Cleaning and restoring a set tru Bison

[Beckerkumm]

I've been watching for eithe Buck Adjust tru or Bison set tru 12" chuck for my Monarch 16" lathe. I have a 12" independent and a 10" Bison combination four jaw which is my go to chuck. I don't have a very good three jaw so I've been watching for a three or six jaw but not wanting to cough up $3000 for something I don't need often. Over the past year I found a couple of D1-6 backplates for under $150 as finding a chuck with the correct plate is like winning the lottery without buying a ticket. Recently I found a listing for a six jaw chuck off a Haas CNC machine. The chuck wasn't labeled but I knew from the numbers that is was a 12" Bison Set Tru. My concern was that the guts of the chuck might be rusted from coolant from a CNC so I offered $800 unless the seller was willing to take the chuck apart and show the inside. Got the chuck and it did have some rust on the gear side of the scroll. Bathed it in evaporust and cleaned everything up.

My question - finally - is how to lubricate. I'll use oil on the scroll and jaws but wondering of some type of grease might be better on the gear side. It is shielded from most chips but I'd like opinions on what makes the most sense.

Dave

 

[petertha]

I found this Bison document. If you do a Ctrl-F on 'lubricate' it specifies their recommended procedure. I find it a bit convoluted which is probably why its not sticking in my brain. Primarily grease on all the surfaces, but they mention frequent higher frequency oiling on the scroll via the nipple in the case of 'heavy operating conditions'. I always assumed oil/grease it was an either/or selection except in the case of assembling components. If you can make more sense of it than me, I welcome your comments.

https://bison-chuck.com/wp-content/uploads/2021/06/Manual-3200_3500-1001-01.pdf

BTW, I just posted this regarding my Bison Set-Tru, you might find it interesting.

Adjust-Tru Bison

I was looking at this recently myself. I bought a Bison 5C Set-Tru at Ajax. At the time I found their prices to be pretty competitive on new. The 6"-6J Gator works out to 1195 USD including D1-4 Adjust-Tru backplate https://www.ajaxtoolsupply.com/6galach6jawt.html The Bison 6"-6J forged...

www.hobby-machinist.com

 

[Beckerkumm]

I've read disagreements over Bison's recommendations enough to question them. I used grease in the past as they posted but agree that it is a chip magnet and generally avoid grease on any other machine as oil seems to be a better solution. Putting grease on the underside of the scroll for the gears does seem to make sense but I'm really just blowing orifice smoke here as I don't have a clue. If grease, what type would be the best choice, if oil, same question. I would think the gears would like something tacky and heavier than would go on the scroll or jaws. but given they all spin, maybe heavier is better ? Dave

 

[petertha]

I don't like grease where chips can get embedded either. OTOH I find the most viscous oil I have handy, way oil, tends to migrate out of even slim openings between surfaces under centrifugal force. And over time I notice it goes kind of darker brown & molasses in nooks & crannies.

I'm experimenting with grease right now on a little 3" Chinese chuck called a Harlingen. Its not a Bison, but its decent for the money & Bison would probably charge $450. (There are similar Chinese ones which are brutally bad but that's another story, this one has about 0.001" TIR). Anyways, one can/should clean, deburr & finish all the offending edges, but you can only 'smoothen' these forged pinion gears. Grease really does make them feel better. A light coating is all you need, packing it much more isn't productive IMO. I just don't see much downside to grease unless there are open gaps for swarf to enter & stick which is bad. 4-jaws screws are probably more exposed in this regard. When I was playing around I added a few drops of way oil onto a sample of grease just to see. It doesn't really make a thinner grease or thicker oil, it basically makes a non-soluble mess so I don't really get that aspect.

 

[Beckerkumm]

Thanks. The fit of the scroll fit is pretty exact to the housing so I don't think grease will migrate out. I will oil the scroll top and jaws. I'm thinking my #2 way oil would be OK. I don't know if light or heavy is better. I have some very heavy gear oil 600w for my Moore Jig bore but that is like molasses and I fear would be similar to grease as an attractant. Dave

 

[mattthemuppet2]

I've always used grease on the gear and pinions, then way oil on the scroll and jaws. Wrap a plastic bag around the chuck first time you spin it up to catch the excess

 

[Beckerkumm]

That is what I ended up doing. I also skimmed the back plate as I get about .0006 wobble on myD1-6 mating area. I also mark the chucks to install the same way. Chuck is now so smooth I'm taking all of mine apart and cleaning them. Probably about time. Dave

 

[Beckerkumm]

Chuck is now on the monarch and adjusted to .001 repeatability. Three jaws are within a few tenths but the fourth has .001 so it might be me.

I also tore apart a used Buck chuck I bought mainly to have set with outside jaws as removing jaws on my combo chuck is a pain. I have mainly Bison chucks and am impressed with the build of the old Michigan Bucks. The gear plate and bodies are heavily built. The adjust tru back plate is held by 6 screws vs three on my Bison and the newer Buck chucks that ae made overseas. The only negative is it only has one gear to tighten vs three on my Bison. Only one insures that it will never be located where you want it. Life is a compromise. Buying used chucks is risky but if you find one that looks good, the old Buck is well built.

Dave