Chuck Mandrel for a small 5” 4-jaw Chuck

[Paul Jones]

PJs,

You have a good concern about running the 5" 3-jaw chuck on a mini lathe with a 7" swing. I know others had simialr concerns when I first published the article about mounting the chuck on the mini (see http://www.homemadetools.net/forum/a...4269#post18042 ). I could not see any reduction in power (monitoring the RPMs while machining is the main reason I installed tachometers on my lathes) but the extra mass really helps with the rotational momentum and I don't think the extra mass is harming the headstock bearings. This is no longer an issue now that the mini is run win an ER32 collet for most work and no need for the 5" chuck on the mini lathe.

I bought the 5" Bison 4-jaw chuck in 1993 and it didn't seem too expensive at the time but Bison chucks today are pretty expensive. Last year I bought an 8" 4-jaw Fuerda/Gator D1-4 mounted chuck for the 12' swing geared head lathe and found the quality to be excellent. There is great story at Practical Machinist about how the Fuerda/Gator company was started and the quality control used to inspect their chucks (see A story about Bison & Fuerda (Gator) chucks ... ). This Black Friday, I ordered a 6" 6-jaw set tru Fuerda/Gator chuck at a considerable discount and looking forward to making it my main chuck on the 12" lathe.

Paul