Set Tru Bison Chuck Question

[r2784c]

All,

Recently purchased a used lathe that had a 6" Set-Tru Bison Chuck on it. The Top jaws were missing and unfortunately one of the master jaws is damaged. Before I drop 1k on a replacement parts for a 2012 chuck, I disassembled it to take a look at the condition of the rest of the components. Attached are two pics of bearing surface of the scroll plate. I don't have enough experience to know if this is too much wear to bother with a rebuild. Any thoughts?

I would prefer to just to grab a bison 4 jaw independent chuck, but adapter plates for my A2-5 spindle are running 5 month lead time.

Thanks

 

[Jim F]

Clean it, lube it, use it.

 

[mksj]

The wear on the bearing surface does not seem to be bad, but I would worry about wear on the scroll and getting new parts it will hold tolerance over the scroll adjustment. If you need to spend 1K and end up with something that will have questionable repeatability and probably need the jaws ground in place, I would invest in a new 3J scroll adjustable chuck.

I use the PBA Setrite on mine, which run just over 1K, a new Bison Set-Tru around 1K. If you have the back plate for your damaged chuck, why not just get a new chuck body.

6" BISON 3 Jaw SET-TRU Chuck Forged Steel 7-866-0600

PBA 6" 3 Jaw SETRITE Lathe Chuck 0625300

 

[r2784c]

Yeah, that is what I am struggling with. A replacement bison 6" set-tru is 2k, without adaptor. I don't need a set-tru, but as I mentioned lead time to get a 4 jaw steel independent with adapter plate is 5 months. I was going to move up to 8" and would need the adapter. Not sure if I stuck with 6" chuck if the adapter plate I have now for the damaged set tru chuck would work with a 6" 4 jaw independent. Guess I will give them a call tomorrow.

 

[r2784c]

Sorry, should have mentioned the set tru I have now is 4 jaw, not 3. much more $

 

[mksj]

I must not be following something, a replacement 6" scroll forged steel set-true type chuck from Bison sells for 1K. If you have the back plate from your used chuck it should be the same as a new chuck and save you some $$. A set-True type chuck back plate/spindle adapter plate will not work with standard chucks. Sometimes there is some cost savings in getting a spindle adapter plate from say Gator vs. Bison/TMX as they are less expensive and often interchangeable. Worth asking.

You might look at this site, they seem to indicate that they have a range of A2-5 adapters for different style chucks in stock.

Lathe Chucks and Back Plates | carbideanddiamondtooling.com

 

[r2784c]

The model number of the chuck I have is 3765-6". From Bison website, the part # is 7-847-0600. Cheapest price I saw on the web was 2k from ajax tool supply. That is why I was thinking of rebuilding. New is very $$

 

[mksj]

OK, my concern would be what happened to the chuck to be missing those parts, I would figure it was probably involved with a carriage/tool crash, if so there would most likely be damage to other parts of the chuck. You would need a matching set of master jaws/jaws and I do not think the scroll repeatability would be there across the clamping range/ and or the jaws would need to be ground in place. A lot of $$/time with unsure results.

I use a Bison 8" combination 4J chuck which gives me both a scroll and independent jaws. Repeats to approximately 0.001" on the scroll and then you can dial down the TIR by tweaking the jaws. I use to use it quite a bit, but it is heavy, so I use it less frequently. It holds stock sown to 0.2" and it holds it very true. Price wise less than the 4J scroll, I am using an 8" Gator back plate which was 1/2 the cost of the Bison.

 

[r2784c]

The missing top jaws were due to a custom fixture being mounted directly to the master jaws. The fixture was still mounted on the chuck when I got the lathe. The damage on the master jaw, I can't explain. The tenons were sheared off of one of the masters.

I hate to ditch the chuck if it can be salvaged, but I have similar concerns that the end result will be less than satisfactory

 

[mattthemuppet2]

send me the dimensions of the master jaws. There's a slim chance I might have a set, certainly the shop I got most of my tooling for sale from used alot of Bison chucks (I have an 8" non-set tru I need to put back together).