8" Chuck on Heavy 10L

Hello, I'm new to the site, I recently bought a disassembled heavy 10L and I'm in the process of gathering missing parts to assemble it. The only reason I bothered with this is because the previous owner had the bed milled and the saddle fitted with turcite. Apron, headstock, and tailstock were worked on and everything looks really good, no play whatsoever in the tailstock, etc. However, no tooling, no change gears, and a few other small things. (This is one of the models without QC gearbox) My question is regarding a chuck. There's a brand new 8" TOS chuck at work that I can have for free, but I'm concerned it's too heavy for the lathe. I'd use the 8" just to get going before I eventually get a smaller one, so I'm not asking if it's an appropriate chuck, I'm more concerned about actually overloading the headstock bearings etc. By the time I make a backplate and mount the chuck, will it be too heavy? Too much overhang? Or can I use that setup to get going just to take some test cuts, fool around with it, and make sure everything works the way I want before I spend more money on a proper size chuck? For reference the 8" chuck weighs about 30 lbs, and I guess the backplate would weigh 8-10 lbs. If anyone could share similar experiences or opinions it would be appreciated. Also if anyone has spare parts they'd be interested in selling I'd be interested in that too, Specifically tooling, steady rest, gears etc.
Thanks!

If its FREE, just take it! I had an 8" chuck for my old 12" lathe, realistcly it was too heavy for everyday use, but just the ticket for some jobs.

You're not making sense. You say you have a 10L, but are worried that an 8" chuck will be too heavy? An 8" was pretty much standard equipment for a 10L. You must have an earlier 10" lathe (not 10L), because I don't recall there ever being a 10L WITHOUT a QCGB (AFAIK, it wasn't even an option).

Go to Steve Wells site and use your serial number to find the approximate year of your lathe. If before 1939, it isn't a 10L.

I've been on Steve Wells' site. According to the serial number, it's roughly a 1942, and according to the letters stamped after the serial number "RCL" from Steve's chart, it means Heavy 10, Standard Change gear / Screw feed gear, and large spindle bore. However I plan to order a serial card from SouthBend so I'll confirm that later. Regarding the chuck, you're saying the Heavy 10 lathe came with an 8" chuck as standard equipment? Either way yes I'm asking if the 8" is too heavy. Maybe others can comment and let me know if they're in fact using an 8" chuck on the heavy 10 or similar.

You're correct - it seems that a 10L WAS offered with standard change gears. Just because I've never seen on (or even heard of one) doesn't mean that they don't exist. And, reviewing the catalogs, it looks like the 6" was the standard 3-jaw. But it weights 33 pounds, not much less than your 8". There are times when I needed a bigger chuck and have to dial up my 7-1/2" 4-jaw, so I would say "no", an 8" chuck will not be too heavy for a 10L. Anyway, if it's free, you can always sell it and get a smaller chuck.

I think you'll find the 8" chuck somewhat limiting because the jaws cannot extend very much beyond the OD of the chuck for holding large pieces. However, it will work just fine and the weight of the chuck is pretty small compared with the cutting forces that have to get reacted by the headstock bearings. Should not be a problem.

Good point about the cutting forces, probably I'm overthinking it. The size is definitely limiting. Once I get it going I'll be in the market for a smaller chuck.
Thanks for your reply.

One thing that 8" chuck will get you is the ability to grab the outside of large parts, like an 8" disk. The jaws will protrude, but probably not enough to be a problem at that diameter, as you have an inch of radius clearance around the chuck.

If the chuck has replaceable jaws, you can get soft jaws for it and that opens up a world of possibilities.

I have an 8" chuck for a 12" lathe that can't be mentioned, and I got it for a specific job to turn a profile into the face of an 8" disk. The jaws hardly stick out. The issue I will have is the belts slipping when starting because of the rotational inertia, and if, for some reason the motor were to seize, I'm sure the chuck will come winding off like a top.

Steve

I do run a 9" buck adjust-true six jaw chuck on my 10L. Big but it works fine.
You can do small stuff in a big chuck but you can't do large stuff in a small chuck.

Just today, the used 8" Buck I just bought was delivered for my 11" lathe
Currently wearing a 6" , 6-jaw- I was amazed at the weight difference though i shouldnt have been; math sez it'll weigh nearly 80% more.

It is massive in comparison to the 6", but the spindle can handle it.
On larger machines they often spin the biggest chuck they can handle because as was said, when you need it...and changing chucks requires a hoist.

I am not sure anyone really answered your question, so I will. The 8" chuck will not weight too much for your lathe to handle.

Thanks for your input Gary. Now that I've taken the chuck home and have it near the machine it's not as out of proportion as I visualized when I was just looking at the chuck by itself at work on a shelf.