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skipd1
04-16-2019, 04:17 PM
I am looking for a 6" set tru 3 jaw scroll chuck for my South Bend Model O Heavy Nine lathe. I currently have a no name chuck that has quite a bit of run out and I have a Buck 6" 6 jaw set tru that I really love. I also would like to have the jaws removable so I can make some soft jaws. I see a few nice Bucks on Ebay from time to time, but really pricey. All the Bison brand set tru chucks I've seen are completely out of my price range as a home hobbyist. I have also heard that ToolMex or TMX makes a decent set tru chuck as well. I also don't really want to go to a 5" chuck because I need all the capacity I can get. Any ideas or are there other options for Set Tru scroll chucks out there?
Thanks

skipd1

danlb
04-16-2019, 05:00 PM
Many companies make adjustable scroll chucks. The BTC brand that I bought sells one using the trademark of "Zero Set". It has 4 adjusters in the body instead of the 3 that are common with most. Some searching for alternate ways of saying "set tru" may work for you.

It seems that none of them are cheap.

Toolguy
04-16-2019, 05:08 PM
What is your spindle mount type and size?

Arcane
04-17-2019, 12:11 AM
I lucked out when I bought a small Atlas lathe for resale. It came with a Buck Adjust Tru chuck so I swapped it for the plain 3 jaw chuck on my 9" SB.

skipd1
04-17-2019, 09:54 AM
The mount is plain back with 1 1/2x8 tpi.
As long as the chuck takes a plain back I can make one if it comes with something different

old mart
04-17-2019, 04:10 PM
I couldn't possibly afford a set tru type of chuck, so just turned down the register about 0.015" diameter. With rear mount chucks having three bolts/ shcs holding on to the backplate, I simply drilled and tapped for three more for security. With clearance holes in the backplate, it is just a case of slackening the bolts just enough for a nylon hammer to tap the chuck in line with the spindle and tighten up the six bolts/screws. Friction takes care of the lack of a tight register. After all people rely on friction between the jaws and the work, and also it works quite well on milling machine tables.

gzig5
04-21-2019, 08:14 PM
Set-tru chucks usually have a specific or non-standard back plate that has a raised register for the four set-true adjustment bolts to bear against. If you can't find or afford the specific back plate you need, a standard flat one can be modified by adding an appropriately sized donut shaped bit to the front side.

Illinoyance
04-21-2019, 09:50 PM
Buy a cheap chuck with 2 piece jaws. You will bore the soft jaws in place so concentricity and adjustability would not be an issue.

J Tiers
04-21-2019, 10:26 PM
Buy a cheap chuck with 2 piece jaws. You will bore the soft jaws in place so concentricity and adjustability would not be an issue.

But, you run out of jaw eventually, sooner if the parts you chuck are rather different from the previous ones.

The set-tru just keeps on working.

Most of the backplate blanks have enough meat on them to allow making the screw pusher nose integral. But where those blanks used to be about $15, now they have gone up to as much as $50 or more.

Paul Alciatore
04-23-2019, 07:18 AM
I have a SB-9. I purchased a Bison standard three jaw with interchangeable top jaws and made my own back plate with four set screws for adjustment. It wraps around the outer edge of the Bison chuck and I just loosen the six mounting bolts a bit and center it up. Then tighten them again. You have to buy or make a back plate anyway.