QMT High Precision Adjustable ER-40 ER Collet Chucks and 5C chucks in D1-4 and D1-5

mksj

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Looks like QMT/Precision Mathews is now stocking high quality adjustable (set-true style) ER-40 and 5C chucks with either D1-4 or D1-5 back plates. I have seen the 5C version (also posted a picture he sent me) and it is very nicely machined, either is a nice addition if you use collet chucks and want a higher quality chuck that won't bust the piggy bank.

QMT 5C Set-True chuck.jpg
 
I have always been intrigued by the ER collets over the 5c. Can anyone shed light on the pros and cons of ER vs 5c. I believe that the ER series has more of a gripping range than the 5C?
I am really tempted to pull the trigger on that D1-4 ER.
 
I have always been intrigued by the ER collets over the 5c. Can anyone shed light on the pros and cons of ER vs 5c. I believe that the ER series has more of a gripping range than the 5C?
I am really tempted to pull the trigger on that D1-4 ER.

I have the one from shars and use it about 70% of the time, the other 30% split between my 3 and 4 jaw QMT. I would not be without one, but that's just me.
 
I added the ER and a full set of metric collets to my 1340GT lathe order. For the price it’s a no brainer (to what’s left of mine).
 
@7milesup I believe the big difference is the gripping area. On a 5C you can get away with just gripping on the end. That's a big no no with an ER.
Also the small clamping range. The advantage is you don't have that big nut in the front like the ER. ER's are supposed to slightly more accurate as well.
 
Two camps on ER vs 5C collets for lathe material holding. Having both, I primarily use 5C for a couple of different reasons. I not a fan of having to have a wrench and a nut to tighten the work, 5C can handle much shorter stock which is what I am most frequently clamping. I use a speed handle on the 5C chuck so very quick to change collets. Downside of 5C, limited holding power vs. ER collets for longer stock, limited clamping range, really requires a 1/64th" increment 5C collet set. ER collets tend to clamp uniformly from both ends so less axial run-out the further you go from the chuck. ER collets tend to have a smaller TIR, but it all depends on the quality and the clamping range.

If you look at something like an ER-40 collet set, many vendors will sell you a 1 mm increment set and say it covers the full range. Personal experience is although they may be advertised as 1 mm clamping range, the TIR sucks at the extreme range. I use a 1/32" increment ER-40 collet set and my high accuracy ER collets are not made for a range of clamping, but a specific increment. In addition with ER systems, a higher quality clamping nut and better collets (like techniks) make a significant improvement in TIR and axial skew of the work.

Since both of the chucks noted above are set-true (adjustable for run-out) you can compensate for slight variations in collet TIR if needed. So a matter of preference, but nice to see that there are two quality options with regard to adjustable collet chucks that are reasonable priced. This fills a big gap in the market for these chucks between the really poorly made cheap lathe collet chucks and the expensive high end ones.
 
@mksj, thanks for a good comparison. I was ready to pull the trigger on a Shars ER-40 collet chuck with a D1-6 backplate last week. Unfortunately either the collet chuck itself or the backplate was on backorder, not sure which one.
 
If you're going the ER40 collet chuck route, I highly recommend replacing the OEM collet nut with a high quality version from Rego-Fix. I've tried ER40 nuts from about 7 different brands in an attempt to improve TIR and collet removal when loosening, and nothing beats this one with ball bearing for ease of tightening/loosening:

 
I need an economy 5C collet chuck for my PM-1030V. This lathe has a proprietary backing plate.


PM sells the backing plates for about $70. I wonder if they have a (universal mount?) 5C collet chuck for that.

Edit: it looks like they do not have a universal mount:

 
Based on my research (not experience), Mark‘s comparison sums up the differences succinctly.

An old saying is “horses for courses”, and this is just another good example of that truism.

In the end it seems to me that a complete tooling setup would eventually include both ER and 5C, and someday I hope add a 5C setup. For now however, trying to justify a $320 addition to my order is easier than a $680 addition. It’s always that darn money thing!
 
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