery operated hand tool brands and what used to be a fairly nice metal working section is shoved off in the corner.    So being able to buy local has changed dramatically over the last few years.
> 
> Busy Bee is gone from Vancouver for who knows how long.  They used to keep a decent supply of metal working stuff too.   On the island we had Island Saw and Sharpening service.  They are gone.
> 
> ...


I very nearly bought my wood lathe from Grizzly. Had the exchange rate been better I likely would have.


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## jcdammeyer (Nov 27, 2022)

Many years ago now I had a discussion with a friend about mill prices.  I bought mine new from House of Tools for I think $3300 before taxes.  It seemed like a lot of money but it turns out not.  Here's the simple math.

Driving really old truck.  Say I wanted a new F150 that starts at $45K.  Put 10% down and payments for 5 years at 9% interest run $830 per month.

Don't let your eyes glaze over just yet....

So that's $830 x 12 = $9960.    OK.  Old vehicle might require $1660 per year in service.  Seems high but remember payments for a new one cost the same for two months.  

If we reserve $1660 to maintain the beater vehicle, and pretend we'd be paying the rest for a new F150 we actually can afford a mill for $8300.  

Here's one on sale for $7699 which with taxes is $8622  (remember I didn't add taxes to the truck purchase).








						KNEE MILL VERTICAL CRAFTEX CX SERIES CX603
					

This heavy duty knee mill has the power and space to make quick and accurate work of just about any machining job you can throw at it.




					www.busybeetools.com
				




The gist of the discussion so many years ago now was that we have no trouble buying a new vehicle with payments or go on an extended holiday for $10K.  But the mill has a low price limit for some reason.  Yet it's actually quite easy to afford as long as you decide to forgo something else.   Depreciates way less than a car.  Can even earn it's price back.


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## Dabbler (Nov 28, 2022)

This unit is very similar to the first mill I bought and used for just under 20 years.  very good work can be one on this type of machine.


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## Susquatch (Nov 28, 2022)

David_R8 said:


> Yup, I don't have a fancy hammer with a socket on it so I just rap it with the butt end of the ratchet handle.



Each to his own I guess.... 

What do you use to seat parts in your mill vise? My vise is a self seating Gerardi Spa. I thought you had a Kurt?

........ 

You have been around machine tools for a million years. I'm not gunna pretend to try and break or change your habits. The following is just a suggestion for others reading this thread. 

They sell these really cool tools called ratchet wrenches. Basically, they are a combination wrench with a ratchet on the box end. That's what I use on my spindle. I bought a single 3/4 ratchet wrench that lives full time on my mill. It does double duty as a vise handle too. 

I suppose for those who feel the need to use the same tool to break the taper friction, one could cut the open end off and insert it into a dead blow hammer - or make a dead blow hammer end to fit it. 

I much prefer to use a plastic mallet. It always breaks my R8 taper with a very light tap and never damages the hex on my spindle. It also does double duty to break the taper connection on my lathe chucks and to seat parts in my vise for those few times that is needed. There is something about the way that plastic absorbs impacts that works better than brass or hard rubber to seat parts and loosen tapers.


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## Dabbler (Nov 28, 2022)

I just got one of those fancy hammer/wrench deals with a brass hammer part, used.  

For over 30 years I have used a double ended box wrench:  I had to order it from Sears/Craftsman in the US, as Canada stopped carrying them:  It has a 3/4 box end and a 7/8 box end.  The one end is for the drawbar, and the other is for the hold downs.  It is also the perfect weight to give the drawbar a sharp rap.


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## historicalarms (Nov 28, 2022)

jcdammeyer said:


> Many years ago now I had a discussion with a friend about mill prices.  I bought mine new from House of Tools for I think $3300 before taxes.  It seemed like a lot of money but it turns out not.  Here's the simple math.
> 
> Driving really old truck.  Say I wanted a new F150 that starts at $45K.  Put 10% down and payments for 5 years at 9% interest run $830 per month.
> 
> ...


 
still a belt driven machine A LOT of money to change belts every time you need a tool speed change, personally I would very much prefer any used gear driven machine with transmission at 1/2 the price regardless of tool mount provisions.


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## historicalarms (Nov 28, 2022)

Any box end or ratchet end wrench wouldn't work on my draw bar head...When I set a taper into the socket I dont just "snug" it up, I tighten it securely and that damn bar head gets peened something awful with the force of very firm hammer whacks it takes to release the taper. 
    In 20 yrs of using the same draw bar & MT tooling I can see no damage to either except that hex head.

     I have had the taper (drill chuck) turn a couple times in my lathe tailstock (no draw bar of course) but never has one come loose in the mill  LOL


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## jcdammeyer (Nov 28, 2022)

historicalarms said:


> still a belt driven machine A LOT of money to change belts every time you need a tool speed change, personally I would very much prefer any used gear driven machine with transmission at 1/2 the price regardless of tool mount provisions.


Or replace the single phase motor with an AC Servo and run 1 RPM up to 3000 RPM.


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## StevSmar (Nov 28, 2022)

Eyecon said:


> …and some ridiculous customs clearing fees…


PM charged me around 1% of my purchase cost for brokerage of my Mill. I considered that a bargain to allow the Mill to show up in my driveway with no effort on my behalf.
(except for financial effort of course…)


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## Darren (Nov 28, 2022)

Degen said:


> Sigh....sorry I have to write this....
> 
> OMG OMG no pin, pin broken, what am I to do????? Take it to a machinist to fix it.....W A I T!!! (Insert your won name here) I am a machinist, problem solved.
> 
> You guys so funny.



I don't have a pin in my R8 mill, and don't miss it.  If R8 was going to slip, 3/4" TTS would slip like crazy.


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## Eyecon (Nov 28, 2022)

So folks another decision to be made since the eBay deal fell through. PM-25MV or LMS 6700? I got quotes from the two companies including tax, freight, brokerage etc. Basically I can get the LMS 6700(SIEG SX3.5) for the same price as PM-25MV with a DRO, a table and a set of R8 collets. The only reason I'm more attracted to the 6700 is the 1000W motor and 5000RPM top speed. I plan to do a CNC conversion for the mill as mentioned before so while I don't really need the DRO, the linear scales will come in handy for CNC encoder feedback on all axis. 

 I'm paying a lot more than I initially planned anyway but I'm not sure which is the better machine in terms of quality and if the extra travel and motor on the 6700 is worth giving up all the other goodies that will come with the PM

Thoughts/recommendations/advise?


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## Degen (Nov 29, 2022)

Look no matter what manual mill you buy you will have to do internal upgrades at some point (ie  to ballscrews) because CNC will wear your leadscrews because of the increased usage, remember CNC can keep cranking when the human is exhausted.

Second you will need to stay on top of your ways and keep them snug and oiled.

I've converted my BB CT054 (now a CX603) to CNC.

I am less concerned about having linear scales as I don't use or recommend steppers.  Servos are the way to go (and they are quieter).  The best alternative is Teknic's Clearpath SDSK servo which has a encoder built in handles step and direction signals (ie stepper input) and size for size out performs steppers.

Also consider a BB CX611.

Best recommendation I can give is get a machine, get milling and have a blast.


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## Eyecon (Nov 29, 2022)

Degen said:


> Also consider a BB CX611


I looked at that but at 1800 rpm and 6” of y travel it doesn’t seem like a good option for 3400 cad. I also didn’t think the front mounted Z handle would make it a good candidate for CNC conversion.



Degen said:


> I am less concerned about having linear scales as I don't use or recommend steppers. Servos are the way to go (and they are quieter). The best alternative is Teknic's Clearpath SDSK servo which has a encoder built in handles step and direction signals (ie stepper input) and size for size out performs steppers


I’m not too sure about that. I get servos for sure in terms of speed and torque under certain conditions. But with the affordable lower grade ball screws that we all use for these conversions, and lost motion because of ways vs linear guides, I’d rather get feedback and correct the output based on the actual position of the table not the motor shaft.



Degen said:


> Best recommendation I can give is get a machine, get milling and have a blast.



Roger that!


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## jcdammeyer (Nov 29, 2022)

Darren said:


> I don't have a pin in my R8 mill, and don't miss it.  If R8 was going to slip, 3/4" TTS would slip like crazy.


My understanding of the pin is that it's there to prevent the Collet from turning while the turning draw bar pulls it up and starts to apply tension.  Once that's started the pin doesn't do anything anymore.   Which, as you've said, must be true if you don't have one and your collet hasn't spun.


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## Susquatch (Nov 29, 2022)

jcdammeyer said:


> My understanding of the pin is that it's there to prevent the Collet from turning while the turning draw bar pulls it up and starts to apply tension.  Once that's started the pin doesn't do anything anymore.   Which, as you've said, must be true if you don't have one and your collet hasn't spun.



Yup, that's what I said above too. 

I'd only add that my mill has extremely low turning resistance. I like the assistance that the pin gives me.


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## Darren (Nov 29, 2022)

If i used R8 collets in the spindle nose more, I think I'd probably want the pin. With the power drawbar and the tooling I use I haven't had an issue just holding onto it while tightening


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## Susquatch (Nov 29, 2022)

Darren said:


> If i used R8 collets in the spindle nose more, I think I'd probably want the pin. With the power drawbar and the tooling I use I haven't had an issue just holding onto it while tightening



You have just hit on the one reason I might want a power draw bar. Till your note just now, I have not considered it. 

My issue is holding tools in place while I tighten the draw bar. I only have two hands. And I'm not about to hold a sharp cutter in my mouth! One hand to hold the endmill tool, another to hold the spindle, another to hold the brake, and still another to crank the drawbar wrench... Yup, a power draw bar might come in handy!


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## jcdammeyer (Nov 29, 2022)

Susquatch said:


> Yup, that's what I said above too.
> 
> I'd only add that my mill has extremely low turning resistance. I like the assistance that the pin gives me.


As long as my system is enabled the AC servo locks the spindle so other than spinning the pulley in the belt it's not much of an issue.

Now, if you add a WUT underneath your draw bar nut then you can hand turn the drawbar until it captures the collet.  Keep turning until the drawbar snugs up.  Then grab two wrenchs, one for the WUT and one for the draw bar and heave at it.


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## jcdammeyer (Nov 29, 2022)

Just to add some photos here.  The WUT sits under the draw bar.  In this case the round part and the nut of the draw bar are all one piece even if it might not look like it.  The shoulder on the draw bar registers in the WUT.





Ideally the WUT would have a shoulder that registers inside the spindle but there isn't room for that.  I'd have to remove the spindle and bore a larger hole in the top.

Anyway, add a 24mm wrench to keep the WUT from turning as in this photo.




I set my large torque wrench to 25 ft-lbs and tightened until the wrench went click signalling 25 ft-lbs.  I was able to keep the spindle from turning by just hanging onto the 24mm open end wrench with my left hand.
It took a bit more than 25 ft-lbs to undo but again, once loose enough to turn by hand I can catch the TTS tool holder or keep going to drop out the R8 collet.

One doesn't really need a spindle lock.  I installed this WUT on my mill right after the Home Shop Machinist article came out maybe 10 years ago?  Amazing how well it works.

One day I'll pull the spindle out and create a registration hold for a WUT with a shoulder.


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## Susquatch (Nov 29, 2022)

jcdammeyer said:


> Now, if you add a WUT underneath your draw bar nut then you can hand turn the drawbar until it captures the collet. Keep turning until the drawbar snugs up. Then grab two wrenchs, one for the WUT and one for the draw bar and heave at it.



My mill drill uses a similar concept except the WUT (as you call it) is on top. But same difference. The WUT is used to stop the draw bar from turning, and the nut underneath it is used to draw the drawbar up and tighten the collet. 

The issue on my mill is different. My problem is that I don't have enough hands. The WUT system would add yet another hand requirement. That's going the other way and making the problem worse. The brake on the mill eliminates the problem the WUT addresses. 

But how do you hold an endmill in a loose collet at the same time as you hold the brake and tighten the drawbar? 

I usually do this by holding the endmill and spindle with one hand and tighten the drawbar with the other. It takes a tight grip so I've cut myself on a sharp endmill more than once doing this. I have a similar problem using ER collets. 

Sometimes I lock the spindle by engaging both the back gear and the dog clutch. But I'm always afraid I'll forget and strip some gears engaging the power.


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## PeterT (Nov 29, 2022)

ER collets I don't have a problem with. Put the mill in low gear so there is some spindle resistance, hold the bloodthirsty end of EM with protection, tighten collet nut with other hand. It doesn't take much hand tightening to prevent drop out. Now hold brake & tighten drawbar. This operation is harder to do with R8 collet. Actually I can reach both EM & drawbar simultaneously, just. But I were much shorter or mill was much taller, not enough anatomy to span the gap. Maybe there is an old school trick to R8 insertion without power assist, but personally I never saw the romance to R8.


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## jcdammeyer (Nov 29, 2022)

I must be doing something wrong.  
Of course I'm mostly using the TTS holders.   If the R8 collet is in place I insert the TTS holder and turn the nut by hand about 1/2 a turn.  Now the tool stays in place.  Then the two wrenches and tighten.  

To loosen I might throw a rag under in case it drops out but normally loosen to finger tight using wrenches and then hold onto tool and finger loosen draw bar.  Then just a light tap on the draw bar and the tool drops out.

Now for R8, if you are loading a 3/8" 4 flute end mill right into the collet then first insert collet and again with fingers spin drawbar until it's almost all the way up.  Now insert tool into R8 collet and tighten.

Taking out is easier because now I can use two hands to loosen with two wrenches until finger tight or looser.  Of course all my tools have a sliding fit into the collet. 

If the tool is smaller than the collet then I can see issues but I haven't run into that.


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## Degen (Nov 30, 2022)

Eyecon said:


> I looked at that but at 1800 rpm and 6” of y travel it doesn’t seem like a good option for 3400 cad. I also didn’t think the front mounted Z handle would make it a good candidate for CNC conversion.
> 
> 
> I’m not too sure about that. I get servos for sure in terms of speed and torque under certain conditions. But with the affordable lower grade ball screws that we all use for these conversions, and lost motion because of ways vs linear guides, I’d rather get feedback and correct the output based on the actual position of the table not the motor shaft.
> ...


Think again about servos, my encoding the current set up is 0.00012 approx, had I paid a touch more it would be 0.000016 approx.  The first exceeds the accuracy of the mill.

Depending on which option you choose the servo encodes at 800 rev or 6400 per rev.

Even if I switch to ball screws with an approx pitch of 1/4" per rev on my servos that still translates as 0.0003"

My biggest stall was concerns about stalling and loosing step.  I must say my machine exceeds expectations and am able to push the machine and keep accuracy right up to the limit of the machine.


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## Degen (Nov 30, 2022)

I use R8 collets (though very rarely now), R8 Weldon style holders for certain sizes and now use R8-ER holders,  I have several and for the most part leave them set with the highest used tooling.

Most of my tooling now is Carbide and razor sharp, I've never had a cutting issue installing or removing.


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## Susquatch (Nov 30, 2022)

PeterT said:


> ER collets I don't have a problem with. Put the mill in low gear so there is some spindle resistance, hold the bloodthirsty end of EM with protection, tighten collet nut with other hand. It doesn't take much hand tightening to prevent drop out. Now hold brake & tighten drawbar. This operation is harder to do with R8 collet. Actually I can reach both EM & drawbar simultaneously, just. But I were much shorter or mill was much taller, not enough anatomy to span the gap. Maybe there is an old school trick to R8 insertion without power assist, but personally I never saw the romance to R8.



Bloodthirsty EM eh! Too funny. But also so true!

I'm plenty big enough to reach both ends with zero problems.




jcdammeyer said:


> I must be doing something wrong.



I don't think so! In fact, the only thing I've ever seen you do wrong is hook the negative lead of a scope to the wrong place!

You just are not using a loose Bridgeport Clone.

Since I don't plan to ever do CNC, I have no need to spend money buying or time making TTS holders. I'd rather use ER or even native R8 collets. The system is certainly cool though.

Peter & John - I really didn't intend to make this into a bigger problem than it is.

My real problem is a very smooth free spinning Bridgeport type spindle and motor system with very low drag or resistance. What a horrible first world problem to have!

Normally I manage. The only time it gives me real heart burn is when the tool I am using is at the bottom end of the collet adjustment range so I have to hold it till I get enough grip on it with the collet. 

I shouldn't really complain.

Truth is that I should simply develop a habit of engaging the bull gear and the spindle clutch to lock the spindle and then remember to unlock it afterward to avoid crashing my mill. This and perhaps sell my collets and buy a set with a finer range so I can always easily tighten up the bottom end first as Peter describes.

FWIW, I just recently bought a set of metric collets that were on sale hoping it would partially accomplish this goal. Only time will tell how well this works! 

Thanks to both of you for so gratiously letting me vent a bit about my first world problem. And a huge thank you to @Eyecon for tolerating me hijacking his thread.


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## jcdammeyer (Nov 30, 2022)

Really only the people working with MT3 collets can answer how easily it is to swap out say a 1/2" two flute roughing end mill for a 1/4"" four flute finishing end mill.  How hard to bang on the draw bar to release it?  Does the cutter then drop out or stay in the collet while the draw bar is spun the 5 to 10 turns to remove it from the spindle.

I think in both cases, as long as the tap verses bang to release the collet from the spindle after a couple of turns of the draw bar either tooling is fine.  

For me, this conversation has reminded me that sometimes, when spindle to work distance is very short due to size of the product being machined, that a collet is a good solution compared to any kind of tool holder.  
I don't have any MT3 collets so I can't show that in the comparison but as the photo shows, being able to hold a tool in a collet as opposed to a holder of some sort can make or break the ability to mill something because of as much as a 2" gain in space from spindle to work.

Here they are lined up even with the bottom of the spindle.


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## David_R8 (Nov 30, 2022)

On my mill the MT3 collets hold the cutter well even when the drawbar is loosened. The exception is the TTS-style holders which because they are heavier can slip down when the drawbar is rapped.


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## PaulC (Nov 30, 2022)

Gentlemen
All the above discussion about 3MT vs R8 collets reminded me of something I found in a recently received "box of bits".

I have eleven 3MT collets of various sizes that I have no need of, and there are also a few CAT 40 taper tool holders (mostly shell end mill holders).  To this end if any member would like them, if you are within practical driving distance of Blind River, Ontario (midway between Sault St. Marie and Sudbury, Ontario on Highway 17), you are welcome to get in touch with me and they are yours for the taking, gratis.  If there are no "local takers" but someone further away would like them, all I would ask for is coverage of the shipping costs  (Exact shipping only, no mark ups!!!).   

Collets:  1 of 1/8,   2 of 3/16,   1 of 1/4,   1 of 5/16,   2 of 3/8,   1 of 7/16,   2 of 1/2,   1 of 11/16                    Draw bar thread:  3/8 X 16
They are used, but are not dinged up.  I can't find any name brand, just sizes marked on each collet.

If any member is interested, my email is:       excello.4827@gmail.com

Thanks

Paul


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## 140mower (Nov 30, 2022)

PaulC said:


> Gentlemen
> All the above discussion about 3MT vs R8 collets reminded me of something I found in a recently received "box of bits".
> 
> I have eleven 3MT collets of various sizes that I have no need of, and there are also a few CAT 40 taper tool holders (mostly shell end mill holders).  To this end if any member would like them, if you are within practical driving distance of Blind River, Ontario (midway between Sault St. Marie and Sudbury, Ontario on Highway 17), you are welcome to get in touch with me and they are yours for the taking, gratis.  If there are no "local takers" but someone further away would like them, all I would ask for is coverage of the shipping costs  (Exact shipping only, no mark ups!!!).
> ...


If nobody local steps up, I will gladly pay the shipping.


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## David_R8 (Nov 30, 2022)

PaulC said:


> Gentlemen
> All the above discussion about 3MT vs R8 collets reminded me of something I found in a recently received "box of bits".
> 
> I have eleven 3MT collets of various sizes that I have no need of, and there are also a few CAT 40 taper tool holders (mostly shell end mill holders).  To this end if any member would like them, if you are within practical driving distance of Blind River, Ontario (midway between Sault St. Marie and Sudbury, Ontario on Highway 17), you are welcome to get in touch with me and they are yours for the taking, gratis.  If there are no "local takers" but someone further away would like them, all I would ask for is coverage of the shipping costs  (Exact shipping only, no mark ups!!!).
> ...


Where are you located?
Edit: my bad... I missed the location...


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## 140mower (Nov 30, 2022)

David_R8 said:


> Where are you located?


Pretty sure he mentioned Blind River, Ontario.


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## David_R8 (Nov 30, 2022)

140mower said:


> Pretty sure he mentioned Blind River, Ontario.


Whoops! I missed that...


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## YotaBota (Nov 30, 2022)

David_R8 said:


> Whoops! I missed that...


You must have spent to much time at my place last week,


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