Author Topic: Royal 5C lever collet closer failure and repair, hopefully  (Read 808 times)

Offline mikehinz

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Royal 5C lever collet closer failure and repair, hopefully
« on: February 15, 2019, 12:04:56 AM »
I've moved this topic to this part of the forum to avoid non-relevant posts getting into my post regarding the build of a PMR #1 Drilling engine.

I had a bit of tragedy on my lathe that will require some repair.  See the following 2 pix.

1st pix.



2nd pix.



Any guesses as to what that is?

To avoid suspense, I have a Royal 5C collet closer on my lathe, which is an Enco 13 x 40.  I'm the 2nd owner so I don't know how this was installed, but I assume by a distributor when the lathe was sold.  That's the spindle adapter that mates the spindle to the closer assembly.  The collet tube slides thru that piece and there's a notched disk that bolts up to the back of it that engages the closer handle assembly.  Whoever made this adapter did it incorrectly IMO.  The thread is 1.650 x 16 tpi and the ID is 1.50.  That's waayyy too thin and in time, it fractured at the thinnest point.  The metal is like tinfoil at the thinnest point and there's simply no need for that.  I've ordered a piece of 2 1/4" OD 1215 from HobbyMetalKits and plan to make the ID 1.40" which will clear the collet tube and still allow fairly large OD rod thru the spindle, although i almost never do such a thing.   I'll also try my hand at threading a large OD like which I hope will work as there's no other source for these now days, except making your own.

I'm in withdrawal over this as I use the 5C collet setup a LOT.

FYI and for everyone to join in my sorrow! :'(

Mike. 
MIke
Wichita, KS, USA

Online b.lindsey

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Re: Royal 5C lever collet closer failure and repair, hopefully
« Reply #1 on: February 15, 2019, 01:12:05 AM »
Condolences Mike. That really is a thin wall there where it broke. Hope you can sort it out and get it back like you want it and stronger!!

Bill

Offline steamer

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Re: Royal 5C lever collet closer failure and repair, hopefully
« Reply #2 on: February 15, 2019, 01:27:12 AM »
I hope what ever was in the chuck was A   light and B   not expensive!   Youll get it fixed....
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Offline mikehinz

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Re: Royal 5C lever collet closer failure and repair, hopefully
« Reply #3 on: February 19, 2019, 02:53:08 PM »
I hope what ever was in the chuck was A   light and B   not expensive!   Youll get it fixed....

I was extremely  lucky on this failure.  It came apart as I was installing the closer into the spindle.  So the lathe wasn't running and nothing was chucked up, hence no damage to anything else. 

Mike
MIke
Wichita, KS, USA

Offline mikehinz

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Re: Royal 5C lever collet closer failure and repair, hopefully
« Reply #4 on: February 19, 2019, 03:18:29 PM »
I don't know how much interest there will be in this but I've made substantial progress in getting this closer assembly repaired.  Someone might find something useful tidbit for other projects or problems.  I'll show what I've done so far in this post. 

The first thing I did was to call Royal Products and also Rovi as currently Rovi still makes lever style manually operated 5C closers mostly based on the Royal design.  Royal has long ceased production of this type of closer.  Both companies were helpful but essentially they'd machine an adapter from stock for me with no guarantee that it would fit after they finished it and of course the price would be extremely high for a one-off piece.   Royal did sent me a drawing for the adapter blank that was useful in that gave me the original ID and the bolt pattern. 

I thought carefully about how to design the replacement adapter to avoid future failures.  The big issue with the existing piece that failed was that its only .020" thick per side at the thread relief and of course in time, it simply fractured due to stress.  I spent some time with Fusion 360 designing a part that would hopefully last much longer, with the main goal to add some thickness to the thread relief area.  I've attached a PDF of the design that I came up with that gives me .085" per side or about 4.5 times thicker than the original piece.  Royal also recommended that it be made from 1215 so I ordered a piece of 2.25" OD round stock from HobbyMetalKits. 

BTW, I highly recommend HobbyMetalKits for short pieces as Bernie will ship for a flat $10 for stock 1' in length or shorter and he has lots of materials not listed on his website that he'll send if you ask via email.  The package just needs to be under 70# in order to get the best shipping rate. 

So the other challenge that I had coming how with a method of how I would be sure it would fit after completion.  There's no way to check the fit as the part needs to go into the other end of the spindle on the lathe I'm using to make the piece.  Plus 1.65 x 16 tpi is NOT a standard thread size.  The Good Book has data for 1 5/8" x 16 and 1 11/16" x 16 so I had that as a reference.  I did calculate the theoretic sizes via allowance and did manage to find a very useful thread calculator at the Theoretical Machinist website:

http://theoreticalmachinist.com/Threads_UnifiedImperial.aspx

Using my method and the online thread calculator I compared the results that I obtained with those from The Good Book for the 1 5/8 - 16 and 1 11/16 - 16 threads.  They matched exactly.  So I was pretty confident that I had the parameters for the threading correct for the required 1.65 x 16 thread. 

What i decided to do was to make some test pieces, first with AL and then with some scrap tubing I had in order to check the fit.  I had concerns if I would be able to thread successfully using the parameters that I had plus there was a potential issue on the eventual thread length and the distance to the shoulder since the replacement piece wouldn't necessarily thread all the way to the exact end of the thread on the ID of the spindle. 

This is post is getting rather long so I'll end this here and finish the work to date in another post.

Enjoy.

Mike
MIke
Wichita, KS, USA

Offline mikehinz

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Re: Royal 5C lever collet closer failure and repair, hopefully
« Reply #5 on: February 19, 2019, 04:20:51 PM »
This is a continuation post on the spindle adapter repair. 

One thing i didn't mention in the previous post was how I was able to change the ID to 1.40" in order to increase that very thin cross-section.  The answer is that there was already a 1.40" ID that restricted the ID.  I have no idea as to why they took out a section of it to 1.50" thereby weakening the adapter tremendously.   I doubt that I'll ever chuck up any long barstock between 1.40" and 1.50" that would go thru the headstock but if I needed to, I'd just remove this adapter. 

So, on to making the test pieces.  I just wanted to concentrate on the thread and making sure the lengths were correct on the threaded end.  First I used some 1.75" AL rod that I had on hand.  I turned the initial OD to 1.642" and commenced threading.  That's a so called 'laydown' threading tool and insert.  The insert designation is 16ER AG60 which is interpreted as Size 16 (3/8) External Right Hand, 48-8 tpi, 60 degree profile.  Note that this is partial profile type insert which means it can cut a wide variety of pitches but this type doesn't have a wiper wedge to completely form the thread vertex.  So you have to get the intended nominal OD correct before turning and then you'll have to properly file the thread crests after finishing the threading op.  The full profile type inserts are easier and faster to use BUT you have to have a different insert for each thread pitch you intend to cut.  For my hobby work the partial profile type works fine.  But if I was going to cut a lot of any specific thread, I'd for sure purchase the full profile type insert(s) for the job.


I ran the lathe at 260 rpm and of course had the leadscrew engaged with the gearbox set to 16 tpi.  Things happen pretty fast when threading but I had sufficient time to disengage the leadscrew before the tool ran into the shoulder.  I also ran my Unist micro drop lubricator during this as threading always generates a lot more load, heat, and friction than would at first be obvious.  Just a couple of more comments.  On the final post, I'll show some pix of the overall setup but I did set the compound to 29 degrees or so and advanced the tool with the compound.  I used the cross-slide with the DRO zero'd up with the tip of the tool just touching the work.  That way I retracted the tool after a pass using the cross-slide and always brought it back to the DRO X axis zero before the next pass and advanced the cut with the compound.  On the first 3 passes I advanced the compound .010 (radius measurement) and then advanced only .005 for the next pass or 2 and then finally .002 or .003 per pass toward the end.  Otherwise the load gets quite high.  Also on the very last pass I made a couple of passes without advancing the compound just to make sure the threads were clean.  I also lightly filed the thread top and touched them up with a bit of emery cloth and finally used some Scotch Brite to polish them up. 

I started measuring using thread wires and as usual, that drove me crazy.  I don't use them enough to be proficient.  The trick I'm showing here is to put a bit of heavy grease on each side of the part so you can get the mic over the wires.  The most important bit of advise is to clean up all the chips before trying to measure as you'll no doubt be searching for the wires whenever they get dropped!


On the first test piece, I got the pitch diameter (PD) to within the calculated range.  It wouldn't go for more than about 2 turns in the spindle meaning that I needed to cut the threads deeper.  I actually was able to rechuck the AL test piece and to get the threading tool back in position to pickup the existing thread to cut deeper.  As a result I was able to then thread the AL test piece fully into the spindle.  I also had to cut a bit off the nose in order to thread up to the shoulder.


Then on to attempting the same thing on some scrap tubing.  Shown is the 2nd test piece I made that actually properly threads in fully!  Here shown on top of the drawing.


Here the test piece being started into the spindle.


Here fully screwed into the spindle and shouldered up.


And the last pix of the test process.  The test piece laying on the print with a life-saving device that my brother loaned to me.  That's a Mitutoyo 1 to 2" thread mic with replaceable anvils.  And you can see that it even has a valid calibration sticker on it!   That mic is soooo easy to use and certainly saved me from heavily drinking which I would have resorted to if I had continued to use those thread wires.  My brother in a previous life ran the inspection department of a large W.. Texas based downhole tool manufacturing facility.  He has some nice measuring equipment!


On the PD, the calculated size was 1.6076 to 1.6015 for a 2A fit.  I had to go to 1.591 to actually fully thread the adapter into the spindle with a good fit.  So I ended up about .0105 under the min, but that's more than OK for this application. 

I'm supposed to get the stock I need today if there aren't weather related delays.  If it arrives I'm going to try to immediately make the actual adapter.  I don't want to let too much time go by on this as I'd probably forget exactly how I got to this point.

Hopefully the next post will be of the complete adapter!

Enjoy.

Mike


MIke
Wichita, KS, USA

Offline mikehinz

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Re: Royal 5C lever collet closer failure and repair, hopefully
« Reply #6 on: February 20, 2019, 01:23:07 AM »
Just a brief update on this project. 

The material I needed arrived late this afternoon.  I cut off about 3.5" inches of it and chucked it up in the 4J and indicated it in being careful to check it near the chuck and as far away from the chuck as possible.


Then I turned the end to be threaded to 1.642" as shown.  The material is 1215 and cuts very well.   I used an insert tool running about about 500 rpm with a pretty aggressive feed.  Even at the high feed rate, the finish was pretty good.  I also faced it to the exact length needed up to the shoulder.


And lastly turned the chamfer between the shoulder and the rear body of the adapter.  This material cuts well enough that I just advanced the tool into the work until I got the dimension called for.


I quit for today as it was getting late and I got tired.  I figured it's way better to start fresh in the morning on the most critical operation, that being the threading.

All for today.

Mike

MIke
Wichita, KS, USA

Offline 10KPete

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Re: Royal 5C lever collet closer failure and repair, hopefully
« Reply #7 on: February 20, 2019, 02:54:52 AM »
Mike, I like your approach and cool headed thinking. Making practice and test pieces is the right way to make sure you've figured correctly.

I'm watching and, as is usual with these things, learning a bit too.

Cheers!

Pete
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Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Offline Neil-Lickfold

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Re: Royal 5C lever collet closer failure and repair, hopefully
« Reply #8 on: February 20, 2019, 05:46:55 AM »
So did you make it a low engagement thread form? Ie did you make the minor diameter of the other part bigger, to allow for the shallower thread depth on the adaptor ? I have been seeing lately what are also called modified thread forms. So the thread pitch is still the same and so is the OD still the same and the effective thread diameter is still  the same, but the difference is just the minor diameter of the tread is way larger. In some cases it is about 1/2 the depth. When I have to make these, I take the standard full form insert, then just shorten the front of the insert to get the radial depth correct when the full form on the outside makes the correct diameter. So when thread cutting, leave the OD larger by 0.1 to 0.2 mm on diameter, and bring it down to the nominal size or the target size. The internal threads are just done with the standard internal insert, or the standard tap for that thread size is used, but the minor diameter is bored larger accordingly.
I am not sure how widely used the modified thread form is used, but for blowpin bodies or areas where a standard thread form does not leave enough remaining wall section, that is what we do.
Neil

Offline mikehinz

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Re: Royal 5C lever collet closer failure and repair, hopefully
« Reply #9 on: February 21, 2019, 09:34:29 PM »
So did you make it a low engagement thread form? Ie did you make the minor diameter of the other part bigger, to allow for the shallower thread depth on the adaptor ? I have been seeing lately what are also called modified thread forms. So the thread pitch is still the same and so is the OD still the same and the effective thread diameter is still  the same, but the difference is just the minor diameter of the tread is way larger. In some cases it is about 1/2 the depth. When I have to make these, I take the standard full form insert, then just shorten the front of the insert to get the radial depth correct when the full form on the outside makes the correct diameter. So when thread cutting, leave the OD larger by 0.1 to 0.2 mm on diameter, and bring it down to the nominal size or the target size. The internal threads are just done with the standard internal insert, or the standard tap for that thread size is used, but the minor diameter is bored larger accordingly.
I am not sure how widely used the modified thread form is used, but for blowpin bodies or areas where a standard thread form does not leave enough remaining wall section, that is what we do.
Neil

Neil, the problem I had/have with this is that the matching part is the lathe spindle which I did not want to dismantle as I have no other lathe to work with.  I'd have had to sent it all out then and it would get blindingly expensive.  I did finish the adapter, which I'll document here shortly, and my observation is that the assembly, that is both the spindle ID thread machine work and the adapter was done in a fairly sloppy manner and simply doesn't exactly conform to the UN specs.  So my approach was to simply make the adapter piece work in the existing spindle.  It turns out that the fit is really 1A vs 2A, at least that's what I think.  In any case I was able to make the adapter fit and fit quite well while at the same time, hopefully overcoming the weak section that lead to the break in the first place.

FYI.

Mike
MIke
Wichita, KS, USA

Offline mikehinz

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Re: Royal 5C lever collet closer failure and repair, hopefully
« Reply #10 on: February 21, 2019, 10:35:27 PM »
So, good news!  I managed to successfully make the adapter and fit it ot the lathe!  I'll document the process in this post.

Here's a wider view of the threading operation.  Shown is the compound set to 29 degrees, the laydown threading tool, the stock chucked up in the 4J, the Unist mql nozzle, and the threading operation almost complete.   As on the test pieces, I zero'd the X on the DRO with the tool tip touching the stock and on each pass, withdrew the tool with the cross slide and went back to zero on X for the next pass.  I advanced the tool with the compound, .010 on radius on the first 3 passes, then .005 for the next 2 passes, then .0025 for the remaining passes.  260 rpm for all threading passes.   Material is 1215 which does machine quite easily. 


The bore thru the part needed to be 1.40".  Shown is a 1/2" drill about to drill ahead after spotting the part and running a 1/4" drill to 2.5" depth.


Then about to drill with a 7/8" drill.  I slowed the spindle down to 90 rpm for this drill and ran the MQL system.  This helps clear chips and keeps the heat down. 


Then boring out to the 1.40" diameter using a CCMT insert boring bar.  RPM was 450 and again running the MQL system to cool the work help remove the chips.  I took about ..050" on diameter per pass until the last couple of passes.  That worked fine, although there were plenty of hot chips coming off the work!


Parting off using a 2mm insert type parting tool.  RPM was 260 with the mql system running.  Parting off went fine.  I parted off about .010" long so I could turn the end to exactly length and get as good a finish as possible.


And the adapter finished with respect to the lathe work.  Pix 1.


Pix 2, the parted off end.


The adapter being started into the lathe spindle.


The adapter shouldered up in the spindle!!  Success!!!!!


Rechucking the piece in the 4J and trimming off .010" to bring the adapter to the exact length required.  Note the use of the AL jaw protectors to avoid marking up the OD.


Over to the mill to put in the bolt pattern on the backside of the adapter.  This requires 3 holes at a 1.812 BC, 10-32 drilled and tapped 5/8" deep.  I used xy coordinates to spot the bolt pattern after zeroing up the part under the mill spindle using a DTI.  This is after spot drilling.  Starting to drill the 3 holes with a #20 bit for 50% threads.


Tapping 10-32 by kicking the mill out of gear and hand rotating the chuck into the work piece while lightly following it with the spindle feed handle.  This process always works well for me.


Finished part on the print.  1st pix.


Finished part pix 2.


Adapter with collet closer drive plate installed.


Assembled in the lathe.  This is what stays on the spindle all the time.


One of the necessary assembly operations is that the drive plate needs to be centered on the bore.  Here I'm using a DTI to get the runout as low as possible.  I got it within .002 and called it good.  I might go back and work on that again but I might need to slightly the holes in the drive plate as it seemed like I was up against the screws when I get it as close as possible.


And finally, at long last, the level collet closer fully installed back on the lathe!!


So this was quite a relief to get this done!  I really missed not having a collet setup as I use it all the time.  Making this part was quite a challenge for me there was no way to do a trial fit on the threads, but I did manage to come up with a way to accomplish the task.   As my old business partner would say, I can now graduate from a trainee-apprentice level 4 up level 3, provided I can pass the written test giving in downtown Kabul in 2022!

All for now.

Enjoy!

Mike
MIke
Wichita, KS, USA

Offline steamer

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Re: Royal 5C lever collet closer failure and repair, hopefully
« Reply #11 on: February 21, 2019, 11:30:49 PM »
that's looking great Mike!   Congrats!!!

Thanks for bringing us along.   Measuring to wires is an important, and often avoided technique, and it's good to see it get some "press"

Dave
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Damned ijjit!

Offline Neil-Lickfold

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Re: Royal 5C lever collet closer failure and repair, hopefully
« Reply #12 on: February 22, 2019, 12:18:44 AM »
Awesome photos and documenting the build repair process.
Neil.

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Re: Royal 5C lever collet closer failure and repair, hopefully
« Reply #13 on: February 22, 2019, 01:20:12 AM »
Very nice result Mike. Great pics and documentation also.

Bill

Offline Dave Otto

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Re: Royal 5C lever collet closer failure and repair, hopefully
« Reply #14 on: February 22, 2019, 01:45:41 AM »
Nice repair!

Dave