ER32 which end mills

Martin is right. There are some which don't have flats on the main body - perfectly normal. In such cases, spindle lock/find some way to hold spindle/spindle drawbar/peg type spanner with location pins (usually supplied with machine specifically for this purpose) to hold certain spindles at the bottom/ or grind flats on body as suggested.

Ketan at ARC.

Edited By Ketan Swali on 18/03/2018 13:09:54

And just to illustrate Ketan's point, one with and one without plus a couple of his nuts!

Don’t make a lot of difference. I still cannot tighten down some of my collets, by hand, to grip the minimum size for that collet.

No problem with first half a mm, but not for 0.9mm ( for example) under the nominal maximum size of the collet. You might be able to, but I can’t. So fitting a nut to hold some threaded end mills in the collet while tightening with two spanners, requiring both hands to be used, seems to me to be a good tip if changing tools repeatedly.

Treat yourself to some imperial collets

Jim

Edited By jimmy b on 18/03/2018 13:46:31

Or a ball bearing nut may help you close up by hand on smaller stock. It also lets you get a better grip when finish tightening with a spanner. They are a good example of a modest upgrade whose benefit far exceeds the cost!

Neil

Good point Jim - like NDIY, I prefer not to really tighten over the halfway point of the given ER 'range' - which means that some Imperial cutters can be handled OK (in Metric collets) but others less so, particularly smaller items ...

So 3/8ths & 5/8ths (at 4.76mm/7.94mm) should be OK but 1/8th & 1/4" less so (at 3.17mm/6.35mm) in my view. So whilst I don't have a full set of imperial ER collets, I do have those that would be close to the full closing range of the metric one.. I always use low friction nuts on anything over 'halfway' but I am still not fond of doing so.....

Regards,

IanT

Ian,

I don’t mind at all - I use the full 1mm range. It is just tightening the collet to get a grip on the shank sufficiently, to then tighten it fully with both hands on spanners. No problem with x.9mm but x.1mm can be a pain if I need to make umpteen repetitive changes of tool. As simple as that.

As for JB saying that a 0.9mm smaller shank (than the nominal max size of an ER collet) will hold in place - well I don’t believe him, unless he has it horizontal, not vertical.

Do note that my initial reply was to Tim’s post (that was why I ‘quoted’ his post). I would not dream of using a shank different than the nominal value of a Clarkson collet!

I said cutters, I did not say 0.9mm smaller than the largest range size.Cutters come in standard shank sizes eg 1/4", 3/8", 1/2", 6mm, 8mm, 10mm, 12mm, 16mm, etc and I have collets in all those sizes as the largest size of their range.

What cutters do you have with odd size shanks?

Mine stay in the collets be they metric

Or Imperial

Edited By JasonB on 18/03/2018 18:51:37