View Full Version : ER Collet Advice

08-25-2016, 03:00 PM
Just received a set of ER 32 collets and a MT 4 / ER 32 collet chuck for my lathe. I have never used these before and wanted to know the do's and dont's of using them. any and all advice and suggestions are welcome.
Thanks, steve

08-25-2016, 03:08 PM
First thing is to tuck the collet into the nut before putting the collet/nut into the chuck. Never put the collet in the chuck and then try to put the nut on.


08-25-2016, 03:13 PM
Don't try to force something larger than the size marked on the collet, into the collet. ER collets have a large grip range, but they only go smaller, not bigger.

08-25-2016, 03:13 PM
Thank You Pete,


08-25-2016, 03:25 PM
This page explains it with pictures http://www.precisebits.com/tutorials/er_collet_system.asp

Further to what Toolguy said, I don't think you are meant to go below the minimum size either. They have a 1 mm range, and you should stick to that to avoid damaging the collet.

Does your collet chuck have a drawbar, or is it only held in by the taper?

08-25-2016, 04:00 PM
Keep your collets, threads and tapers clean and lightly oiled, a dry lube is even better, I use Tungsten Disulphide.
Bearing ER collet nuts are worth a punt, the increased tightening force for reduced torque is nice.
If you're doing a repetitive job with several sizes of collet required, multiple collet nuts make this a more pleasant process.

- Nick

08-26-2016, 01:35 AM
MT4 will mean a drawbar and no long jobs thru the spindle. Personally, i would have bought a backplate mount type ER 32 chuck, and either bought a backplate or made one if not available commercially at a reasonable price. That way you can throw long jobs all the way thru the spindle.
Also ER 32 only goes up to 20mm collet size i believe. With MT4, would it not have been better to go the bigger ER 40?
My 2 Bahts worth...

08-26-2016, 02:20 AM
Thanks fellas for answers and advice. Yes am building a drawbar to secure the chuck, Interesting aside / the small end of the mt 4 was a bit larger than the pass thru diameter of my spindle so had to true and center drill a 1/2 " shaft then into the 1/2 " collet and set the chuck up between centers to turn the end so it would clear the spindle. Nice material on the chuck it turned down really nice.
Got this set thru CTC tools , ordered on 8/10 and delivered today. from Hong Kong to Denmark to Oregon. The quality looks great, nice finish and price was very good. Not a clue to how they make and sell them for such low bucks.

08-26-2016, 02:45 AM
Yes thaiguzzi I gave quite a bit of thought to what you said regarding the backplate mount. On pass thru stuff I just use my 3 or 4 jaw chuck with a spider I built for outboard support. This collet set will be for short bits and pieces for the cannons I build and small engines I hope to build in the days to come. Yes, have had to build 1 backplate for my 4 jaw chuck and then tackled a faceplate I wanted fabbed from a 10 lb cast iron weight and a hydraulic cylinder spacer sleeve set into the weight and then brazed. Turned out very well. Just finished modifying and rebuilding an old South Bend milling attachment to fit on my cross slide , its very rigid and milling with it for the small jobs I do in my home shop has gone very well. As with so many others on this forum we, wife and I are retired and get by ok with small needs and income.
She, wife # 1.refers to my lathe as my "other wife" but seems ok with sharing me :D . When I get this picture thing thru a hosting service figured out I will put up some pics of shop, projects and such.
Thanks for all the help, steve

08-26-2016, 04:24 AM
... With MT4, would it not have been better to go the bigger ER 40? ...

That's rather like the old joke which ends with "if I were you, Sir, I wouldn't start from here".


08-26-2016, 09:21 AM

A couple of things:

1) Make sure you tighten the nut enough. The torque requirement is fairly high.

2) If the part going in the collet is very short, you may run into a situation where the mouth opens up and you are holding the part just by the very back. In that case, just make a short plug of the same diameter and insert it in the back of the collet so that the net effect is that the collet is gripping on a uniform sized item.

Lastly, make sure you check out Arceurotrade (http://www.arceurotrade.co.uk/catalogue/results.aspx?search=Collet+block), they have a number of accessories to use with ER collets. I just got the collet blocks for ER32 and ER40.

Also, for others that have a 5C collet ready lathe, this adaptor (http://www.arceurotrade.co.uk/Catalogue/Collets/5C-Fixtures/5C-to-ER32-Collet-Adaptor-2) will get you into the "no-gap" world of ER collets for a very modest price.

I got this last item myself only to use on my 5C spindex. But some times, I just throw this in my 12x36 lathe spindle with a 5C collet closer for a quick job where I just don't want to go through the hassle of mounting another chuck.

Have fun with it.


08-26-2016, 09:29 AM
Shoulda got ER40.
Why limit yourself?