I am trying to respond without being derogatory about how you tighten such a chuck. In that, I want to say a lot more than I actually do. A chuck like that should
never be closed with a heavy tool. Wrenches, channel-locks, anything heavier than the correct "tommy bars". It is for "light weight" work only.
I have a 3 jaw that was on my Cr'man 12X36 (101.27440) when I acquired it. It uses a 1/4" key to tighten, so I set it aside as "non-standard", for me. I use several chucks, depending on what I'm doing. The 1/4" key would fit only that chuck, nothing else.
The chuck you picture looks a lot like what was on the UniMat, just bigger. I still use the (3") UniMat chuck on occasion. For small work, obviously. I also use the 3"-4 jaw when it's called for. Such a small chuck on a large machine looks silly. But appropriate for what I use it for.
Perhaps we should work up a "horse trade", one for the other. A practical solution from my perspective. Yours? The only thing I would have trouble with is boxing it up for shipment. If you would be interested, send me an eMail separate from the board. I'll try to get a photo into my computer so you can see what it looks like. Spindle thread 1-1/2 X 8, Body diameter 5" (appx), Key 1/4", same as a small socket set driver.
bhudson@hudsontelcom.com
Bill Hudson
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