Decent ER40 - R8 Collet Chuck and Collets

Ray C

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All,

In another thread, I belly-ached about a poor quality ER32-R8 collet chuck https://www.hobby-machinist.com/threads/diagnosing-bad-er32-r8-collet-chuck.68829/ . At the same time that unit was ordered I purchased an ER40 chuck from a different vendor (see eBay link). This unit is running within acceptable norms. All the exterior dimensions fall within tolerance of both the R8 and ER40 specs. TIR as measured from the inside of the collet taper is within 1/2 thou (0.0005)". The surfaces are very good, ground and polished.

Given the state of quality control, I can only vouch for this particular unit. Given the very high quality finish and attention to detail of the one I received, whoever made this thing knew how to setup the machines.

https://www.ebay.com/itm/282743981503?_sp=p2488212.m41214.l9765&_trkparms=itemid:282743981503

As an aside, I also purchased a cheapo set of ER40 collets from a different dealer. I have spot checked about 5 of them using known good shafts and pin gages in my shop. So far, none of them have introdced any runout beyond what is inherent with respect to the chuck. I've checked at different lengths along the shafts and TIR is remaining within 1/2 thou. This means the collets are holding straight and seem to be running very true.

Same disclaimer as above, I can only vouch for this particular set of collets. Craftsmanship looks pretty good IMO.

https://www.ebay.com/itm/ER40-COLLET-12-PC-COMMON-SIZE-1-8-3-16-1-4-5-16-3-8-1-2-5-8-3-4-1-1-1-16-1-1-8/322043652757?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

I have no affiliation with these sellers.

Ray
 
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