# Building an ER collet chuck from scratch for a Myford ML7



## arnoldb

Following on from my own research, questions asked (and answers received - Thanks Guys) in this post, and some other considerations - _mostly related to personal finance and the backward location I live in_ (*), I have decided to build my own ER type collet chuck for my Myford lathe. 

This is not the easiest (nor necessarily the best) option, but will provide me with some additional machining skills, personal satisfaction, as well as stress relief, and hopefully, a usable tool as an end result. If this "quest" adds to anybody else's knowledge, or serves as a spark of inspiration for someone, that would be an incalculable bonus.

I have not yet decided on a specific ER size, but it will either be ER25 or ER32. I need to see what size collets local suppliers here in Windhoek can get - if they cannot or are not prepared to get collets, or those are too expensive for my budget, I'll make those as well.

So, how can I start on a collet chuck without knowing the sizes ? - well, I will need to machine most of the chuck on my lathe's spindle, so the first step in making the chuck, irrespective of size, would be to machine it's spindle mount in raw stock. Not being an entirely competent machinist yet, I decided the easiest way to accomplish this would be to make a clone of the myford's spindle nose first, and as accurately as I can, to use to test the collet chuck-in-making's mounting. If you want to propose Ebay, Chronos et al at this point in time for a solution, please refer to (*) above... No offense intended  As a bonus, I'll have a spindle nose adapter for use in other projects.

Right, rules of engagement laid: Make a Myford spindle nose adapter.
I used a piece of "suitable" HRS I had available to do this; the metal used is not critical (I think ??? ). This was chucked up (I used my 3 jaw chuck's outside jaws, as one of the inside jaws has a broken inner tooth, and grip would be border-line - or break more teeth):






This lot was very gently faced off without tailstock support to just beyond the bandsaw marks with a very sharp toolbit, then center drilled so I could add tailstock support.
Then I took a "deep" (for me) 30 thou" cross cut with the tool bit set at an angle that would "undercut" the scale and rust - saves effort on sharpening the cutting bit  - and immediately cleaned all the swarf from the lathe-ways and slides - the scale works like grinding compound on the lathe's sliding surfaces.

After this some plain turning to get to dimensions - this metal is horrible to get a nice finish on!:





I left the register part 1/2 thou oversize - to work down as needed, as this is the most critical. Then I needed a 55 degree thread cutting bit, which I didn't have, so I just free-hand ground one for my "semi-quick-change toolholder" from 4mm round HSS, checking with a fishtail to get the correct angles:





.
After grinding, I just moved it further into the holder to minimise overhang and "sproing" 

Then set up the change-wheels on the banjo for 12 tpi for the thread cutting part. Apologies to everyone who knows this, but maybe someone can appreciate the following: Use a strip of paper while pushing together, and turning, the gears manually to set gear spacing - feed the paper in while turning the gears, and when it passed through, just tighten up the banjo (or gear stud mounting) - And DON'T forget to add a drop of oil to the gear studs/runners and gear teeth!:





Humble pie - I forgot to take photos of the next steps.... :hDe: - well, I simply got busy...
I first turned a groove for thread run-out next to the index ring, and spent many back-and-forths to thread the nose. Somewhere along the line, I think some dirt got stuck in the Myford's clutch (How do you people do single-point threading without a clutch ??? ???), causing some creep even when the clutch was disengaged (or should that be engaged??) Luckily, this was an imperial cut, so, for the first time since I've had my lathe I could use the thread dial indicator and disengage and engage the leadscrew as needed - MUCH easier than doing Metric threads on the old girl 

After turning and cleaning up the threads, I tried screwing on my 4 jaw, as well as dog-plate carrier. The last went on smoothly, but the 4-jaw refused, so I used engineer's blue (a.k.a. Prussian blue) to check for the problem. I know my 4-jaw is the tightest on the lathe's own spindle, so if that can fit, everything would be sort of OK. The blue showed the register was still too big, as I intended, so I used some oil-coated 320 grid sandpaper (Thanks Tel!) to get rid of the oversize. - the 4-jaw ended up screwing on with <approximately> <exactly> the same "feel" as it does on the lathe spindle - that should be good enough for now:





The results of this afternoon's work:




and





Regards, Arnold


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## RobWilson

Looking good , Thm: great finish on the screw cutting


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## zeeprogrammer

That looks production quality Arnold.
Very nice.
Methinks you've been holding out on us.


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## Lew Hartswick

That is the tool post on our lathes at school. I think that would be a good design 
for home built quick-change post. No dovetails just 90deg Vs. They are really
sturdy.
  ...Lew...


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## SBWHART

Hi Arnold

Comming along nicely

http://www.arceurotrade.co.uk/Catalogue/Collets/ER-Collets-Collet-Chucks 

This link has good info on the ER32 collet system sizes etc

Have fun

Stew


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## arnoldb

Thanks Rob  - had a brownie moment earliesh on in the cut; slightly too deep feed and broke the very tip off the cutting bit; Quick regrind & hone, and popped back in QC post - picked tread up right away & continued.

Lew, the toolpost is an Asian import I was able to find locally - Somebody ordered it, but it was too small for their 2.5m lathe and the supplier got stuck with it - I had to make a couple of changes for it to fit on my lathe as it is actually slightly too big - but it works very well. I just need to get/make more tool holders 

Zee, as to holding out - Nope - Really not! You can do it as well. I follow a couple of basic rules (very sharp cutters ground for the material at hand, sensible speeds - if in doubt, reduce speed, etc), and make each cut count and as accurate as I can. The rest then comes by itself - after some Emery & Oil :big:.

Thanks for the link Stew  

Regards, Arnold


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## Nick Hulme

Looking good, 
Nick


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## arnoldb

Thanks Nick 

At last, some more progress.

I found a supplier in South Africa that is willing to ship me tools for a very reasonable fee to Windhoek. Stretched my budget, and ordered a set of ER25 collets from them, as well as a closer nut with integral bearing.

Visited the local engineering firm where I can buy odds 'n ends on Monday, and got a nice bit of cast-iron off-cut from the storeman. Showed off the "Fancy" I built to them, and with the storeman and the sales staff (as well as some of their engineers) surprisingly impressed, got a whopping discount.
What I ended up with was this lump of 200mm long 55mm diameter cast iron:





As one end of that had been machined in a lathe before, I marked and center drilled the other end, chucked it up and took off the skin part-way with a deep undercut, as well as faced the end to close to the tailstock support:





I calculated overall chuck length would be 60 mm - to allow for the spindle end, length of ER collet needed and about 5mm extra for good luck. Then onto the bandsaw to cut a piece at just over length:





Then mounted the four-jaw chuck, and centered the piece in it as closely as I could. (Twice... :wall: The first time I forgot to check that I put the faced side into the chuck. Not being any good at gambling, of course I lost the 50/50 odds and the sawed-off face was on the chuck face first time round...)
I used the 4-jaw, as I could get the most grip support from the jaws; the rest of the machining would be mostly without tailstock support. Then faced off to get the sawed face square and to correct overall length:





As the Myford has a ~16mm spindle bore, I then used progressive drill sizes to drill through up to 16 mm - this is just below the 17mm minimum size needed for the ER25 collet chuck:





Then the CI was further bored out to a depth of 30 mm for the inner diameter for the 1 1/8" x 12 tpi thread, and a home-ground bit used to make a 3mm deep undercut at the maximum depth for thread run-out. I then ground and honed the other end of the same bit into a 55 degree threading point, and started threading. Note that the threading bit is turned upside-down, and that I am cutting on the back of the workpiece on infeed, rather than at the front. This just makes life easier for me  :





And finished thread:





After this, I carefully bored out the register to size, and screwed in the spindle-nose replica I made earlier. This was a big moment... will things be OK? Mounted my best dial indicator to test run-out on the spindle replica.  ??? - dial indicator must be broken; it doesn't change when I turn the whole lot through a couple of turns - just vibrates slightly ;D - I think that's a good result. Setup to test run-out:





And where I stopped this afternoon:





Tested some more by screwing onto my dividing head - slightly too tight. A check with engineer's blue shows the register is OK, so the threads are the culprit. I'll just make a tap to clean out the last bit of tightness later on.

Now I have to wait for delivery of the collets and closer nut before I can continue; it would be best if I have those for the next steps.

Regards, Arnold


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## GailInNM

Thats some very good precision work.  :bow:
Gail in NM


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## RobWilson

Hi Arnold , looking good :bow: :bow: :bow: great finish 

Regards Rob


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## CrewCab

Nicegoing Arnold 8) ........... keep us informed  ;D

CC


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## arnoldb

Gail, Rob & CC - Thanks guys 

Have to wait for the collets & nut to arrive; might be a week or two (or more  ). For now, I'll be doing some other tooling - already started on something using the spindle nose replica I made for the collet chuck  - and I'm itching to build another engine as well.

Kind Regards, Arnold


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## PhiberOptix

Looking great Arnold

keep letting us know how it progresses m8

regards
Andy


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## CrewCab

arnoldb  said:
			
		

> I found a supplier in South Africa that is willing to ship me tools for a very reasonable fee to Windhoek.



Good to hear you've found a local"ish" supplier Arnold, hopefully this will make life a lot easier 8) .......... providing Shrek leaves you enough limbs to work with ;D

CC


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## arnoldb

Thanks Andy & CC 

I have not received the collets yet, but started on a use for the spindle nose clone I made.
I regularly need to do some indexing, and setting up the vertical slide, and dividing head can be a pain sometimes. Also, I have been abusing my dividing head for jobs i'ts not really built to do, so I'm using the spindle nose clone for a quick-mount indexer that I can fit on the cross-slide with minimum fuss, and easy to get square.

While the chuck-in-making was still mounted in the 4-jaw, I screwed in the nose clone, and turned down the back side to 22mm. With some odds 'n ends from available material - also turned down a bit to get rid of scale and to get things square, I ended up with this lot:





This is "sort of" how things will go together - some welding, drilling, tapping, slitting, boring and more parts required:





CC, as you mentioned Shrek - he's been a pretty good birdy of late - no blood for the last couple of months. I think he noticed I was slobbering over the Arc Euro Trade catalogue - so he tried ordering some bits for me - fortunately I got to him before he got to my credit card :big: - I don't need a shredder :





Regards, Arnold
Edit: More build info/pictures are here


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## CrewCab

arnoldb  said:
			
		

> I don't need a shredder :



So I see 

CC


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## arnoldb

Well, had a most productive day today _producing scrap_.

I received the collets and closer earlier this week:





The collets looks OK - I'm slightly disappointed with the closer; it's pretty rough, and full of very sharp edges, so I'll disassemble it and get rid of the sharp edges and see if there is any dirt/swarf in the bearing.

On to today's work. I screwed the chuck body onto the lathe spindle, and turned the nose down to start threading for the 32mm x 1.5mm closer thread.
I took the next photo just before I used a parting tool to make a groove for thread run-out:





Then started threading - was coming close to final size and then disaster - cut half of the formed thread away :wall: :wall: :rant: :rant: :redface2: :redface2: 





I think the topslide moved - don't know if I accidentally brushed against the dial or what. I was turning the thread using cross-slide feed only - still need to make some clamps and additional markings to use be able to use the offset topslide method, as mine can't rotate enough... 

So that's one chuck body scrapped - might be useful for something else in future.
Then I did something I never do - went into the house, got a beer to cool me down, and brought it back to the workshop to think. Must have still been fuming when I fetched the beer, as I can hear Shrek practicing new words while I'm typing this lot up... 

On to recovery. One thing I have learned through this (besides to make a plan to lock the topslide :-[ ) is that my original choice of cast iron might not be the best. I noticed some "chipping" in the spindle thread lead-in, so this piece of CI I have might be too brittle ??. This could potentially cause long-term problems with the much finer closer nut thread. I have an old bolt - used to have a pair of them but the other one was already turned into other tooling. This is nice steel of unknown origin, but it does machine OK:





Shoved that on the bandsaw to get a new body, and gave the lathe a good cleaning while the saw was doing it's job:





Fortunately, I now have all the cutting bits and steps, so next one might be easier ;D
As I had an open beer, further machining was out of the question, so I closed up shop for the day. Tomorrow is another day....

Regards, Arnold


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## zeeprogrammer

Sorry to hear that Arnold.
This is a good thread. Great detail and I'm learning a lot.
Thanks.


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## arnoldb

Thanks Zee.

This just proves I have a wall of learning too, and not afraid to hide it :big:

Kind regards, Arnold


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## deverett

Arnold

A good job coming along with your collet chuck.

You were too quick in ordering the collets. I have just received permission from an ex-Cape Townian to publish his email address on how he made his collets. Me being away from the computer for a while and emails between me and Hubert gave you a head start!

Hubert's address is  [email protected] Hope showing this doesn't go against the rules of the forum.

He has recently completed making his own lathe and is kitting it out with mostly home made tooling. A fine piece of work he is making of it too. Something to do with the southern hemisphere air for you machinists?

Dave
The Emerald Isle


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## arnoldb

Thanks Dave, I'll pop Rudy a mail  - Must be the air here, or some psychological remnants from previous years where we were all very limited to imports into these part of Southern Africa :big: (and that's enough said  )

Well, new start today...
Cleaned up the new chuck body:






Then switched to the 4-jaw and drilled consecutive through-holes to 16mm, and tried my hand at an action shot while drilling on fast back-gear to 19mm (my biggest drill) to spindle-depth:





And bored the register to size using a carbide tipped bit that I honed on a bit of emery:





After this I bored out for thread run-out in the back; slowest back-gear speed & PLENTY of lube with frequent stops to clean out the swarf ribbon. Thought it might be more difficult, but came out well. Then I set up the change wheels for the internal thread, and set up for the single-pointing. Decided to stop there, and do the thread tomorrow when I'm fresh.

Regards, Arnold


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## Majorstrain

Nice work Arnold,
Thanks for throwing out your first chuck so I could catch up. :big:
I'll try not to return the favor with my chuck body when I get to it this week.

Cheers
Phil


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## ariz

excellent work arnold, and a very wise decision to postpone the difficult part on the next day, when you're fresh

I made so many errors in the late evenings, wanting to complete a job, instead ruining a long work!


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## Blogwitch

I should have mentioned this a little earlier Arnold.

When cutting an internal fitting, you should really cut the thread first. Then once the thread fits perfectly, by boring to almost thread OD, you can start to check for register fitting.

It is the opposite when making a spindle nose. Turn the register to perfect fit first, but overall length of the nose. Then cut your thread on the end.

It makes everything so much easier to do and check.

Blogs


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## arnoldb

Phil, Ariz, Blogs - thanks for the responses 

Phil, please do catch up & pass me, then you can post a how-to, so I can stop bumbling along setting a bad example :big:

Ariz - yes, sometimes it is better to wait. I've botched a good few things by rushing :big: ; One of the most valuable things model engineering has taught me is patience . 

Blogs, you're right - but the register I turned is ever so little under-size still - will need to bring it to size with emery later on. I Went this way around this time, as the steel I'm using here insists on coming off in ribbons - which would have made the tread run-out undercut very difficult, and the long threading a real hassle with swarf getting caught up on the bit while threading...

Fortunately, I am on leave for a change, so hope to have this finished by tomorrow evening; have some other to-dos as well 

Regards, Arnold


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## arnoldb

Well, a good result for a change 

This afternoon I started by turning the spindle thread in the chuck body. A close-up down the register and thread - the pool of cutting fluid in the back is collected in the thread run-out:





Once I was happy the thread was well-done, I unscrewed the 4 jaw with the chuck body still in it and tried to screw the whole assembly onto the spindle from the collet chuck body. The register was a touch too tight, so I turned it around again, and used some emery & oil to open up the register a bit more. With the next test it fit very acceptably.

Removed the collet chuck body from the 4-jaw, and screwed it straight to the spindle. Then turned down the nose end to size for the collet closer nut:





Once again the undercut using a parting tool - slowest back gear speed, as this steel is fairly tough:





Threading nearly done:





I tested the final thread size by trying to screw on the closer nut after cleaning the threads thoroughly on each attempt. Once it screwed on full way, but slightly stiffly, I used a fine triangular needle file just to give the threads a final cleaning - after this the closer nut spun on easily, but not loosely.

Now came time for the internal taper for the collet. I first tried the following to set the topslide to taper:





Something "felt" wrong at this point, so I tested a couple of different collets and got readings all over the show... Ahh... They are all already slit and spring loaded, so there would be differences. I settled on trusting mr. Myford, and just set the top slide to 8 degrees, making sure the boring tool was set dead on center. I know there are other ways to set an accurate angle on the top slide - but was not about to go down that route. A blue test while the hole was still slightly undersized would suffice, and that's what I did, using the 10mm collet and a known-good piece of 10mm silver steel, long enough to be clamped on it's entire length. First off, blued the collet and inserted in closer, then inserted test bar:





Then screwed the collet up tight into the chuck,carefully keeping the collet from touching the chuck initially and keeping it from rotating as I did this. Reversed out the collet, once again preventing rotation and trying not to let it "drag" in the chuck - got the following blue marks in the chuck proving that the entire lenght of the collet was clamped adequately and evenly:





After this I turned the taper to just under full-size and carefully smoothed it off using some emery superglued to a wooden dowel & oil. Then I played around with removing the chuck, installing it, chucking up different workpieces repeatedly in different rotations and a whole combination of the previous. Biggest run-out I measured was less than 0.005 mm (less than half a division on my 0.01mm guage) - that's about 0.2 thou - I think that's acceptable.

Some cosmetic work externally (well, it's not a beauty ) and here is where I left off for tonight:





Tomorrow I'll cross-drill a couple of holes to take a tommy bar in the chuck body, as it is too smooth. At a later stage, I'll knurl a ring grip on the body as well; first need to get some knurling wheels and build a tool 

So, that's my version of a collet chuck; pretty it's not, but I really think I'll enjoy this addition to my workshop in upcoming projects.

Kind Regards, Arnold


PS: I'm having a double whammy on the VSOB bottle tonight. Firstly, Congratulations Mate ! - up to you if you want to tell everyone or keep mum  ; the other reason is pretty obvoious from the above ;D


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## mklotz

Congratulations on a job well done and a very informative write up. I did the same thing for my (non-Myford) lathe when I was starting out so I can really appreciate how chuffed you must feel about pulling this off so successfully. Picture me lifting my glass to you later tonight.


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## GailInNM

Very well done, Arnold. You will really enjoy using it.

I know that you have followed some of my threads, so you know that I use collets for most of my lathe work. Mine are 5c that fit the lathe spindle, but I also have a ER32 adapter for odd size work. You have the extra pleasure of knowing that you made yours. I made one years ago for another lathe, but it was not the quality yours is.

 :bow: :bow:
Gail in NM


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## RobWilson

Very nice work Arnold :bow: :bow: :bow: :bow: looks like it will be a well used tool in your shop Thm:
looks like i will have to get my finger out and make one ;D



Thanks Rob ;D


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## arnoldb

Marv, Gail - I feel a bit overwhelmed!

Thank you both VERY much - I've learned a massive amount from both of you, and consider you as premium mentors. To receive such positive feedback from yourselves is very special, and I will be lifting yet another glass tonight.

Sincerely, Arnold


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## arnoldb

Thanks Rob ;D

You know it will be well used :big:
Now beware what happens when you use too much violence when your finger is in the wrong place Rof}

And of course you need to make one! :big:

Regards, Arnold


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## Majorstrain

Positively magnificent Arnold, Thm: th_wav



> pretty it's not,


Mate I think it's a work of art, the beauty is in the accuracy not just the looks.
You have taught me heaps in this thread about procedure and test fits. :bow: :bow:

Thanks to all the other guys for their input as well, Arnold is not the only one you've helped on this tool making adventure.

Hope mine comes out half as good as your's Arnold.
Cheers
Phil

p.s. Mate I'm still excited, *that chuck is just excellent!* :bow:


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## zeeprogrammer

Thanks for that thread Arnold.
I think it will help a lot of people (me!) believe they can make tools like that too.


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## arnoldb

Phil, Zee - Thank you 

Phil, I'm sure you can also pull it off successfully  

Zee, of course you can make tools like this - the biggest hurdle to overcome is self-doubt. And while it is "just" a tool, like Marv said - I feel chuffed; building it was fun has given me a great feeling of accomplishment.

I didn't do much in the shop today, but managed to squeeze in time to drill the chuck for the tommy bar, and also made up a matching tommy bar and c-spanner from some 6mm silver steel. For the c-spanner, I turned the tip of the length of silver steel down to 4mm. After this, I bent the curve in around a piece of 30mm rod - when I released the tension after bending, it sprung back to a nice fitting curve for the collet nose. Bending the silver steel was pretty tough going, and it got pretty warm from internal friction!
Then I picked up a scrap piece of flat iron under the bandsaw and drilled a 4mm hole in it at a slight angle, and silver soldered it to the bent drill-rod to make a nice hook. Used the bench grinder to grind the lot to a reasonable shape, and finished off with a file and then sandpaper.

I also turned 2 pieces of 10mm aluminium rod into a matching pair of handles, and loctited those to the c-spanner and tommy bar:





Now all that is left, is to make a nice wooden storage case for the chuck, accessories and collets - this I'll do in the next week or two when I plan to do some work on my kitchen cabinets - I can do OK woodwork, but don't like the mess, so I'll lump all the woodwork together in a single go.

Regards, Arnold


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## Majorstrain

Hi Arnold,
Finally finished my ER32 collet chuck woohoo1 woohoo1 

Mate, thanks heaps for your thread. :bow: :bow: couldn't have done it without your instruction and examples.

I finished mine a couple of nights ago but couldn't get if off the lathe spindle :wall: Dam it had worked itself on tight, and bling boy here had made the finish too smooth for anything I had to get a grip. Needed to wait and get a strap type pipe wrench from work to get it off.
The last thing to do is put the C spanner slots in it. Run-out is 1/10 of a thou near the collet but a bit worse further out.














Great to see you have used yours in the build of your tiny.

Thanks again Arnold.
Cheers,
Phil


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## Paolo

My compliments..Really well done! Well proportioned...nice to have...
Best regards
Paolo


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## arnoldb

Hi Phil - Great work Thm: - very well done

Hope you get as much fun out of yours as I've had so far 

Better get some holes cross-drilled for easier removal 

And thank you very much for the "thank you" 

Kind regards, Arnold


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## GailInNM

Very nice Phil.
And another Thm: to Arnold for his.

Gail in NM


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## clifwst

I know this is an old thread, but it was very helpful to me when I turned my ER32 collet chuck for my Atlas 618 lathe. 

I had the armstrong spanner, so I turned the OD to fit. It turned out to be 2" diameter and just over 3" tall.

The resemblance to the chuck by majorstrain is intensional, when I searched the internet for how to make the chuck, his was the one I liked the most.

Thanks again for all the help this thread gave me


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## Blogwitch

Another one by myself shown on another site.

http://www.modelenginemaker.com/index.php/topic,1411.0.html


John


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## ShopShoe

Since this thread has been bumped, I will add that I have made an ER11 collet chuck following these steps almost exactly and it worked well.

(Why ER11?  I wanted a way to mill and drill in tight quarters where a drill chuck or endmill holder wouldn't reach. It works very well in both lathe and mill and, as best as I can tell, it has very little runout. I hold it in either machine with a collet: MT3 in the lathe and R8 in the mill.)

--ShopShoe


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