# ER-40 Collet Chuck(s)



## stevecmo (Jul 29, 2012)

OK, this is my first real project.  Actually the first one was a combination carriage stop / dial indicator holder that I needed for the collet project.  My Logan lathe is kind of an odd ball in that the spindle doesn't have a taper.  It's just a straight bore at a little over one inch diameter.  After researching quite a bit I felt that an ER-40 was probably my best option.  I've seen Bob Wright's version and Jim B.'s but as a relative newbie to this wasn't quite ready to jump in.  Then I talked to Jan at Tallgrass Tools and he made me a "kit" with all the raw material, a set of drawings and instructions.  

The drawings and instructions were actually for two different designs.  One used a purchased closure nut which meant the chuck had to have metric threads.  The other design used Imperial threads and a fabricated nut.  After studying the drawings I felt like the fabricated nut was a little beyond my capabilities.  So I bought a couple of change gears that would allow me to cut the 1.5mm pitch metric thread and purchased a nut and a few collets.  

I didn't get many action shots but here's one where I'm drilling the body so I can get a boring bore in:




This project had a bunch of first's for me; my first metric threads, first internal threads and first taper.  They all went pretty well.  Here's the final result:





I had a piece of 2" round stock laying around and thought what the heck, I need the practice.  So I decided to attempt the other version.  I made the body out of the round stock but still had the piece of hex from the kit to attempt the nut.  It was a little tricky because of the "reverse" taper for the nose of the collet and the eccentric ring that lets the collet release from the nut.  But......it turned out pretty well and actually works.






After a little tweaking, both versions have a little under .001" run out.  I was happy.

Thanks for looking.

Steve


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## Charley Davidson (Jul 29, 2012)

Nice job, I need to make an adapter for my surface grinder and will have to do about all the same operations as you did. Thanks for the inspiration.  I've also been contemplating making a couple collet blocks


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## PurpLev (Jul 29, 2012)

real nice work. for lack of materials, I opted to purchase the chuck, and mount it to a back place :/ not as sleek as your version, but at least it works very well.


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## stevecmo (Jul 30, 2012)

Thanks for the comments guys.  It was a rewarding project.


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## dustooff (Aug 29, 2012)

Hi Steve,
it all looks great to my untrained eyes.
Can you explain how you cut the taper for the collet in some detail?

regards
Andrew


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## ozzie46 (Aug 29, 2012)

Nice addition to the arsenal there. 

  I have some ER type collets I've been wanting to make a chuck for. Will get to it some day.

  Ron


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## 8ntsane (Aug 29, 2012)

Steve
Your collet closer looks like it came very well, considering you were doing alot of things for the first time.

Real nice looking job  :high5:  :thumbzup:


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## stevecmo (Aug 29, 2012)

dustooff said:


> Hi Steve,
> it all looks great to my untrained eyes.
> Can you explain how you cut the taper for the collet in some detail?
> 
> ...



Andrew,

I'm not exactly sure what you're asking but I'll try to tell you what I did.

First I installed the four jaw chuck on the lathe and chucked a short piece of 3/8" drill rod and dialed it in concentric.  Then I slid the 3/8" ER-40 collet onto the drill rod.  The 3/8" is arbitrary - you could use 1/2" or whatever drill rod / collet combo you have.  The taper is supposed to be 8 degrees, so I set the compound to 8 degrees as a starting point.

I removed the tool post from the compound and mounted a dial indicator on a mag base.  Then it's just a matter of running the dial indicator up and down the taper of the collet and adjusting the compound until the dial doesn't move.  It will take a little time to get it right and you need to check again after you tighten the compound as tightening it may move things a little.  Just take your time.

Then use a boring bar to bore the taper.  When you get close to the size you need, put some dykem in the taper, insert a collet and gently turn it about a half turn.  Pull it out and see how the contact is.  If you set the compound angle correctly you should get a nice, even transfer to the collet.  If you need to adjust anything (compound angle) now is the time.

Hope that's what you were looking for.

Steve


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## stevecmo (Aug 29, 2012)

ozzie46 said:


> Nice addition to the arsenal there.
> 
> I have some ER type collets I've been wanting to make a chuck for. Will get to it some day.
> 
> Ron



Ron,

It's nothing compared to your 5C chuck, but does the job.  Thanks!


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## stevecmo (Aug 29, 2012)

8ntsane said:


> Steve
> Your collet closer looks like it came very well, considering you were doing alot of things for the first time.
> 
> Real nice looking job  :high5:  :thumbzup:



Paul - thanks for the kind words!


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## porter_jamie (Sep 22, 2012)

impressive work! this has given me an idea for my old black and decker valve grinder. it has some wierd kind of double angle collet which i cannot find stocked anywhere in the country, even the specialist supplier i called offered to buy the only one i had! i i could convert to ER type (probably ER32 or even ER16 would do it) i would have plenty of collets for all the sizes i need. 4 valve motorcycle valve stems are tiny, and my collet is good for 6mm to 8mm


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