Well I got the chuck today, typical China quality...well I've had China chucks they were better out the box. The one I received does not open & close very well out the box. It's very tight & "gritty". Well of course it is, the damn scroll & jaws are covered in grit & tiny shavings! Like any Asian import chuck I've had I always completely disassemble them, clean, & deburr before using.
As I suspected it is 6.25", well 160mm/6.3" to be exact just like my Bison. The through hole is 1.75" which I didn't think it would be. The jaws are able to grip down to 3/16", my Bison 6-jaw only gets down to 3/8".
Here's something that I don't see often, the pinion faces have a bare machined finished (no functional importance of course).
The one I got the jaws don't mesh near as well as my Bison, you can see the two jaws in the lower right corner is even worse. Not sure if it was a grinding issue or if it's because of all that crap inside of it. Hopefully it does clean up & goes away.
Since I bought this to use on a rotary table I have no way of measuring run out since I don't have a backplate for it & I won't be making one for the lathe. My 3 jaw that came with the lathe is 6" so the backplate is too small.
I decided to try something, not something I would trust as there's too much error involved but it gave me a rough measurement with what I had on hand.
I chucked up a piece of Thomson shafting that I use for checking runout in the 4-jaw & indicated. Was going to try clamping the 6-jaw on the end.
Not sure why but I was getting weird readings so I decided to try the same with my Bison which worked better.
I estimate about just under .002" runout, measuring the register on the back & the body was about the same. The register is not machined very smooth. Crappy phillips screws holding the back cover & set screws for the pinion but no surprise there. Typical cheap tiny chuck key which I always just toss in a box anyway. They did include a microfiber cloth with machining related pics on it for cleaning, never seen that before.
So my thoughts on a quick evaluation, typical you get what you pay for with Asian import stuff. Will I keep it? Yes. Would I buy it again knowing what I know now? Probably not, but with some work it might turn out to be a decent chuck, good enough for me to use on the rotary table anyway. We'll see after I spend some time on it to go through & clean up everything, I'm a bit scared to see what it looks like inside.
The Fuerda/Gator semi steel 6-jaw would be a much better buy for a couple hundred more & it's adjustable.