Myford Super 7 and ER40 collet chuck

I am looking to purchase an ER chuck, set of collets and backplate from ArcEuro for use on my Myford Super 7. However, as neither Myford nor RDG offer anything above ER32 specifically for the Super 7 I wondered whether the ER40 is deemed too unwieldy. Does anyone have any views on this?

Specifically, I am wondering whether the benefit of being able to hold, say, 1" material accurately in the ER40 chuck, as opposed to the more limited (3/4" capacity of the ER32 chuck, would outweigh the drawback of the additional chuck size (and of course the higher cost) of an ER40 system. I realise that stock at these diameters would not be able to pass into the lathe spindle's bore.

The only ER system I currently own is an ER20 MT chuck that I originally purchased for my woodworking lathe.

Many thanks,

Mike

The "old" Myford did do an ER40 chuck to fit the big bore lathe, I have one. You could make one, it's quite easy to machine both the internal ER taper and the closer thread, and you'd have good accuracy if you had a well-fitting blank to fit the nose thread to start with. You can buy ready-made closer nuts fairly cheaply, even ball bearing types.

But the length limitation I suspect would be a PITA, you'd have hardly any length behind the collet.

I have an er40 chuck for my Boxford which isn't really any bigger than a myford so I don't think it would be too big. In fact the collet chuck is probably smaller and lighter than a bog standard 3 jaw. I stumped up the extra for the er40 for the same reasons of extra capacity. I think it's worth it, 1 inch is a very common size used in our hobby, I'm almost certain I would have regretted it had I gone for the Er32 size.

Thanks for the advice. ER40 chuck ordered today.

Many thanks,

Mike

Too late for Mike, but just in case anyone else is interested - Gloster Tooling now do a range of larger ER32 collets which extend the 20 mill max (of ER320) up to 1 inch. That said, they are very expensive (around £20 each), so the extended range alone would cost as much as a complete set of the sizes up to 20mm. Might help get someone out of a hole and as Mike initially observed, being able to hold 1 inch material is quite handy.

Regards Tom

I went with ER40 because it gives me up to 32mm with extended range collets :D

You can always make your own collets and make special step collets from 4140 or 4340 as it comes already pre hardened but still very workable with HSS tooling etc

Neil