# Pm1236 - New Bison 8" 6-jaw Chuck Installed



## JayBob (Feb 24, 2015)

Ever since I upgraded from my MicroMark 7x14 mini lathe, to the PM1236.  I was disappointed with the size of the chuck.  I had a 5-inch chuck on the little MicroMark, but only a 6" on the 1236.  I don't do a lot of bigger parts, but I do have some parts that I sell, made from 6" O.D. UHMW, that I wasn't 100% comfortable with in the 6" chuck.  I used to have some.....interesting.....methods of chucking it up on the little 7x lathe.  lol.  I also really missed having the reversible jaws like the lathe I used to use back in the Navy.

For those that are wondering, I got the chuck on ebay, and the backplate came from Grizzly.  The chuck was "new, unused stock", and was an even $1000.  It's a Bison 8" 6-jaw Set-Tru.  They had it listed at $1549, but I offered $1000 and they accepted it.  I found later that Grizzly sells it here (http://grizzly.com/products/8-6-Jaw-Set-Tru-Chuck/T10421) for $1065 shipped, and that's the absolute best price I could find anywhere.  Grizzly also had the best price on the backplate here (http://grizzly.com/products/8-D1-4-Back-Plate-for-Set-Tru/T10429) for $297 shipped.  I think I found a 5% off coupon too for some holiday. 

I was a little worried about it possibly hitting the chuck guard, but with the jaws extended as far as I would ever comfortably extend them, I still had plenty of room.

Anyway, here's some pictures, cuz we all love the 6-jaw chuck porn.....  Sorry they're not very bright, and the lathe is pretty messy.  I do a lot of Delrin and UHMW work, and that stuff gets everywhere.  The shop vac usually cleans it up pretty well, I just haven't done it for a while...

Also, I forgot to take any pictures dialing it in with the Set-Tru adjustments, but I went ahead and made an excuse to buy a new Noga mag base, and an import .0001" indicator.  I got impatient waiting for the indicator to come in, so I ended up borrowing one from another user on here: Morgan_Redhawk.  Thanks, Morgan!

The backplate.







The Bison 8" 6-jaw Set-Tru chuck.


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## wrmiller (Feb 24, 2015)

I'm considering a 8" 3-jaw set-tru for my 1340GT, and one of the major reasons is that I already have a 5" set-tru on my 8x18 and only putting a 6" on a lathe nearly twice the size seems kinda stupid. I talked to Matt at PM and he says the lathe will handle it easily, but that he prefers a 6" for some reason. He says it's just personal preference. It (8") only weighs 44 lbs so I'd be surprised if that was the reason.

Oh...and nice chuck.


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## Morgan RedHawk (Feb 24, 2015)

Yeah man, that's pretty sweet!


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## darkzero (Feb 24, 2015)

wrmiller19 said:


> I talked to Matt at PM and he says the lathe will handle it easily, but that he prefers a 6" for some reason. He says it's just personal preference.



Yeah, I prefer the 6.3" chuck also for primary use on my 12x. I had seriously considered an 8" but changed my mind & it wasn't due to the price as they were cheaper back then. Not sure what Matt's reasons are (I never thought to ask him Test) but weight does have something to do with my reasons & it's not weight as in having to carry it. I do however wanted my 4-jaw to be 8" though. Either way, either size will be perfectly fine.


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## coolidge (Feb 24, 2015)

I almost went with an 8" but I'm glad I purchased the 6.3", darkzero talked me into down sizing.


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## tmarks11 (Feb 24, 2015)

I prefer 6" because it is so much lighter and easy to change.

The heavier the chuck, the more reluctant you will be to swap it out, and the more likely you will be to make compromises that affect part quality because of sheer laziness. I like that I can pick up a 6" 3 jaw with one hand (and my 5" Bison 5C chuck is featherweight).  Most of the work I do is with stock that is 2" or smaller in diameter, so a larger chuck is not needed.


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## wrmiller (Feb 24, 2015)

If I had only one lathe, I probably would go with a 6". Maybe. But then again if I had to have only one chuck (or just didn't want to change chucks), I'd want one that can do both small and larger work. Then I don't have to worry about changing chucks unless I need a four-jaw. But if I need a four-jaw, maybe I can just do the job on my mill. 

As many have said, it all just boils down to personal preference. I may have to someday plunk down the cash for a six-jaw though, as they do look really cool. LOL...


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## gt40 (Mar 5, 2015)

Congrats on your 8" chuck!

I have a Bison 6" 6 jaw and a 8" 4 jaw independent import for my Jet 13x40 lathe.  Hardly ever use the 8" - I am too lazy.

Sometimes though, size matters- I found that out when converted my PM45m to cnc and added a 4" head extension. As a result, I have 11.5" of Y axis travel on my Precision Mathews PM45M.  I cut a lot of the parts in the conversion on the lathe and the 8" chuck.






I cut all the bearing blocks for the cnc conversion with the 8" chuck on the lathe to make them perfectly concentric and square.


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## wrmiller (Mar 5, 2015)

Very nice! 

My chuck showed up today. While the chuck only weighs forty something pounds, I forgot to factor in a thick steel mounting plate. I'm fairly certain that once I get this thing mounted it's going to stay there.


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## darkzero (Mar 5, 2015)

Very nice Mark! I really need to get out there again so I can see your Jet, haven't seen it since before the conversion. Would also like to see what new things you have done to the PM45 since.

Will you be keeping the Jet orange or will it get painted to match the mill?


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## gt40 (Mar 6, 2015)

The orange is growing on me 

Here is a vid when I first got it going: 




Let me know when your down this way.


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