Boxford / Myford ER32 collet chuck from Chronos

Biggest problem I see with these types of chuck is that they have been machined up, hardened and ground to suit the thread and register common to the lathe they are destined for.

This assumes that your thread and register is also accurate on a worn machine. If for some reason it doesn't fit the register snugly then it will throw the ER collet bit off and unlike a backplate that you skim for accuracy on the host lathe you are stuck.

Technically they should be perfect but if it does run off who do you blame, chuck or spindle ?

There are at least two people out there selling backplate mounted ER collet chucks that can be fitted to any lathe for that matter and even swapped between machines if the need arises.

In terms of function and cost this two part method, backplate and chuck works out better.

-- Regards,

John Stevenson Nottingham, England.

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Also works out well if you ever move to a new machine. I went this route with the Warco backplate mounted ER25; they also do ER32 although it looks like Arc's are cheaper (see below).

Arc do ER32 backplate mounting chucks, and I've just noticed that they also do ER25 in two sizes of backplate mount - the smaller of which looks a nice match for my Taig lathe...

Regards, Tony

Boo,

One or two of us got the Chronos ER25 collet chuck for the Myford nose and got a bit of run out - in my case the run out was about one thou which I put down to a slightly loose fit on the register of the spindle. I got my spindle and register checked out and it was spot on.

If you dig back in the archives of this group almost two years ago, you'll find a longish thread on the matter.

I eventually bought a faceplate holder from Warco and a threaded backplate from Myford and have now got a holder with a runout of about two tenths, and I could probably get it better than that. As a matter of interest the overhang on the backplate version and the nose fitting version is about the same.

Jim.

Boo

Hi, my vote goes the same way as John, Tony and Jim. I have both types of chuck for my ER 32 collets which are Vertex bought from Chronos and they are superb. The screw on type od chuck for my Myford and Boxford and the backplate type for the larger Warco. I made the two smaller ones form an article published in EIM and they are both accurate and repeatable to a few tenths. As Jim says the backplate version can be made extremely accurate but of course is only as repeatable as the backplate/spindle mount will allow. I bought the Arc Euro ER32 version and a Warco backplate and it currently repeats within .0002" on fitting to the spindle. The backplate register is turned on the actual machine you are using so the assembly should be accurate. I found the Arc ER32 version very good. I also have a selection of ER 32 Collets from other suppliers (Arc, J&L and Warco) they all seem equally good and are within the supplied spec for concentricity for economy collets (.0002"). My Boxford chuch is unhardened and when it shows signs of wear I will not bother to remake but buy another backplate version for that lathe without any concern whatsoever. As has been said if I change the lathe then all I have to get is a suitable backplate and I'm up and running again.

Best regards

Keith

Thanks for all the replies, the hoped for effect of a surge of emails to Chrosos expressing interest in an ER32 version of their chuck seems a bit unlikely to occur. However by a serendipitous coincidence the latest issue (122) of MEW promises that there'll be a description of just such a device in the next issue, so maybe I'll build that instead.

Cheers,

Boo, if you e-mail me a valid address I will send you a PDF copy of the EIM version of an ER32 chuck for the Myford if it is of any use for you. It is very simple to convert for the Boxford by just increasing the length slightly and changing the spindle register/ thread. Mine works fine on the Boxford and was very straight forward to make.

regards

Keith

Hi Keith,

That's a very kind offer - please could you send it to boo it clockwork dot freeserve dot co dot uk.

Many thanks,

I didn't see anyone mention it yet, but a well-known supplier in Hebdon Bridge appears to stock these. YMMV.

Just waiting while the next batch comes in....

Steve

My mileage generally stretches to a longish detour around that particular supplier :-)

The spindle collet set-up by Myford isn't that badly priced if you only want to hold a couple of sizes, the holder and setting tool are pretty cheap, the collets are what costs. They hold the collet in the MT2 spindle which should help the accuracy?

Stu G