I may have the opportunity to buy a set that takes from 1/16 to 1 1/4" and wondered if anyone had any opinions about them. There seems to be a lot more of them about in the usa.

The Burnerd chucks usually come in what I feel is too large a size for my Boxford. I have also wondered about large ER but a key operated chuck is more attractive and the collapsible range of the rubber flex is better. I could see myself buying loads of ER40's and only ever using a few. Jacob's also reduce the grip length on the 3 smaller sizes. A plus over Burnerd. As I see it anyway.

John

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I've bought it. It makes good sense for me. I have ER16 and ER25 but currently only use these on the miller. I don't use collets that often on the lathe and prefer to make in one setting but have had to set larger sizes up in the 4 jaw a few times. I also have the boxford collets.

I've been wondering about larger sizes for the lathe on and off for some time. ER32 would give me an extra 4 mms, mixed feeling about that. ER40 larger but what a lot of collets. I had wondered about more than one collet holder and odd sizes in ER40 plus as needed going up from ER25. Don't have to worry about what sizes now. It came with a full set up to 1 1/4. I think that the larger size that is sometimes mentioned needs a different closer in the holder.

It is the T bar type and I just tried closing the 1 1/4 to 1 1/8. No problem really but I can see how it would be very easy to over tighten as the rubber deformation does take some effort. Not all that much but as it didn't stiffen as the collet closed the rubber looks to be ok. I suspect I'll find something like just grips work plus a 1/4 or less turn is fine.

I'm well aware of the need for a back plate that fits rather well. It's for the Boxford which is currently off line. That came with a dummy spindle nose but it wasn't really made to the required accuracy so I will need to make another. My aim is to always to obtain a extremely light interference fit on the spindle register and a close fit on the thread as well. That's not too difficult to do with chasers. That means size on size to maybe a 1/10 or so clearance for the register on the spindle. I suspect Jacob's suggest a very slight taper on the spigot to go into the chuck register for a force fit.

Now some one will tell me they have had one and that they are terrible.

John

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I just measured the largest collet. It is 1 3/8" and actually around 0.025 over. I've seen mention of versions that wont take that size somewhere.

Thanks Michael.

John

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I have considered a full set of ER40 right up to the point of actually buying but the lack of an answer from the seller prevented me from going further. Not a happy choice – far too many collets cluttering the place up and mostly not used especially in respect to all sizes.

I can see myself having both an ER16 and an ER25 collet chuck on one lathe at some point and probably not bothering with the ER16 and just keep that for milling but like most things I tend to wait until I actually have a need or something well priced turns up. eg The Jacob's chuck.

What would be nice is a lathe with a big bore spindle and a full set of proper lathe collets but having seen the likes of what DSG, Lang and CVA offered in that line no chance and an extra ordinary number of collets at a very high price – if they were available.

I do have a full set of Pultra collets, glad it came with some where to keep them and that they are small.

John

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