# The 8 inch Bison Combination Chuck is alive



## Bamban (Apr 4, 2018)

Months ago when MKSJ alerted me of such a deal on the Bison combination chuck, I managed to snag one, but it sat for months still in its shipping wood box. Last week reading and following Paco's thread on his ACRA lathe, he posted that he transferred his Bison Combo to the D1-6 backplate for the ACRA. Since he freed the D1-4 backplate he used with 1440 lathe, I asked if he were willing to part with it. My SBL 13 has a D1-4 spindle, I thought the combination chuck would be a perfect fit for it. Paco offered up his backplate for a very reasonable price, so we struck a deal.

It took 2 business days for the priority box to get to Austin from Tucson. Mounted and tested the backplate for runout, near perfect, bolted the chuck to it, runout just the same. Set up the jaws and dialed a 1 inch precision rod from Pacific Tool and Gauge to near zero.

Finished turning down an AR15 barrel from a 1.25 blank, no follow or steady rest, using the combo chuck. 






The combination chuck is right at home in the SBL 13.


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## Bamban (Apr 4, 2018)

Ray C,

Did you notice how the QCTP is kicked back to the right, took note of your post in one of the threads how a subtle set up could lead to chatter. Well, you are right, followed your lead, and bingo....


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## Ray C (Apr 6, 2018)

Bamban said:


> Ray C,
> 
> Did you notice how the QCTP is kicked back to the right, took note of your post in one of the threads how a subtle set up could lead to chatter. Well, you are right, followed your lead, and bingo....



Every little bit helps.  In your case, the carriage legs are pretty wide.  If moving the QCTP toward the center helped reduce chatter, you may want to inspect the cross-slide and compound dovetails.  Maybe snug them up just a little bit.


Ray


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## middle.road (Apr 6, 2018)

Boy, that carriage compared to mine is like comparing a 1969 Cadillac to a VW Bug...


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## Silverbullet (Apr 6, 2018)

If I had to have only one chuck this would be it. Independent four jaw with three jaw quickness. It's beautiful piece of workmanship. Looks good on your lathe too.


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## Janderso (May 2, 2018)

Mr. Bam,
How did you find a D1-4 backing plate with I assume 1 7/8 8 tpi thread?
Your 13 has the cast iron bearings. It’s old school like mine.
I didn’t know that was possible.
Nice chuck,let me just wipe the druel off my face.


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## Joe in Oz (May 2, 2018)

Did you read the first post?

Cheers, Joe


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## Bamban (May 2, 2018)

Janderso said:


> Mr. Bam,
> How did you find a D1-4 backing plate with I assume 1 7/8 8 tpi thread?
> Your 13 has the cast iron bearings. It’s old school like mine.
> I didn’t know that was possible.
> Nice chuck,let me just wipe the druel off my face.



My SBL 13, a 1956 build,  has a D1-4 spindle, I got the backing plate from firestopper when he had to change backing plate to D1-6.

I actually have bronze shims on my lathe.


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