I've only ever heard of them for 5C. I kept suggesting to the late John Stevenson that he make some for 3C since there are so many of those collets around for Boxfords. 6, 8, 10mm sizes would also be logical developments of the theme.

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That's very similar to the one I mentioned … useful, but not what you are looking for.

You presumably want something more like the ones I pictured on this thread from 2017:

**LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=131257&p=2

MichaelG.

The one thing I'm always wary of with the 5C blocks is that when you use them vertically they are stood on the end of the collet as it and the nut stick out the end, not a problem with ER blocks.

I wonder if this could be avoided if the block were made a little longer and a recess cut for a "nut" that could be tightened with a two pinned spanner so nothing stuck out the back. Possibly make a second larger flanged nut too for when you want that to act as a stop as discussed previously in Michael's linked thread.

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[my emboldening]

Jason: If you scroll down Phil's recently linked page: **LINK**

http://www.wefalck.eu/mm/tools/attachments/attachments.html

… to 'Upright Collet Holder'

You will see that's exactly what was done [albeit on a much smaller scale than 5C]

MichaelG.

Be careful here. Pultra 10mm collets are not the same as Pultra10 collets, which are probably 8mm collets.

Phil P — thanks for posting your excellent and very clear drawings.

I am thinking of making a pair of these collet blocks, and maybe a third one in a cylindrical form. Can I ask – did you make them, and did you make any changes that were advantageous?

I was thinking of using Jason's idea of making recessed nuts, for instance.

Thanks

Colin