I also have a 2J collet chuck for both D1-3 and, D1-6 spindles along with collets, rounds by 64th's to 1 3/8[.]
-Noice! I'm a big fan of collets on the smaller lathes (5C, of course) and wanted the capability on the big Springer too. I'd been keeping my eyes open and by random luck, I recently picked up a low-miles Hardinge/Sjogren 3J, with 19 Hardinge round collets (roughly by eighths, with a few sixteenths in there) for just under $300.
One of these days I hope to get the damn lathe back together so I can actually use it.
drill chucks to a 1" supper chuck.
-A Supper Chuck is when grandma throws the Christmas turkey at you, isn't it?
I'm kidding, I'm kidding!
I'm a fan of Jacobs Super Chucks too. I have a couple keyless around here somewhere, but 90% of the time, I'm reaching for one of the pre-Chinese Jacobs.
Left to right, a 14N on an R8, a 16N on an MT4, an as-yet unassigned 18N and a 20N also on an MT4.
And in case anyone's interested in how big a Jacobs 20N chuck is...
Keeping in mind I have Desert Eagle sized hands.

That has a max capacity of an inch.
I would love to talk to some guys that have small lathes like this , I am a hobbiest , not a machinist.
-Ask away. Most of us started out with small lathes. My first real lathe was a Grizzly 9x20, used that for a couple of years before I replaced it with a Logan 11x32, which is still a small home-shop sized lathe.
I may talk about my big Springfield, but that's basically a side project. I do all my paying work with the Logan and a 10x56 Sheldon.
It has in interesting drive mechanism - 4 pulleys of different sizes and a disc of unknown material that sets into the pulleys to drive it.
-Huh. Never even heard of that make or drive style. On one hand it seems it'd be pretty fast and easy to change speeds, but on the other it seem like it'd be very limited on how deep a cut could could make.
Am I wrong in thinking that's an eight-speed headstock? Two discs on the motor and four pulleys on the spindle? That's also a gear-reduction motor, isn't it? Interesting setup...
Doc.