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Mini Mill DRSs

#1
Title should have read Mini Mill DROs....

So, after much poking around I have concluded that I can add basic independent 3 axis DROs to my mill for around $150 or go for integrated 3 axis systems for $250-$400. Question is.... is the extra $$ worth it? How many of those extra functions are useful on a manual mini mill?

Mini Mill users chime in please.

Any and all input appreciated.

Thanks.
 
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Johnwa

Active Member
#2
if I understand what you mean by independent vs integrated then the one advantage of an integrated DRO is that it is easy to do bolt circles.
 

Bofobo

Well-Known Member
#3
Bolt circles is one small reason i went with integrated, now it also can numerically profile radius and store tool lengths as well apparently. Also the brighter larger display has always felt like a bonus. I did have to make some relief cuts on the column mounting plate for the scale on the back of the bed though. Because not enough room on the front for fush mounting because of the gibb screws
 

PeterT

Ultra Member
Premium Member
#4
Functionally they might do the same thing although admittedly I don't know much about independent. Maybe you can include a pic or link. You need to be able to see the display clearly so hopefully there is a wire from the encoder to the readout (as opposed to readout right by the scale kind of like a digital vernier). I personally don't use DRO bolt circle function much myself but that's only because I can spit those dimensions out in my drawing & usually its something oddball anyway. One thing I do a LOT is input an offset, so touch off an edge with a 0.200" diameter edgefinder, then input + or - 0.100" depending on if its on the left, right, top or bottom reference surface datum. This now 'zero's' the reference edge that you will be machining other features relative to. Similarly for less precise application you can kiss the edge with an end mill mounted, enter 0.000" then infeed the amount of material to be removed. Also as you are proceeding on a cut you will be measuring & comparing to the DRO so you need to be able to input an arbitrary number. Example DRO says 2.500 but you physically measure 2.502, you need to be able to input adjust to 2.502 & then carry on.

Most of the Chinese DRO boxes I see have tons of standard features. No issues that way. Its nice to be able to reverse the scale readout to set it up to your liking. There probably is an official machining standard or norm but for better or worse I chose X positive moving to the right Y positive moving away from operator. In quill feed/depth I have negative as depth. Another nice to have is adjusting display resolution so if you have crazy 6 digits after the decimal you can make it X.XXX on one axis or X.XXXX on another to suit your preference.

Another consideration is if you want to transport this DRO to another machine one day. If you need minimal features & will upgrade the machine to another that's one price point. If you spend some more & then sell the mill without DRO to use on another machine, thats another way to go. (Although the scales may not be usable based on length). Some things to noodle upon in that regard. Mostly I'd look for something that has been around & you can get replacement parts or at least compatibles.
 

Johnwa

Active Member
#6
I’ve only used the bolt circle and the divide by 2. With divide by 2 you can touch off each side and then move to the Center.
Anything else will require interpreting the chinglish manual and trial and error.
 

JohnW

Active Member
#8
I've used one of the BB LCD DRO's. It worked OK, but I found that is it very slow to update its position. That makes it quite annoying to use, but it did work OK to 0.001"-ish accuracy.
 
#9
I tried one of those BB LCD units on my mill and was very disappointed in it. Tried it a few times and got so many erroneous readings that I don't even attempt to use it again. It had no tolerance for even minimal machine vibration, the readings would jump all over the place if the machine was cutting.
 

kevin.decelles

Well-Known Member
Premium Member
#10
I just went with integrated (aliexpress). Just got it installed and calibrated. Mc’lovin it!

I too wanted it for bolt hole circles, divide by two etc and have found myself using the 200 datum point storage, abs/inc rules etc. Very useful

The unit I picked (pretty much at random) was delivered fast, well packaged and straight forward to install. Calibrating was tricky but I could probably do it again in a tenth of the time

If you are looking at standalone (B.B.) I believe @Dabbler may have one for sale

You could pop out for a tour and I could show you my install as well




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#11
I tried one of those BB LCD units on my mill and was very disappointed in it. Tried it a few times and got so many erroneous readings that I don't even attempt to use it again. It had no tolerance for even minimal machine vibration, the readings would jump all over the place if the machine was cutting.
Hey Doug,

Was that the IGaging DROs that BB sells?

Craig
 

Tom Kitta

Active Member
#12
I got IGaging DRO scales from BB long time ago - few years ago - never even installed them - you just reminded me I still have them all in a box. Have to post them on classified section for sale.
 
#13
I have been waffling between the two options for my mill for some time as well. I have watched several youtuber's do the install of the Iguaging units and adding a "touch DRO" to get the multi functions of the 3-axis unit. I don't know how this compares price wise after the whole song and dance is done. The price point of the I guaging units certainly appeals to me
 
#14
I have been waffling between the two options for my mill for some time as well. I have watched several youtuber's do the install of the Iguaging units and adding a "touch DRO" to get the multi functions of the 3-axis unit. I don't know how this compares price wise after the whole song and dance is done. The price point of the I guaging units certainly appeals to me
Price wise they appealed to me as well. $130 more gets you full function, but I wasn't sure I would ever use those functions. historicalalarms comment about his experience with the IGaging? units not handling vibration has me wondering.

In any event I ordered this

https://www.aliexpress.com/store/pr...ml?spm=2114.12010612.8148356.3.4fe03033M0MKMO

Around $318 landed. Less than a weeks delivery time. Ordered on Sunday and I missed the DHL delivery on Friday. Should see it tomorrow. So far I'm really impressed with aliexpress… so far.

Will let you know how things goes.
 
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kevin.decelles

Well-Known Member
Premium Member
#17
Calibrate? What's involved with that?
Depends on your install. I naively assumed the scales are perfect measuring tools...... not quite. After I installed the scales, as parallel and level as I could manage, I tried to validate if the scale was right. I used some 1-2-3 blocks , standards etc and found that my scales were off slightly. No matter how often I tried, always off -- but repeatable off

In the setup you can add linear compensation to account for fractions of a mm per m. Once I discovered this I can now measure very accurately and repeatably

As I said in another post, my next dro install will be much faster



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Tom Kitta

Active Member
#18
Yeah I guess I should check mine with a gage block. I can easily check for reputability - for distance is a bit harder.

I would not check vs. 1-2-3 block unless its a premium quality and quite new.

I am guessing my scales are within +-0.001 in say 10 inches but I can play around with it to get it more - the actual display is 0.0001 but just tightening the gibs has the effect of moving things around by 0.001.

If I ever get around to it I post the results.
 

kevin.decelles

Well-Known Member
Premium Member
#19
I don't have anything precision enough to test against so 1-2-3 was my standard using an edge finder etc.

I also verified to my dials over 10 inches and am within 0.0005 for what that's worth

Considering that without dro my dials were gospel, then the New Testament is as good as the old




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PeterT

Ultra Member
Premium Member
#20
I would not check vs. 1-2-3 block unless its a premium quality and quite new.
I am guessing my scales are within +-0.001 in say 10 inches but I can play around with it to get it more - the actual display is 0.0001 but just tightening the gibs has the effect of moving things around by 0.001.
I think we chatted about this on Kevin's post but I cant locate it right now. The longer the standard is, theoretically the more accurate you can calibrate the DRO. It doesn't have to be 123 or 246, those are just common blocks people may have. Because 0.001" grind tolerance over 3" block is a bigger discrepancy number than 0.001" over 6"block. But if you happened to have a longer rod of any arbitrary length like 14.923" that's perfectly fine because you are just indicating off that, comparing to DRO reading whatever it is & then entering the compensation factor to fudge them together. The trick is, how did you know the rod was exactly 14.923" to begin with? It all comes down to trusting the most accurate ruler.

I think this what people are counting on with 123 block stackups. If the the manufacturing tolerance is +/- 0.001" and you got a 50% random distribution with 2 smalls with 2 bigs, you have exactly 12.000". But unless you measured them with something better to validate, they could also be 11.996" - 12.004".

I doubt any of us are physically cutting to these tolerances in the real world of our mills anyways. But we can dream until a surface grinder shows up under the Christmas tree LOL

Yes a DRO does not lie when you lock down tables & see drift. Or our typically non-counterbalanced handles freewheel rotate a smidge & move the leadscrew a thou one way or another. Thats the beauty of DROs. They are just the messenger, they just read displacement independently.