[Newbie] Need Help Selecting New Chuck for South Bend 10

[karlsangree]

The '42 South Bend Heavy 10 toolroom lathe I just purchased came with a much abused and badly worn 5" 3-jaw chuck. There are a couple of almost invisible hairline cracks in the body and it looks as though the chuck was threaded on to a big piece of pipe and used as a hammer. I haven't checked the jaws but wouldn't be surprised if they were badly tapered. The chuck functions... but barely.

Four Questions:

1. As a newbie, what do I look for in a replacement? I have seen them go from $100 to $650. Given my status as a total noob, I don't think I'll get $650 of precision out of a $650 chuck, but is $100 too cheap? Would a $650 chuck really be more than 5X the precision/quality than a $100 chuck?
2. Are the backing plate bolt hole patterns standard or should I plan on machining a backing plate (which right now is a little above my pay grade). I would really like to avail myself of a "plug and play" option.
3. Can I reuse the current backing plate or just get a new one with the chuck?
4. 5" or 6" - The 3-jaw is 5", but my 4-jaw is 6"

As you can see, I have no idea what I'm doing here and can use all the help I can get. Thanks!

EDIT: Side question... the machined piece that mounts the chuck to the lathe, I've seen the called mounting plates, backing plates, and adapter plates. Is one preferred? Are they actually referring to the same thing?

 

[mmcmdl]

Does that SB have a straight thread mount ? Maybe a 2" ? thread ?

 

[karlsangree]

Does that SB have a straight thread mount ? Maybe a 2" ? thread ?

Threaded mount. I believe it's 2.250 x 8

Also, I forgot to mention that the 3-jaw chuck is 5". The lathe also came with a cheap 6" 4-jaw that I was able to rebuild and that works fine now.

Also also, 5" or 6" on the replacement 3-jaw?

 

[mmcmdl]

Gimme a minute .

 

[mmcmdl]

1 7/8"-8 ?

 

[mmcmdl]

Those SBs sure had a bunch of different spindle options . I do have a 1 7/8-8 with a couple chucks which won't do much for you , but I tried .

 

[karlsangree]

1 7/8"-8 ?

2.250 x 8

 

[karlsangree]

Those SBs sure had a bunch of different spindle options . I do have a 1 7/8-8 with a couple chucks which won't do much for you , but I tried .

Wow! Thanks for trying. I really appreciate it.

This is the 8187AN Toolroom model with the 5C collet adapter which is why (I'm guessing) it is equipped with the larger spindle bore.

 

[mmcmdl]

Wow! Thanks for trying. I really appreciate it.

I tried . These came off of a Heavy 10 but it may have been older or newer . I can't use them as I need L00s . I have a 6" Bison 4 jaw scroll chuck and a 6" 3 jaw

 

[Nogoingback]

One question you might ask yourself is what your expectations for the chuck are. 3 jaw chucks are
not known for precision, but if that's what you want, you'll need a set-tru chuck to get the runout to
a reasonable number. If you have the time you could try to find a Pratt or Bison in good shape on eBay
for that. If you want the chuck for first ops only, you could look into a Shars. Some folks around here are happy
with them. If you really want to do precise work, the four jaw is your friend.