8" bison 4 jaw mounting

[kpschafer]

So Ive got a Bison 4 jaw independent chuck. I held onto it when I sold my last lathe as it was still in great shape and something I regularly used. The old machine being a 1-1/2" 8 thread spindle. I'd like to find a backing plate to mount it my new lathe but it's got an odd ball spindle from what I can tell and only came with 2 chucks and I have to use 1 backing plate between the 2.
The spindle is a 1-3/4 with 8 tpi. I can't seem to find a backing plate for a chuck larger then around 6".
My lathe is a 13" x 54". I can't imagine an 8" chuck is to big to use.
Any help would be great.
Thanks guys.

I forgot to mention on my old machine whoever machined the backing plate made it so it was only the diameter of the smaller inner recess on the back of the chuck. Not the larger recessed area. Is that correct mounting?

 

[piper184]

As I understand it, the less mass at the end of the spindle the better. That is why usually you see a larger diameter 4 jaw than a 3 jaw for the same machine. Without the internal scroll and associated gears, the larger 4 jaw probably weighs about the same as the smaller 3 jaw.
I don't see any advantage of having a backing plate that is larger than the smaller register diameter. It just adds weight and length (stick out from the spindle), both of which you normally want to keep as low as possible.

It looks to me like that would be a fairly simple backing plate to make using one of your other chucks. Just leave a little room for finish cuts for after you spin it onto the spindle. That way you are going to get the best possible fit to your spindle. Face it off nice and square, then turn down the final diameter for the registration and the chuck body should have very little run out.

Does the spindle have a place to register the backing plate? If so, that will probably be the most difficult part to get exact, but once it is fitting properly, the rest will just fall into place.

What make and model is your lathe?

 

[rwm]

I have that exact chuck with an integral D1-3. Yes, I think you only want a back plate that has the smaller ID. The rest of the chuck can be exposed. In fact, if you use a larger back plate, you want to make sure it does not touch outside of that small diameter or it may distort the chuck body and the jaws will not move correctly.

 

[woodchucker]

$79 at CDCO for a
5" 1-3/4 x 8 For 5C Chuck just make it work for your Bison as others have said. I have one of their backplates, and in 2013 or so it was good quality.

 

[kpschafer]

As I understand it, the less mass at the end of the spindle the better. That is why usually you see a larger diameter 4 jaw than a 3 jaw for the same machine. Without the internal scroll and associated gears, the larger 4 jaw probably weighs about the same as the smaller 3 jaw.
I don't see any advantage of having a backing plate that is larger than the smaller register diameter. It just adds weight and length (stick out from the spindle), both of which you normally want to keep as low as possible.

It looks to me like that would be a fairly simple backing plate to make using one of your other chucks. Just leave a little room for finish cuts for after you spin it onto the spindle. That way you are going to get the best possible fit to your spindle. Face it off nice and square, then turn down the final diameter for the registration and the chuck body should have very little run out.

Does the spindle have a place to register the backing plate? If so, that will probably be the most difficult part to get exact, but once it is fitting properly, the rest will just fall into place.

What make and model is your lathe?

From what I have gathered this far it is a very early Tornos Nodo 160. No info on it even from the manufacturer.

 

[kpschafer]

Can anyone give me any info on this?!?

I'm driving about 3 hours away to go take a look at this machine in a couple days. Seems to be a well built vintage lathe(given my limited knowledge anyway). My issue is I can't translate or find any info anywhere on this thing. The owner inherited the think from a neighbor or something along...

www.hobby-machinist.com

The thread trying to identify it.

 

[stupoty]

I have my 10" 4 jaw mounted with the inner recess.

plz excuse surface tarnish , it's getting wintery around the UK.



Stu