ER Collet choices

[not done it yetParticipant @notdoneityet]

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.

[Bill PudneyParticipant @billpudney37759]

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

cheers

Bill

[old martParticipant @oldmart]

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

[Turbine GuyParticipant @turbineguy]

Posted by David Caunt on 04/03/2021 19:05:26:

Now realise that yes I can use all the collets but the length is limited so if you are thinking like me then buy an ER25 mounting for a faceplate for the lathe. Then you can take up to whatever your lathe mandrel will take.

 

Dave

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

[Howard LewisParticipant @howardlewis46836]

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

[Author]

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