ER Collet choices

Thanks once again for all the detailed answers. If I’m reading correctly then the general opinion seams to air towards ER32 so may start off with this. Not the end of the world to buy ER 25 in the future.

clay

I have a WM16 mill ( 2012 ) & use a ER25 collet set in it. I also have a MT4 collet holder for the headstock of my WM250 V-F lathe, I have both Stevenson square & hex collet blocks, I'm one of those 'nice to have it 'guys; & have the hex block semi permanently mounted in my 3 jaw chuck, does all I need it to.

George.

If I’m reading correctly then the general opinion seams to air towards ER32

TBH, I only saw one isolated posting which actually recommended ER32 to the exclusion of ER25., so I think you need to read the thread again, quite/more carefully. You need to choose dependent on machine(s), type of work anticipated, etc. Following what you think is ‘the crowd’ is likely to lead to disappointment or extra cost. I, for one, did not make any recommendation as the final choice is yours - and yours to take responsibility for.

The one thing I would not be doing would be to buy two adjacent sizes of collet chuck. Hence my choice of ER16 as my second set to adequately ‘fill the gap’. When I chose ER32, I considered ER40, but reckoned that I would need a smaller set at some time and ER32 was big enough - what with collets outside of the normal range being available, if needed. My second set could easily have been ER20, but I chose ER16 as suiting my needs.

I note that 20mm collets were available (6 years ago) for ER25.

Edited By not done it yet on 05/03/2021 19:01:06

NDIY, maybe you were in such a hurry you obviously missed my ...." although there are larger ones ". These larger ones are only available from a few suppliers. My point was that the largest normally available collet is nominally 20mm diameter.

I don't consider anything wrong with my Clarkson Autolock. My preference is for the ER32. If your preference is for the Autolock then clearly that's your choice and good for you.

cheers

Bill

Sorry, missed the bit about larger ones. ‘Nominal’ wrt ER collets, to me, means exactly that - it will accept a shaft of that size with the maximum run-out specified (but will compress by a certain amount to accommodate a slightly smaller diameter, but not with the eccentricity specified for that ‘nominal’ value). Perhaps a little confusing as I would expect the biggest to mean the largest.

On the second point, you were clear in your assessment and I was clear with mine (with the reasons for my concerns being explicit). Salient points for the ER system being advantageous. I could have added a couple of advantages of the Clarkson but chose not to.

For clarity one advantage might be a more securely held cutter (but I have never experienced a cutter moving within the collet - perhaps because I tighten my ER collets to a rather higher degree than many). Another might be the relative ease/speed of changing collets - what with the ER system requiring a much higher torque and my collets generally being already fitted with the cutter.

Yet another advantage of the ER collet system is that they can accommodate a small range of sizes below that ‘nominal’ size, thus allowing the use of some metric collets to hold slightly smaller standard size imperial cutters.

Please note that I used the word ’may’ which is not definitive. I have both. I use both. But I do prefer the ER. I mentioned that I had a different type of collet holder but did not suggest there was anything that stopped me using it. I consider that most tools are a compromise - there are very few ideal situations within the hobby.

The OP has more than sufficient points to consider - and remember he is only wishing to initially buy a single set of ER collets.

Excellent, so basically we are all on the same book if not the same page!!

cheers

Bill

I bought a set of the cheap collets and found two things. Firstly, they were not very good, and secondy, there are many sizes that never get used on a mill. Now I use 3,4,5,6,8,10,12 and 16 er25 collets bought separately from APT, and also the Vertex brand. I would be unhappy if the runout was over 0.025mm, (0.001" tir.

The multiple editing has failed to get a righthand bracket to stay when I "save changes". So the wink is here to stay.

Edited By old mart on 06/03/2021 15:35:54

Edited By old mart on 06/03/2021 15:36:13

Edited By old mart on 06/03/2021 15:36:52

Edited By old mart on 06/03/2021 15:39:33

I agree with Dave. If you can get a collet chuck that will let you pass the unused length through the bore it is a big advantage. I have a Unimat 3 lathe, so space is very important. The EMCO ER-25 collet holder allows be to do this. The following photo shows how much my reamer would stick out if the depth of the collet chuck was very short. Being able to pass the shaft through allows the amount of cantilever to shortened considerably.  I should point out that the lathe is running in this picture that was taken to show how little the run-out is with EMCO collet chuck.

Byron

Edited By Turbine Guy on 06/03/2021 18:01:50

Old Mart,

I avoid the ****** smiley by leaving a space before the closing bracket , if it is any help!

Having an ER Collet chuck on a morse Taper limits the length of material to little more than the length of the collet, before it hits the arbor.

Having an ER collet chuck on a backplate allows work to maximum ID of the Mandrel to be passed through.

I tend to use the Backplate type for workholding on the lathe, and the arbor type on the mill, for holding cutters.

Howard