If used on the lathe they can be very handy for holding thin or delicate items that may be damaged by a 4 jaw chuck for example think how you would adjust a bit of thin wall tube in the 4 jaw without distorting it or faffing about with packing to save marking the surface with the jaws

Boring 3/8" eccentric hole 2" long which left 0.010" wall on the thin side

I have started this new thread to answer Colin's question about ER blocks hence no opening post by him, just the quoted part.

Edited By JasonB on 24/10/2017 13:26:27

Blocks like this for 5C collets have been around for a long time and I've got some home made ones for 2MT collets I made ten years ago. I was using them mostly for grinding and sharpening various tooling.

Edited By JasonB on 24/10/2017 13:23:34

I have both square and hexagonal ER25 blocks which I use mostly on the milling machine. BTW, are these attributable to the late JS?

Rik

Colin,you are right and no problem about the thread.

Though do be careful if working on the end of a long bar that the block is seated down well as the bar can cause the block to tilt and you get an irregular 4 or 6 sided shape. I find the Stevenson spin indexer quicker than the blocks.

Rik, both designed by the late JS along with metric 10-20-40 and 20-40-80 blocks also available via ARC.

PS – looking more closely – that is my 5C block and I only had a few sizes of 5C collet back then, so the 1/8th rod was held in a brass adaptor – but these days it would be held directly in an ER collet….

IanT

I find the blocks very useful. Quick to put a square or hex on a round bar and a simple way to hold a piece of round bar very securely without bruising the surface. Secure the bar in the block and then put the block in the vice or clamp to milling table.

Yes indeed Michael,

Another use that comes to mind is when tapping into the end of a rod. Whilst tapping can be started in the lathe (which is good for getting them in straight) – if the work is held in a 3-Jaw – then sometimes the grip can be limited and the work will turn in the chuck instead of being tapped. Assuming any 'turning' work is finished, then taking the work piece out and griping it in a collet & block (held in the vice) will usually allow the tapping to proceed.

It's much better than just trying to grip the work in a vice alone….

Regards,

IanT

Very useful for milling at an angle:

+1 for Ian T's comment. Very good at getting a good grip on circular stuff in the vice – will hold a 1/2" bar for screwing BSW with a die without turning the job.

Rod

Yes sorry Neil, I didn't mean to confuse anyone.

To a large extent my tools reflect the commercial availability of "stuff" over the years – which I think we've discussed before. So folk like myself who been going a while have probably 'evolved' their tooling over time.

My first collet blocks were 5C ones (all you could get back then) and I just purchased a few 5C collets to use with them. Then (I think) came a 5C Spin Indexer, to which I later added a 'Stevenson' ER32 adaptor – which resulted in my selling my 'Chinese' MT2 collet set – and purchasing a full set of ER32 collets. This was fairly rapidly followed by several ER32 collet chucks (for both lathes).

When Arc brought out their 'JS' ER32 collet blocks – they were an obvious thing to add to my ER32 collection. So I've still got both the 5C & ER32 collet blocks and it's sometimes useful to have them all (in truth I don't really like selling stuff either – nasty case of tool hoarding I'm afraid)..

However, if starting over now – I'd just buy the ER blocks (ER32 in my case but others prefer ER25)…

BTW – I also use ER16 collets/spindles for some work – and would probably buy ER16 blocks if they were available – although I could probably make some simple 'block' style accessories given that I've got the spindles….

Regards,

IanT

I have had success holding short lengths in ER collets by putting a short slug of same sized material in the other end of the collet.