Question Re Camlock Chuck Fixings

I have recently swapped out my Colchester Student lathe with L0 chuck fixing and replaced it with a Colchester Triumph 2000 which has D1-6 chuck mount on the spindle. I have the standard 12" 4 jaw, and 8" 3 jaw chucks as well as a Burnerd Multisize chuck.

I had a 6" Burnerd GripTru chuck on the Student which has a backplate with the L0 fixing. I wish to be able to use this on the new lathe and so need to replace the L0 backplate with a D1-6 camlock backplate. I have been looking on Ebay and there are quite a few D1-6 camlock backplates available for chucks around the 6" to 8" diameter range but they all appear to only have 3 camlock pins rather that the full 6. Can a 3 pin fixed chuck work as safely as a 6 pin mounted one? The only 6 pin one I can see on the market at a reasonable price is that marketed by RDG, although that ideally needs turning down from the supplied 200mm to be closer to the required 6" diameter.

Any thoughts,

Thanks,

Colin

Are the advertised back plates just showing a generic picture of a cam lock and not the actual article ?

IIRC the late Sir John Stevenson of this parish used to run D1-6 with only 3 pins in it.

The pins pull the taper together. 3 is most likely sufficient for most uses.

Somewhere on the internet (might be the home shop machinist bbs site) there is a long discussion about this and how 3 pins are plenty enough based on the strength of them.

Dave

A small amount of poking later : **LINK**

John was running D1-5 not 6, but the principal is the same

Dave

My 8" 3 jaw is held by three D1-3 pins. I see no problem with holding the same size chuck with 3 of the much stronger D1-6 pins.

I use a 250mm ( 9.75" ) on 3 x D1-4 pegs on my Warco GH 1332 without issue so you should be fine.

Edited By Henry Brown on 28/04/2022 17:49:46

Hello, I purchased my D16 backplate from Chronos , excellent quality and 6 pins , for an E40 collet chuck adaption. Good service too.

Thanks for the responses. I had hoped to put my 6" Griptru chuck onto the D1-6 backplate. When I tried to remove what I thought was the L0 backplate, I very quickly found that it was an integral part of the chuck. Oh well, that is another chuck I need to try and sell along with my Burnerd Multisize collet chuck.

Thanks,

Colin

L0 chucks sell quite readily. I don't think you'll struggle with that.