What is this thing on my lathe? Any ideas?

[djb25]

Hi everyone,

I recently purchased a Clausing 5904 that came with an odd piece mounted on the spindle. I would say it was a chuck, but it doesn't actually seem to have any function. I'm curious if it may actually be a part of some larger assembly.

Here's a shot of the the item in question, shortly after unloading:



It's actually a round disc attached to a Bison backplate. It's pretty nicely machined and has a nice, tight fit with the backplate.

Here's a shot of the back of the item, after removing the backplate:




The seller told me that the lathe had been used exclusively with collets before it was removed from the machine shop. It sat for about five years before I bought it. I'm thinking that it might be part of some sort of collet closer?

After cleaning the thing up in the electrolysis tank, a distinct mark was visible on each side of the nose:



Any idea what this thing is?

 

[Don B]

My guess would be an adapter for different chucks that where meant for a different machine, I have one I made that is similar to it for mounting my Emco 3 jaw on my Myford.

 

[chips&more]

If there are four opposed marks on it it was probably used for a self-centering chuck. The large center protrusion and marks are typical for said chuck. And I think it’s shop made and just a chunk of metal, I wouldn’t sweat it unless you have a chuck that would work with it. And you made a nice score, I think you will be very happy with that particular lathe, it’s very desirable. If you read some of the forums on its vari speed assembly, you could easily get a bad impression about the design of it. I find that forum talk a bunch of folks with no/limited knowledge on its modulus operandi and just want to make noise. If you need any assistance you can PM me…Good Luck.

 

[kd4gij]

Is the bore tapered.

 

[billdeme]

I may be wrong but ut looks like a collet adaptor. The "bruise" marks are from the centering set screws.

 

[darkzero]

Looks like just a shop/home made adapter for an adjustable chuck (ie Set-Tru, Adjust Tru, Setrite). The marks on the nose is where the chuck's adjusment screws make contact with the adapter to adjust the TIR.

 

[billdeme]

Either was its an adapter plate of some sorts. The chuck in question was definitely adjustable due to the marks. Being the seller stating it was fitted exclusively with a collet set I would lean that way. My Cincinnati hawk is fitted with an adjustable collet set to remove any spindle to collet run out.

 

[Vladymere]

It looks like the back side of my Prat-Burnerd set true chuck. which is sandiwiched bettween the chuck and the L00 spindle backplate.

Vlad