trlvn's terrific travelling RF30 tale

[Susquatch]

I'm wondering if those bolts were originally metric? My LC-30 has metric fasteners.

I suppose that is possible. But mine are 1/2-13 the same as Craig's. So between you and I we are batting 50/50.

It would be interesting to see the measurements of the bolts using the wire system just to see what they measure have you tried a tap in the hole to see how it fits?

I'll try that in mine tomorrow too. But I doubt my bolts are original, and I'll bet that the threaded holes in mine are.

In any event, mine are just as loose as Craig's are.

 

[Susquatch]

Just wondering, what is the difference between an LC-30A, an LC-30, and an RF30?

 

[YYCHM]

Just wondering, what is the difference between an LC-30A, an LC-30, and all RF30?

LC-30A, LC-30, @trlvn's Craftex B1976, and my House of Tools machine are all RF30 clones. Just larger round column mill/drills with manufactures/supplier improvements(?) to add to the confusion. King PMD-30 is another one.

These guys.. https://rongfu.com/mill-drill-machines/

LC-30A, LC-30 are Long Chang machines but still considered RF clones.

 

[trlvn]

I'm wondering if those bolts were originally metric? My LC-30 has metric fasteners.

It would be interesting to see the measurements of the bolts using the wire system just to see what they measure have you tried a tap in the hole to see how it fits?
Busy Bee’s base does have the little cabinet in it but I seldom use it other than storing the toolbox it came with.

For sure, some of the fasteners are metric. These particular threaded holes are 7/16-14 currently and I don't think there is any normal metric standard that is close. For example, I don't think they were previously M10 because if they were tap drilled for 7/16-14, it would not have cleaned out the prior threads.

Craig

 

[trlvn]

Mine has no washers at all. The Bolts on mine are all Grade 8 1/2-13 x 1.5" Socket Head Machine Screws. They look original. I have no idea at all why they were used in this application. Grade 8 Bolts into regular old cast iron doesn't make sense to me. Sorry about that..... Maybe a previous owner upgraded the bolts thinking stronger is always better???? Or maybe the clone boys wherever they are thought that too?

On close inspection, and assuming yours is similar enough to mine, I am still solidly on my original guess and MUCH LESS inclined to think yours failed by fatigue. I simply think yours was over torqued by a gorilla and the threads in the base were pulled out. Normally, the bolt would strip first, but a grade 8 bolt (if that's what yours had too) would strip the casting long before the bolt.

Thanks for checking for me. Sorry if I gave you the wrong impression but I, too, believe that 'Bubba' (the mythical previous owner) stripped the threads the old fashioned way--by pulling for all he was worth! I think he also failed to consider that he'd inserted a 1/4 inch plate that reduced the bolt's engagement in the casting. That coupled with the loose fit of the bolt in the hole meant that the threads in the cast iron crumbled.

Re 1/2-13 v. 1/2-20, the problem is, as @John Conroy pointed out, that the tap drill for 1/2-13 (27/64 or 0.4219) won't completely remove the existing 7/16-14 threads (0.4375). The tap drill for 1/2-20 (29/64 or 0.4531) will. Lots of people use 1/4-20 in cast iron so I expect that 1/2-20 ought to form OK threads. And I have nearly 1 inch of casting available so lots of threads.

I just don't have any experience with helicoils (or similar). I did, however, see a reference tonight that there are longer inserts available (7/8" v. 1/2"?). The kits seem to be pretty darn expensive, $78 at BoltsPlus?

Thread Repair Kits & Inserts

www.boltsplus.ca

So I bought 1/2-20 bolts this afternoon but haven't drilled and tapped for them yet. (My feet still get tired and swollen at times after the chemo.) As an aside, Home Depot had no Grade 2 or Grade 5 bolts in 7/16--either UNC or UNF?

Finally re Loctite, the problem is that these are the bolts that will be used for tramming the head. I don't want to have to torch them to get them free if the machine needs an adjustment.

@Susquatch I do appreciate you sharing your experience. I may not be following your advice exactly but you are surely helping me understand the issues and think through the options. That is always good in my books!

Craig

 

[6.5 Fan]

I never checked to see what metric might be close to your size, you did mention that Bubba had been at the machine previously. The bolts on my mill are socket head cap screws like Susquatch has and are original.

 

[Susquatch]

Thanks for checking for me. Sorry if I gave you the wrong impression but I, too, believe that 'Bubba' (the mythical previous owner) stripped the threads the old fashioned way--by pulling for all he was worth! I think he also failed to consider that he'd inserted a 1/4 inch plate that reduced the bolt's engagement in the casting. That coupled with the loose fit of the bolt in the hole meant that the threads in the cast iron crumbled.

Re 1/2-13 v. 1/2-20, the problem is, as @John Conroy pointed out, that the tap drill for 1/2-13 (27/64 or 0.4219) won't completely remove the existing 7/16-14 threads (0.4375). The tap drill for 1/2-20 (29/64 or 0.4531) will. Lots of people use 1/4-20 in cast iron so I expect that 1/2-20 ought to form OK threads. And I have nearly 1 inch of casting available so lots of threads.

I just don't have any experience with helicoils (or similar). I did, however, see a reference tonight that there are longer inserts available (7/8" v. 1/2"?). The kits seem to be pretty darn expensive, $78 at BoltsPlus?

Thread Repair Kits & Inserts

www.boltsplus.ca

So I bought 1/2-20 bolts this afternoon but haven't drilled and tapped for them yet. (My feet still get tired and swollen at times after the chemo.) As an aside, Home Depot had no Grade 2 or Grade 5 bolts in 7/16--either UNC or UNF?

Finally re Loctite, the problem is that these are the bolts that will be used for tramming the head. I don't want to have to torch them to get them free if the machine needs an adjustment.

@Susquatch I do appreciate you sharing your experience. I may not be following your advice exactly but you are surely helping me understand the issues and think through the options. That is always good in my books!

Craig

I get no wrinkles in my shorts when people don't do what I suggest. My whole career world has always been full of teams who share their knowledge and ideas and then the best is picked by team consensus or team leader - you are the team leader on this project

I don't know why I thought your bolts were 1/2-13 too. Maybe it's because you were talking about replacing your Bolts with 1/2" ones. If I had known yours were 7/16-14, I would have recommended 7/16-14 Helicoils. The nice thing about helicoils is that you use the original size bolt. The original hole is merely tapped to have deeper threads with a special tap that comes with the helicoil kit. Then the helicoil is turned into the new threads and the old size bolt is re-installed. Because helicoils are a high grade steel, and because the hole in the old material is a tiny bit bigger, the new female half of the connection is almost always stronger than the original. That would certainly be the case in cast iron. Just to give you some comfort, they are often used to repair cast iron cylinder heads when Bubba strips the spark plug hole - which is a much more severe and critical application than yours. I have also seen them used in an original design to improve the female side of a weak connection right from the factory - eg a short hole.

The kit for 7/16-14 is only $37 at Canadian Tire and includes the tap and 3 coils. You can probably get it even cheaper elsewhere.

https://www.canadiantire.ca/en/pdp/oemtools-thread-repair-kit-unc-7-16-in-14-0251216p.html

I certainly didn't mean to suggest using red loctite, just blue which needs no torch. But it should be fine without the loctite. Just mark the bolt head and flange so you know it isn't moving. I was only suggesting it so you could go with a lower torque value and not worry about the cast iron threads pulling out again or about the bolt coming loose.

Even if you don't try the helicoils in your mill, you should try helicoils sometime. They really are a miracle solution to a nasty problem and are very very easy to use. They belong in your "solutions handbook". I use them on farm machinery fixes all the time.

I was fully intending to follow @John Conroy's advice and use them to hold the Turret on in my Bridgeport (a much bigger load than your application but still basically exactly the same situation) until I discovered that the whole ear on the retaining spider had broken off. I even bought the 1/2" helicoil kit. The new spider arrives here on Monday.

Enough is enough. At this point, I feel confident that you know as much as you need to know to make a good decision.

But all-in-all, I am still glad to have had the discussion with you because I did not know that shimming the column was required to tram the head. Mine has never been touched. I have only ever trammed the X axis, not the y.

It just so happens that I am working on a new 3 gauge x-y tramming fixture right now. I already have the gauges and the gauge plate and I have ordered the material to make the wobble plate from. I will use the new fixture on my old mill/drill to check and adjust my Y tram. It might make it easier to do.

What kind of shims do you use, and how much of a PIA is that process, and how do you decide when enough is enough?

 

[trlvn]

What kind of shims do you use, and how much of a PIA is that process, and how do you decide when enough is enough?

So far, I haven't trammed the head. Just given the design of my machine, there is no other place to shim if it is needed. When I get the table back on, I'll be checking it for the first time. Previously, it seemed a waste of time to tram the head since I intended to disassemble everything for the move to the basement.

Craig

 

[Susquatch]

So far, I haven't trammed the head. Just given the design of my machine, there is no other place to shim if it is needed. When I get the table back on, I'll be checking it for the first time. Previously, it seemed a waste of time to tram the head since I intended to disassemble everything for the move to the basement.

Craig

I understand. Heck, I've had mine for 8 years in a big shop and I never did it because I didn't even know it could or should be done!

I'll be looking forward to hearing how you made out when & if you do it.

 

[historicalarms]

I think maybe my picture is making it look worse than it is. The legs splay a bit and the feet cover about 22.5 inches left to right. The spindle is about 10 inches from the column, centre to centre. So the spindle centre is just inside the feet. I have never rotated the head straight back. In that case, the spindle would be beyond the feet. Whether the mass of the stand and base would be enough to keep it upright, I don't know. I'll certainly be careful if I ever find a need to do that.

Craig

Certainly hate to be a "pup with a root that wont let go" but your measurements are still a concern for me...1/2 of 22.5 is 11 1/4 and you say your spindle is 10 ". If everything remains centered, of course your all right....but ....now traverse your table fully to one side or the other especially with a work-piece of any weight and that 1 1/4 inch counter balance is over-rode & gone and that thing will end up on top of whatever is underneath it in a hurry. Even if your head is pivoted 20 deg or so one way or the other (I frequently use this feature when operating mine, you can increase table usage by a few inches length this way ) can lessen stability with table fully traveled.

Again, sorry for the harping ...but I've seen many heavy things fall, most intentionally but not always and it falls faster than we can move.

 

[historicalarms]

I think maybe my picture is making it look worse than it is. The legs splay a bit and the feet cover about 22.5 inches left to right. The spindle is about 10 inches from the column, centre to centre. So the spindle centre is just inside the feet. I have never rotated the head straight back. In that case, the spindle would be beyond the feet. Whether the mass of the stand and base would be enough to keep it upright, I don't know. I'll certainly be careful if I ever find a need to do that.

Craig

Certainly hate to be a "pup with a root that wont let go" but your measurements are still a concern for me...1/2 of 22.5 is 11 1/4 and you say your spindle is 10 ". If everything remains centered, of course your all right....but ....now traverse your table fully to one side or the other especially with a work-piece of any weight and that 1 1/4 inch counter balance is over-rode & gone and that thing will end up on top of whatever is underneath it in a hurry. Even if your head is pivoted 20 deg or so one way or the other (I frequently use this feature when operating mine, you can increase table usage by a few inches length this way ) can lessen stability with table fully traveled.

Again, sorry for the harping ...but I've seen many heavy things fall, most intentionally but not always and it falls faster than we can move.

 

[trlvn]

Certainly hate to be a "pup with a root that wont let go" but your measurements are still a concern for me...1/2 of 22.5 is 11 1/4 and you say your spindle is 10 ". If everything remains centered, of course your all right....but ....now traverse your table fully to one side or the other especially with a work-piece of any weight and that 1 1/4 inch counter balance is over-rode & gone and that thing will end up on top of whatever is underneath it in a hurry. Even if your head is pivoted 20 deg or so one way or the other (I frequently use this feature when operating mine, you can increase table usage by a few inches length this way ) can lessen stability with table fully traveled.

Again, sorry for the harping ...but I've seen many heavy things fall, most intentionally but not always and it falls faster than we can move.

No problem, I understand the concern. The power feed unit on the left side adds and unbalanced weight. If I were to mount the bigger vise (6 inch) towards that side, together with a heavy workpiece, and raise and rotate the head, I could certainly see getting to the tipping point. However, I'm pretty conscious of the fact that it is a top heavy machine. Plus, almost all my work will be very small parts like models and so forth.

I recognize that it only takes one mistake...but I've been a woodworked for over 25 years and I still have all my fingers. There was that one incident, however, where about an inch of the end of the push stick disappeared in a blink of an eye. A close call can drive home a lesson like nothing else.

Craig

 

[YYCHM]

@David_R8 's stand is about the same speed. He indicated to me the bottom of the legs are 27" W X 24" D. @thriller007 what does that stand measure that you got with my machine?

 

[trlvn]

King Canada's PDM-30 mill/drill is in the same class, so I checked the stand they offer for it (SS-45):

STAND FOR MILLING/DRILLING MACHINE KING Canada - Power Tools, Woodworking and Metalworking Machines by King Canada

Optional stand for milling and drilling machines

www.kingcanada.com

L X W X H -- 31 X 21-1/2 X 28-1/4

That makes it a skitch more narrow than mine. I do note that it has the provision to be bolted down to the floor. Nonetheless, I think mine (31-3/4 X 22-1/4 X 30-1/4) is in a reasonable ball park.

BTW, I'm not sure the Busybee stand is really comparable since they don't sell an RF-30 type machine any more. I think their stand is intended for the smaller RF-45 class mini mill.

Craig

 

[trlvn]

Sigh.

So, rethreading the first hole--the damaged one--from 7/16-14 to 1/2-20 did not turn out as well as I might have hoped. The 29/64" tap drill kept grabbing as soon as it touched the existing (coarse) threads. It would then spin in the chuck no mater how much I tightened it. Going down to a 7/16 bit worked, however and then I was able to enlarge the hole out to 29/64. But there were still remnants of the old threads which I did not expect. Viz:



Perhaps foolishly, I continued on to tap 1/2-20 using what I think was a brand-new tap:



Pretty ugly threads.

If you peer into the hole, it seems to me that threads get more regular towards the bottom. Regardless, my new bolt does thread in decently and I'm pretty sure that there are enough good threads for the application.

However, based on this result, I'm inclined to leave the other 3 threaded holes as they are. I'm going to grab some new 7/16-14 bolts and see if they fit the existing holes better. Always one more trip to the store.

Craig

 

[YYCHM]

Where you hand tapping? CI usually taps very nicely.

 

[trlvn]

Where you hand tapping? CI usually taps very nicely.

Yes. Tap engaged very easily and cut the threads with little effort. The cast iron 'chips' all fell through so it wasn't even necessary to do the twist-and-back-off dance.

Craig

 

[Susquatch]

Yes. Tap engaged very easily and cut the threads with little effort. The cast iron 'chips' all fell through so it wasn't even necessary to do the twist-and-back-off dance.

Craig

Funny, I would have thought I would know this, but I didn't. You just taught me something! All these years I've been doing the reverse dance in cast iron too, but because cast iron breaks those little chips off all on its own, I didn't need to. I just never thought about it. Thanks for the lesson!

I have a cast iron backplate that I plan to drill and tap very shortly. I'll remember this exchange!

 

[trlvn]

At the risk of boring everyone to tears, just one more post about these stupid threaded holes. Over the weekend, I started to reassemble the head. And stripped another threaded hole. Grrr. I swear I had a small ratchet and I barely snugged the bolt. But there was a little 'cruk' sound and suddenly the bolt turned very easily.

On the other stripped hole, I had previously drilled it out to 29/64 and tapped 1/2-20 with crappy results that I think have sub-par holding power. Plus, when assembling the head, using the 1/2 inch bolt (instead of 7/16) it meant there was very little 'wiggle room'. I had to start the 3 7/16 bolts to get the head close to its final home and then I could get the 1/2 inch bolt to engage. So I really didn't want to upsize the other bolts to 1/2 inch or it would take a month of Sundays to get the thing together.

Plan "D" was to use a nut. On the side away from the operator, there is sufficient room inside the hollow casting for a washer and nut. That portion of the casting is actually very nice and smooth even though it has not been machined. So I drilled out the hole to 29/64. Again, that _should_ have removed all traces of the 7/16-14 threads but didn't. I did this for both holes on the side away from the operator. After that, it was relatively easy to put the head back on and secure it nice and tight.

Inside the casting on the operator side, there is not enough room for a hex nut or bolt head. There *may* be enough room for a 7/16" socket head cap screw. Should I ever strip the remaining 7/16-14 hole I think I'll change both of the fasteners on that side to SHCS coming up from the bottom.

Note I now have one 1/2-20 bolt, one 7/16-14 bolt and two 7/16 nut-and-bolt connections. What a dog's breakfast.

Craig

 

[trlvn]

Quick shot of the head going back on. Not how close I am to the overhead ducting. It remains to be seen if I'll be able to put the hinged portion of the belt cover back on top of the head.



Craig
(Yes, that is an old diaper pail photo-bombing this pic! It is clean and has been repurposed.)