Hi Chris i have ER25 collet chuck MT2 taper which i use on the Mill. I would not be without them. I also have a Clarkson autolock chuck.

Maybe the Clarkson is more accurate. The ER collets are a great addition to the lathe or mill. You will not go far wrong buying a set. I believe they do Imperial & metric. Mine are metric, but do hold some imperial tooling & drill bits.

Steve.

I have a set of ER16 collets for my Taig Lathe and ER32 for my Mill. I would not be without them.

Metric ER collets will squeeze down onto Imperial sizes so there’s no need for two sets.

I was able to buy secondhand collets for the mill from an EBay seller at a good price – so it pays to keep one’s eyes open. The Mill was supplied with an R8 collet Chuck.

But after a couple of days I invested in the Ball Bearing nut!

Good luck

As I see it, the main advantage of dedicated sized collets is the extra head space afforded on the mill.

One set of ER collets will cover the complete range – but accuracy is only guaranteed (if it is) at the nominal size if that is important.

I mostly use ER collets.

I seldom use finger collets though they do come in handy on the odd occasion when a bit more head room is needed. On the lathe I have 5C and on the manual mill ER32 is the norm, ER16 on the CNC.

You also have the conflict of wanting something for work holding on the lathe where a larger max diameter is desirable and cutter holding on your small mill where access to the work needs to be considered. You may well find that with small cutters on the mill held in finger collets that the spindle makes it hard to see what you are doing and can get in the way when working near clamps or a vertical rotary table so something like an ER16 set or Weldon type holders would be better than finger collets or a big ER32 chuck.

I find ER collets super useful for holding parts accurately on my mini-lathe. They are especially useful when a part is removed from the chuck to have other work performed on it before returning it to the chuck and being able to maintain concentricity. Or, as others have mentioned, if the part is to be turned round e.g. when you want to machine both ends of an axle.

Because collets grip a part more securely than a 3-jaw scroll chuck it will not spin in the chuck when doing things like using taps and dies. (Been there, done that, said some rude words…)

The thing with ER collets is they are designed to very accurately hold a part that is at least as long as the collet. So what do you do if what you are trying to hold is shorter than the collet? The best solution I have found, so far, is to first insert a bar of exactly the same diameter as what you are trying to grip. It doesn't need to be the same material as the part (just the same diameter), aluminium or even delrin/acetal will do.

Chris' question was specifically about getting MT3 collets, not ER. As someone above said, the great advantage if that you gain perhaps 50 mm more daylight under the mill head, as well as greater rigidity. Single collets are quite cheap and you only need a few for the main cutter shank sizes.

Not much benefit in MT collets if you're like me! They save headroom on a mill compared with holder-mounted systems like ER32, and may be a little more rigid, but I can't think of any other advantages.

More complicated on the lathe. Most of what I do is held in a 3-jaw chuck, which is quick and convenient. 4-jaw comes out when reset accuracy is important, as when a job needs work to be moved between machines. 4 jaw chucks are wonderful except setting them up takes time. Lathe collets beat 4-jaws when quick accurate resetting of round objects is frequently required, as in clockmaking. Not called for much in my workshop.

However, once in a blue-moon I make something that moves repeatedly between machines and collets provide the best answer. They allow the job to be accurately repositioned several times without fuss. All done with an ER Collet Chuck on the lathe, supplemented with Stevenson Blocks on the mill, and although the approach is good enough for my needs, someone doing a lot of this sort of work might go up-market.

I suspect if Chris hasn't hit a requirement for MT collets, then he doesn't need them. Yet! In the middle of a job one afternoon, I suddenly realised an ER collet chuck on my lathe would have saved a huge amount of time and a couple of rejects. That's when I ordered a collet chuck. Likewise, I bought a couple of MT collets for a particular job, but in the event they weren't needed – waste of money.

Dave

Another throwback "must have" from industry. Must be one of the most abused items in the toy Ingineering hobby. "I can fit imperial items in my metric collets" ( or vicky verky ) and "it grips 15 – 14mm" Garbage, no, 15mm grips a 15mm shaft and NOT smaller or 9/16". What's difficult to understand that a bore of a specific diameter magically reduces? Bit like expecting an M6 die will cut M5 if you crush it down a bit. Extreme but you get the idea. If you're going to make dozens of studs of a specific diameter on a regular basis, fine buy a specific size collet, otherwise 3 or 4 jaw is ideal.

A few decades ago, school had two lathes in the Metalwork class. Big one was a Harrison (they were a couple of miles down the road at Cleckhuddersfax), and a Boxford (they also were not far away) Boxford had three collets, can't remember what the two bore sizes were but third was 1/2" square cos everyone made a centre punch from 1/2" square bar.

As previously mentioned, an Autolock clone and 6mm and 1/4" (one each) for Weldon cutters.

Regards Ian.

Edited By Circlip on 16/10/2020 11:10:36

Forgot to mention, ONLY collet for multi size gripping is the "Rubberflex" type.

Regards Ian.

I have the complete set of metric MT3 finger collets because they fit both lathe and milling machine. As someone has said, although on the milling machine they do give an increased headroom, there is the downside that I cannot reach far enough down and as I haven't got a milling adaptor I struggle.

On the lathe, I have found that using these collets reduces/eliminates the chatter I used to experience when trying to mill in the lathe, so an advantage there. I assume this is because the cutter is so much nearer the headstock bearings.

Another problem is that they do not hold imperial sizes. No matter, in general I turn down using one of the chucks then transfer to a collet.

Peter G. Shaw

I purchased a set of ER16 collets in Imperial Fractional sizes for my lathe.

I was VERY surprised to find that three of the set were actually labelled in metric sizes even though I had ordered Imperial.

The collet in the box labelled 5/32 is actually marked 4-3
The collet in the box labelled 7/32 is actually marked 6-5
The collet in the box labelled 9/32 is actually marked 7.5
The collet in the box labelled 5/16 is actually marked 8-7

I complained to the seller and almost 20 messages went back and forth – but I might as well have banged my head on a brick wall for all the good it did!

I resolved to stop buying things from China if I wanted any sort of Customer Service!

MC