Thread: Collets sizes and types plus and minus

Originally Posted by elanjacobs

As Chris said, they have a 1mm range (unlike 5C where you really do have to have both sets), so a 1/2" shank will go in a 13-12mm, 3/8" goes in 10-9mm and 1/4" goes in 7-6mm, you just have to tighten the nut a bit further before it clamps. Did it regularly on the CNC at my old job and never had holding issues. That's not to say don't get imperial sizes as well, you just don't have to.

If you would like to have a few imperials on hand consider getting MT collets instead of ERs. When I got my mill I already had ER32 metrics for my lathe so Anorak Bob gave me a few MT collets. 1/4, 3/8, 1/2" plus 6 and 12 mm. These are really handy because they are shorter and leave a bit more WWR (wiggle work room), especially on small mills and lathes

Originally Posted by BobL

When I got my mill I already had ER32 metrics for my lathe so Anorak Bob gave me a few MT collets. 1/4, 3/8, 1/2" plus 6 and 12 mm.

Lucky you. Is this what you are talking about? https://www.amazon.com/gp/product/B0...CBPE368U&psc=1

You can get them locally in MT2 and MT3. https://www.ausee.com.au/shop/category.aspx?catid=13

Originally Posted by jack620

Lucky you. Is this what you are talking about? https://www.amazon.com/gp/product/B0...CBPE368U&psc=1

Yes but they are of course MT4.
This smaller MNT3 subset are good value
https://www.amazon.com/dp/B01BH5Q7GM/ref=dp_cerb_1

You can get them locally in MT2 and MT3. https://www.ausee.com.au/shop/category.aspx?catid=13

Unfortunately it doesn't look like Ausee has them in imperials.

This 11 piece set of imperials from CTC look like good value - shame about the freight costs.
MORSE TAPER #3 IMPERIAL COLLET SET (11 PCS) #F78 | CTC Tools

I bought an ER25 set which, I think, top out at 16mm. My lathe has a 25mm bore, a MT2 tailstock taper and 280 swing. I went for the ER25 because I use drills in them rather than work. It takes a fair amount of tightening to do the collet chuck up, so much so I added to the length of the chuck spanner. My lathe's drill chuck takes up to 16mm after that it's step down drills, hence the ER25 collets. Mine were sourced on ebay, the cheapest I could find. Excellent quality and I never had any problem with burrs.

Originally Posted by 4me

It takes a fair amount of tightening to do the collet chuck up, so much so I added to the length of the chuck spanner.

A ball bearing nut might help with that if you don't already have one. It shouldn't be difficult to tighten them.

https://www.ausee.com.au/shop/item.aspx?itemid=1304

+1 for ball bearing nuts.

If you want to stick with plain nuts, a drop of air tool or light machine oil on the tapered surface that presses against the collet (as well as a drop or 2 on the thread) can help keep things rotating more freely.