Where to buy 6.5mm ER40 collet?

[HollowpointParticipant @hollowpoint]

I have a requirement to hold 6.5mm as accurately as possible.

Does anyone know where I might be able to get a 6.5mm ER40 collet?

Typically, a 7mm collet would normally be used as they collapse down to 6mm. However I have found that the more you squeeze the collet the worse the runout gets. The same 7mm collet that holds 7mm to less than 0.01mm won’t hold 6.5mm at less than 0.02mm. Normally that would probably be ok, but I need to be as accurate as possible in this instance.

Thanks in advance.

 

[JasonBModerator @jasonb]

https://www.zedaro.com/products/0645151 or your local rego-fix supplier such as Brunner in the UK

Alternative is to bore your own split bush or soft jaws in-situe.

[EmgeeParticipant @emgee]

ARC Eurotrade do ER40 imperial collets so 1/4″ (6.70mm) will probably suit your needs.

Emgee

[JasonB]

On JasonB Said:

zedaro.com

That link is worth saving as it has some history of ER collets as well as the applicable DIN standard.

[Emgee]

On Emgee Said:

[…]  so 1/4″ (6.70mm) will probably suit your needs.

Count me confused

MichaelG.

[Trevor Drabble 1Participant @trevordrabble1]

Coventry Collets are a collet manufacturer , so maybe they could be of assistance.

[Ex contributorParticipant @mgnbuk]

1/4″ (6.70mm)

1/4″ was 6.35mm last time I looked, so a 6.5mm workpiece might be a bit of a snug fit.

Nigel B.

[EmgeeParticipant @emgee]

Apologies to all concerning my error, don’t know what to blame for such a mistake other than I clearly didn’t give it enough thought..

Emgee

[Neil LickfoldParticipant @neillickfold44316]

Depending how long the part is, an ER40 may not be the best collet to use. 5C or similar will be better for short pieces, like less than 1 diameter long.

There are other collet types that are better holding as well, ones that have a shallower taper in the body, like the OZ collets or the BIG Daishowa collets.

Then if you need to be using an ER40 collet, buy a good quality ER40 collet in Ø6 mm or 1/4 inch, then set it in place with pin to ensure that it is running true. Not very tight in the holder, using an undersized pin, like 5.97mm for example. After taking the pin out, use some thin super glue to hold it all in place. Then either grind or turn it out to finished size with a sharp boring bar. Iscar make some really good bore bars for small holes, like 6mm for example. It will bore 36mm deep which is longer than what most ER40 6mm collets are with their small hole length.

Then soak in Acetone to dissolve the super glue or boil it all with soapy water will release the super glue. Mark or ID the radial position that the collet was in, and it will be as accurate as you can have on your setup.

When holding short pieces in ER40 collet at work, I have a support plug in the back of the collet at the same diameter as the part being held. It prevents the back from collapsing, and then allows the front section with the 30 deg taper to collapse a little bit to hold the part well. I find it rare that an ER40 collet will hold a part dead true from the initial closing. Usually it will to be lightly tapped to get it to be very true. Often it is within 0.02mm but not 0.005mm true.

The Big collets will hold a nominal diameter on initial clamping better than 0.005mm TIR right off the bat. Often even better if the spindle is any good.

Neil

[HollowpointParticipant @hollowpoint]

Thanks for the advice guys. I’m gonna try a 17/64″ inch collet first since it’s close in size and it’s by far the cheapest option.

If it’s not good enough, I might have to fork out for the rego fix one. Though I’m a bit reluctant to pay £67 for a collet to be honest! 😬

 

[Hollowpoint]

On Hollowpoint Said:

Though I’m a bit reluctant to pay £67 for a collet to be honest! 😬

 

At that price – depending on how the collet holder attaches to the lathe – it would probably be cheaper to get a decent ER16 holder and a 6.5mm ER16 collet.

[not done it yetParticipant @notdoneityet]

Ream to size?

[ChrisLHParticipant @chrislh]

Don’t forget that it’s not just the collet but the collet holder and its attachment to the lathe that contribute to eccentricity.

[Michael GilliganParticipant @michaelgilligan61133]

It’s not obvious from the opening question, so  have to ask … would it be possible to do the job between centres instead of relying upon collet accuracy ?

MichaelG.

[Martin KyteParticipant @martinkyte99762]

If it’s in a lathe then either stick it in a four jaw and clock it true or a griptru 3 jaw and clock it.

Its also amazing how accurately you can do it with a home made split collet.

 

[old martParticipant @oldmart]

You are unlikely to get er40 collets in half millimeter increments, the clamping range exceeds that. You should try reclamping after turning the collet in the nut, it may find the sweet spot. I have plates for both er25 and er40 which fit on backplates in both lathes at the museum, and neither use a register. For precision work it would be posible to get things running spot on with patience.

[Tony Pratt 1Participant @tonypratt1]

I’ve just reduced the register on my 3 jaw chuck backplate and added 4 grub screws to the chuck body itself to make a ‘set tru’ setup, easy now to get within less than .01mm TIR. My ER collet lathe system is the same but without the screws.

Tony

[old mart]

On old mart Said:

You are unlikely to get er40 collets in half millimeter increments

In that case, please comment on the one shown in the post above. Is it a figment our our imagination? Is it fraudulent?

Link reproduced below for your convenience in case you did not see it previously:

Rego-Fix ER 40 Ø 6.5 mm Collet 1140.06500 (0645151)

 

[JasonBModerator @jasonb]

Without knowing the job it is hard to tell if a chuck will do, could be 6.5mm OD tube with a 0.2mm wall for all we know and chances of clocking that true in a 4 jaw and keeping it round in a 4 & 3 jaw are slim.

[HollowpointParticipant @hollowpoint]

I did consider clocking it in a 4 jaw, but it takes way too long since I am making a batch of parts.

I also have a griptru chuck but for the life of me I can’t seem to adjust it easily, and certainly not to within less than 0.01

For this particular job/s, collets offer the best accuracy/convenience balance.

[Tony Pratt 1Participant @tonypratt1]

You may have over tightened all 3 screws in the Griptru so locking it up. I would suggest making sure the chuck to backplate is just snugged up then undo all 3 screws and see where you are. From memory tightening one of the screws will push the work away from the screw position, you can basically get zero run out with a bit of practice.

Just Google ‘Adjusting a Griptru chuck’ and all will be revealed.

Tony

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, RDG Tools do a 6.5mm ER40 collet for les than a Tenner, don’t know how accurate they are, but I’ve got several ER32 ones from them, and they are very good.

Regards Nick.

[JasonBModerator @jasonb]

Nick I think you may be looking at 6-5 not 6.5

[Nicholas FarrParticipant @nicholasfarr14254]

Oops! 🥴, yes JasonB you are correct, thanks for pointing that out.

Regards Nick.

[PeteParticipant @pete41194]

Not enough information by the OP to know for sure if it would work for his needs. But if it’s multiple parts, then a fixture such as a Keats Angle plate might do it once it’s initial position was indicated in. http://www.homews.co.uk/page353.html

I don’t know about boring all ER collets, but I can pretty much guarantee my Bison ER 40’s aren’t going to be too kind to any carbide tip due to the interrupted cut and how hard they are. Grinding yes, boring to an accurate and parallel hole size, I have real doubts about.

[Author]

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