What Collet Chuck have I got?

**Robin Hewitt** · 17-11-2008

Originally Posted by irving2008

Yes, there's something that looks like a little centre in there.., here are some pics...

That's the one...

Screw the nose shut, it doesn't grip until the cutter is in place. Screw in a milling cutter until it hits the pin, open the nose slightly so you can screw the cutter in another quarter turn then tighten the nose.

Don't screw the cutter in too far, smaller sizes can shatter if not supported by the threads because the nut drives against them.

**irving2008** · 17-11-2008

Originally Posted by Robin Hewitt

That's the one...

Screw the nose shut, it doesn't grip until the cutter is in place. Screw in a milling cutter until it hits the pin, open the nose slightly so you can screw the cutter in another quarter turn then tighten the nose.

Don't screw the cutter in too far, smaller sizes can shatter if not supported by the threads because the nut drives against them.

Hmmm, I dont understand - what does the cutter 'screw' onto, there's no thread as such inside...

[edit]Ah - I see... its a Clarkson Posilock.. uses threaded tanged collets... so I need to buy a set of collets at £35 then some special threaded endmills at £5 - 8 a go...

Should I maybe just go get an ER25 or ER32 collet set...?[/edit]

**Robin Hewitt** · 17-11-2008

Originally Posted by irving2008

Ah - I see... its a Clarkson Posilock.. uses threaded tanged collets...

So you didn't get the wooden box with chuck, spanner and set of four Imperial collets then?

No great loss, compared to the ER32 I now use, it's a piece of dung. Millling cutters from yesteryear only.

I tried inserting a bolt in the back of the 1/4" collet to give it something to press against so I could use an unthreaded cutter, but it didn't have the grip.

**irving2008** · 17-11-2008

Originally Posted by Robin Hewitt

So you didn't get the wooden box with chuck, spanner and set of four Imperial collets then?

No great loss, compared to the ER32 I now use, it's a piece of dung. Millling cutters from yesteryear only.

I tried inserting a bolt in the back of the 1/4" collet to give it something to press against so I could use an unthreaded cutter, but it didn't have the grip.

Thats all the argument I need to go buy an ER32 chuck with collet set from RDG or Chronos...

**irving2008** · 17-11-2008

Thinking this through further... my lathe has an MT3 taper also would it make more sense to buy:

ER32 MT3 Collet set

or

MT3 Collet set

Whats the advantage/disadvantage of the direct acting collets?

**Robin Hewitt** · 17-11-2008

MT3 collets will reduce the overhang but I don't think they are so keen on intermediate sizes like ER32 which has a much steeper taper and slots from either end. Could be wrong, usually am.

If you go ER32, I prefer the spanner with lots of teeth rather than just one. Can't slip off. Alternatively a long spanner for the top so you can brace it against the column. Just avoid heaving on two spanners at the same time if one of them isn't 100% secure, saves unexpected leaps backwards or heads colliding with milling machines depending on which way you are turning it.

When I started using ER32 I didn't realise you were supposed to hook the collet in to the nose before you put it on the chuck. Nice feature because they eject. Had to break one to find out.

If you buy ER32 check the run out as soon as it arrives. Run out is part of ER32 spec so if yours exceeds the stated tolerance you can send it back, not as advertised.

Nice to have the whole set, but most of my set are still virgin and untouched. The 7-8mm has lost it's shine along with a few of the smaller sizes. I find CNC usually requires a smaller diameter cutter because my software won't adjust the internal radii to rough out with anything big. I keep a 3/4" reduced shank cutter in that Clarkson for top facing.

**irving2008** · 17-11-2008

I could see that MT3 collets would enhance rigidity a little and would allow different length tools to be evened up to reduce the number of times it would be necessary to move the head up and down.

TBH apart from drilling its unlikely I would use a vast range of collets, more than likely could support most milling operations with a limited set of endmills and a facemill/flycutter on the MT3 taper

Will think on it some more...