# ER40 Adjust True Camlock Collet Chuck Build



## davidpbest (Aug 26, 2017)

Earlier this year I purchased an ER40 collet chuck with integral D1-4 mounting from hhip.com (their part #3901-5042).   I wasn't completely satisfied with the quality and it didn't have sufficient stick-out from the spindle nose to get cutting tools to it using my solid tool post.  I also had inconsistent registration to the spindle with unacceptable TIR.   This is that chuck.







I decided to replace it with a better solution - one that was adjustable to the centerline of the spindle rotation, along the lines for an Adjust True or Set Tru scroll chuck.

After some research I bought an ER40 plain back collet chuck from an eBay seller, did some checking of it when it arrived and concluded it was built to decent tolerances.   Then I bought a Bison D1-4 camlock backing plate, some 1045 stock from McMaster and set about making a sleeve to join the Bison backing plate to the ER40 collet chuck.   

This is the result - it has four M8 set screws around the perimeter that can be used to precisely center the chuck.   I'm very happy with the result.






Here's a nose-on view - you can see the centering adjustment set screws if you look closely.






Although a bit expensive, the Bison D1-4 backing plate is exactly what I expected  - outstanding quality:






I'm attaching the drawing for this implementation in case anyone wants to do the same.   

Also, there are more images and description of the build process here:  

https://flic.kr/s/aHsm1PtHsq 

Hopefully this will be useful to someone here.   Enjoy.


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## pstemari (Aug 26, 2017)

Nice job! 

Sent from my Pixel XL using Tapatalk


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## ACHiPo (Aug 26, 2017)

Really impressive.   Nice work!


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## T Bredehoft (Aug 27, 2017)

An excellent design, thanks for sharing. I'm pleased with the versatility of the ER40.


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## richl (Aug 27, 2017)

I luv that you did this! Don't know that I'm up to it, but it's great you posted this for guys like me.

Rich


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## frugalguido (Aug 27, 2017)

I still am amazed that one of the better quality tooling outfits I.E. Maritool, hasn't made a high quality D1-4 ER40 chuck. That hhip is pretty poor inconstant quality, some say that it meets their stated spec (which is constantly changing by the way, for the worst) to mine that doesn't meet it at all.

Very nice job on your design! Mind giving us the seller details and part #'s for the purchased items?

Just noticed that you did give us the info in the photo stream, thanks!


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## petertha (Aug 27, 2017)

Very nice! I want to use this principle on some similar applications. So if I understand the sketch, you
- snug the X axis cap screws so the ER plate so its is flush but still adjustable
- adjust the 4 opposing set screws so it runs concentric
- lock the cap screws down so assembly it stays put

Brand comment FWIW. Most of my rotating tooling is Bison purchased years back. But it has become stupidly expensive in Canada. I needed some small diameter chucks for my rotary table so took a shot with Gator brand. I figured I'd get a D1-4 backplate for the lathe thrown in. Its the kind you machine the lip to suit the chuck recess & that operation went fine. I was also interested in a repeatability test between the Gator & Bison back plate (meaning how it aligns to lathe spindle nose). Maybe I got a good one because I could not measure any concentricity deviation using 0.0001" DTI. I also have a Bison 5C collet direct mount (non Set-Tru). Rather curious, but it favours a certain pin alignment over another. Not a huge amount, but its there & repeatable (using Bison brand 5C collets). In hindsight I should have got Set-Tru. When I rotated the Gator D1-4 backplate to different pin/hole positions, nothing changed, same concentric reading.  I don't think the pins have much to do with it as long as they are seated properly & the cams can pull it into the nose snugly & equally. Seems like grinding accuracy of nose taper is the critical thing?

You probably now this but it was news to me. To get the runout specs quoted on ER4 collets, it takes a surprisingly hefty torque rating. I'm probably overly squeamish but do you put the lathe in low gear to tighten/untighten the ER collet cap?


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## Tozguy (Aug 28, 2017)

I have found it necessary to use a pin wrench (or box wrench depending on the ER chuck) when tightening ER32 collets. David, there seems to be a pin wrench hole in the first chuck pictured?


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## davidpbest (Aug 28, 2017)

Tozguy said:


> I have found it necessary to use a pin wrench (or box wrench depending on the ER chuck) when tightening ER32 collets. David, there seems to be a pin wrench hole in the first chuck pictured?



Yes, there is a pin wrench hole on the perimeter of the ER40 chuck I used, but of course it's covered up because the rim of the chuck is now recessed into the adapter sleeve.   And I agree that considerable torque can be required to tighten the ER40 collet sufficiently, and I have come to the practice of using my conventional chuck key in one of the Camlock square locking holes as the opposing lever force against the ER40 spanner.   It would be easy enough to put a few pin wrench holes around the adapter sleeve if you wanted, but I've gotten used to using the square chuck key and actually don't care to introduce yet another tool into the inventory just for tightening the ER40 chuck.   Others may feel differently.

Since I brought up the spanner, there are of course two types - the claw type and the UMW type that encircles the nut and tabs into the slots in about 4 places.   Thus far I have broken two of the claw type because they were cast from pot metal, and now I have a Lyndex that appears to be a forged casting and has stood up so far, although it is light weight and probably wouldn't withstand a lot of mistreatment.   The claw type I like the best is one I made myself from 3/16" steel flat stock (20 minutes on the bandsaw and grinder).   I have two of the encircling type wrenches, both stamped from sheet steel, and of those, the one that I favor is the DZ wrench.

Where I have had more issues is with the ER40 chuck nut.   I now have a collection of about six of them, and most of the imports do not grip the groove on the nose of the collet sufficiently to pull it out of compression when the nut is backed off - the collet simply pops loose from the nut.   This one does not grip the recess on the collet nose at all, which was a big disappointment considering the cost.   The USA made Maritool collet nut doesn't grip the collet nose firm enough to suck the collet out of the taper if tightened to torque spec.  The nut that came with the HHIP collet chuck is total junk IMO.   The nut that came on the the  Shars R8 ER40 collet arbor I purchased is nicely finished, but isn't ball bearing, thus difficult to loosen, and again doesn't grip the collet well enough to retract it from moderate compression.   There are two ER40 collet nuts that I am satisfied with (both ball bearing type), including the one that came on the plain back collet chuck that I adapted, and the Parlec.   The Parlec is closest to the original Rego-Fix nuts I have on other equipment where you press the collet into the nut at a slight angle to engage the retract ring firmly into the groove around the nose of the collet.   It can be fussy to learn the technique at first, but the collet will not come loose from the nut unless it's angled to the side.


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## davidpbest (Aug 28, 2017)

petertha said:


> Very nice! I want to use this principle on some similar applications. So if I understand the sketch, you
> - snug the X axis cap screws so the ER plate so its is flush but still adjustable
> - adjust the 4 opposing set screws so it runs concentric
> - lock the cap screws down so assembly it stays put



Exactly.   I believe that's the way most Set-Tru chucks function for adjusting runout.   The Set-Tru 6-inch 3-jaw scroll chuck I purchased from Precision Matthews (which is an outstanding quality copy of the Bison), has four set screws in the chuck body, that push against a projection on the back plate that's recessed into the chuck body.   When I first tried to adjust it, it wouldn't budge.   There was no tolerance between the back plate projection and the recess in the chuck.   So I simply skimmed off about 0.008-inch of the back plate projection, remounted the chuck and I had the the necessary adjustment capability.   On that chuck, the bolts that secure the chuck to the back plate come from the back plate side.   On the ER40 adapter design I did, the chuck can be secured from the front or back, but I decided to use the front to make it easier to do the TIR elimination adjustments.



> You probably now this but it was news to me. To get the runout specs quoted on ER4 collets, it takes a surprisingly hefty torque rating. I'm probably overly squeamish but do you put the lathe in low gear to tighten/untighten the ER collet cap?



No, I use the regular square chuck key in one of the spindle camlock chuck cam-holes as the opposing force against the ER40 collet spanner.   Low gear isn't enough to lock the spindle when tightening the ER40 collet chuck.


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## Mark_f (Aug 28, 2017)

I'm glad I saw this thread. This design gives me an idea. My ER40 chuck gives .0003 TIR on my Lathe spindle, but when put on the dividing head spindle I get a couple thousandths TIR. I could make another chuck for the dividing head using this principal and use it on the dividing head or either of the two rotary tables and could get it to run true.


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## Tozguy (Aug 29, 2017)

Just a reminder to lube the collets, it might help with extracting the collet when done. This from Tormach:
quote

Lubricate the outside of the collet and the inside of the spindle taper with anti-seize lubricant. These are sliding surfaces and are best kept lightly lubricated. You can use Tormach PN 31273 or any other good quality anti- seize type lubricant. Lubricate sparingly to avoid risk of the lubricant migrating to the inside of the collet.


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## Rich V (Aug 29, 2017)

davidpbest said:


> Snip
> 
> Where I have had more issues is with the ER40 chuck nut.   I now have a collection of about six of them, and most of the imports do not grip the groove on the nose of the collet sufficiently to pull it out of compression when the nut is backed off - the collet simply pops loose from the nut.   This one does not grip the recess on the collet nose at all, which was a big disappointment considering the cost.   The USA made Maritool collet nut doesn't grip the collet nose firm enough to suck the collet out of the taper if tightened to torque spec.  The nut that came with the HHIP collet chuck is total junk IMO.   The nut that came on the the  Shars R8 ER40 collet arbor I purchased is nicely finished, but isn't ball bearing, thus difficult to loosen, and again doesn't grip the collet well enough to retract it from moderate compression.   There are two ER40 collet nuts that I am satisfied with (both ball bearing type), including the one that came on the plain back collet chuck that I adapted, and the Parlec.   The Parlec is closest to the original Rego-Fix nuts I have on other equipment where you press the collet into the nut at a slight angle to engage the retract ring firmly into the groove around the nose of the collet.   It can be fussy to learn the technique at first, but the collet will not come loose from the nut unless it's angled to the side.



David, another great design and execution.

I have the ER32 ball bearing nut from Arc Euro Trade  http://www.arceurotrade.co.uk/Catal...nners/ER-Collet-Nuts-with-Ball-Bearing-Type-B
These are very much like the original Rego-Fix nuts you describe and I'm pleased with the quality and performance.    Arc Euro Trade offers a unique set of ER tooling such as ER collet blocks and a 5C to ER32 Collet Adaptor   http://www.arceurotrade.co.uk/Catalogue/Collets/ER-Collet-Fixtures
I have their 5C to ER32 Collet Adaptor and use it in my 5C spin indexer. Very handy and allows any size piece within the ER32 range to be held vs the narrow holding range of 5C.

For using ER collets on my PM1340 I was lazy and used the "field expedient method" and purchased an ER32 straight shank collet chuck simmilar to this one https://www.amazon.com/Straight-Shank-Collet-Toolholder-Milling/dp/B00N0M1RKM/ref=sr_1_4?s=hi&ie=UTF8&qid=1504027660&sr=1-4&keywords=Straight+Shank+Collet+Chuck  It has a hollow shank that I chuck in my 6 jaw set true chuck. This allows me to true up the ER chuck and I don't need to change chucks.
You design gives more control on axial parallelism, something that I can't adjust easily with just the ER straight chuck.


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## davidpbest (Aug 29, 2017)

Rich V said:


> I have the ER32 ball bearing nut from Arc Euro Trade http://www.arceurotrade.co.uk/Catal...nners/ER-Collet-Nuts-with-Ball-Bearing-Type-B
> These are very much like the original Rego-Fix nuts you describe and I'm pleased with the quality and performance. Arc Euro Trade offers a unique set of ER tooling such as ER collet blocks and a 5C to ER32 Collet Adaptor http://www.arceurotrade.co.uk/Catalogue/Collets/ER-Collet-Fixtures



Rich, I have so many ER40 collet nuts now that I can't remember when one (if any) came from Arceurotrade.  LOL  But I do have their square and hex ER40 collet blocks which I quite like.    I did buy a 3" 4-jaw chuck from them which I'm not impressed with, and a few other items like dead centers, etc. which have been fine.   They do a great job on shipping to the USA - very fast.


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## mksj (Aug 31, 2017)

Nice job David, over the top work as usual and with detailed information. I believe we both have the same ER bearing nuts from Maritool, they are not too common. They work well, just be aware that if you compress a collet to its specification limits, the bearing nut is more likely to fail. I already returned an ER40 nut to Maritool for a replacement a while back, this prompted me to get a fractional 1/32 ER40 collet set and also a 10 and 12mm collet for my indicators. If you look at the better quality collets, you will often see deeper cuts in the splining which probably allows them to compress further and more uniformly. 

https://www.maritool.com/Tool-Holde...438/ER40-BEARING-COLLET-NUT/product_info.html


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## Kamloopsendo (Sep 18, 2017)

davidpbest said:


> Earlier this year I purchased an ER40 collet chuck with integral D1-4 mounting from hhip.com (their part #3901-5042).   I wasn't completely satisfied with the quality and it didn't have sufficient stick-out from the spindle nose to get cutting tools to it using my solid tool post.  I also had inconsistent registration to the spindle with unacceptable TIR.   This is that chuck.
> 
> View attachment 240557
> 
> ...


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## Kamloopsendo (Sep 18, 2017)

David:  I never fail to be impressed with the stuff you both post and produce.  I did acquire a PM1340GT lathe which is still not running due to the hassles associated with getting the VFD up and running (another story).  I noted your posts as I'm looking at a collet chuck as something I'll have to acquire although I'm sure hoping I can find something off the shelf, if not your chuck looks GREAT.
Alex


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