I have been looking for a Set-Tru 3 jaw 10" scroll chuck for quite awhile, mostly for when I am turning large diameter stock with a fair amount of stick out. I have a 3 jaw 6" scroll PBA Setrite (UK version) that I use quite a bit and had been looking for a 10" PBA or Bison/TMX. Prices in past years was much more reasonable, but the pricing of the 10" chucks has almost doubled in the last couple of years. The Set-Tru back plates are also quite expensive, in particular the forged steel ones. Recently an eBay seller had two Bison forged steel 10" chucks and they just happened to also include the 10" D1-4 Set-Tru back plate. Not inexpensive but 1/2 the cost if I bought both from an online store. Was a bit worried when it showed up as the box was trashed.
Didn't come with a chuck key so I made my own out of O1 steel, oil hardened the key, pressed in the T-bar and then blackened the surface. Chuck mounted up well and was able to zero the TIR, it is quite a nice chuck but at about 100 lbs with the back plate a bit much to lift up into position. Next project is to make a sled for the ways, just a bit too awkward to mount otherwise and have it role down on my foot.
Chuck spins up smoothly but my the VFD groans a bit coming up to speed, it also brakes it down to a stop in 1-2 seconds, faster than my manual brake. Without braking the chuck spins for a very long time before stopping. Chuck is very well balanced with no lathe vibration at spinning the chuck at speed. Bison/TMX chucks are very nicely made an accurate in my experience. This is my 3rd Bison chuck.
Was not impressed by the sellers packing, surprised the chuck didn't fall out of the box.
So much for the original styrofoam packing.
Run out zeroed down to around 0.0001" with a precision ground rod with no change at different measuring points. Chuck key I made from 3/4" O1 steel with a 14 mm square key, it make my other chuck keys look like toys.
About as big a diameter as one can go with a D1-4 mount. Back plate is by TMX, which is interchangeable with Bison. Stub pins appeared to be hardened, still a lot of mass when it gets going.