Have I over chucked my south bend 9C?
Close
Login to Your Account
Results 1 to 11 of 11
  1. #1
    Join Date
    Oct 2018
    Country
    UNITED STATES
    State/Province
    New Jersey
    Posts
    2
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default Have I over chucked my south bend 9C?

    Hi...

    I've lurked and gathered very helpful tips here for about a month since picking up a 1939 South Bend 9C. I'm brand new to machining and this is my first lathe. She spun up nicely at purchase but I have yet to set up in my studio as I'm building a sturdy butcher block style bench and acquiring some bits like a few change gears and a replacement chuck.

    The jaws on the 5" Union scroll chuck that came with the machine are quite worn but I thought no matter as I want a larger 4 jaw anyway. Having read elsewhere on this forum that 6" about right for these SB workshop lathes I picked up a very nice 6 1/2" on ebay. The point I neglected to consider is whether I should look for a light or a heavy duty chuck. The one I picked up turned out to be a heavy duty Burnerd that tops the scale at 25 lbs (about 4 times the 5" I want to replace)! With chuck mounted & spindle spun by hand everything feels buttery smooth and I would expect some extra weight could be useful to prevent problems like chatter but see my pictures... the chuck certainly looks large for the machine. I plan to face the backing plate before using any chuck I purchase (I learned that here) but my question is, would a chuck this heavy be at all useful or even safe for use on a South Bend 9?
    img_1996.jpg
    Original
    img_1997.jpg
    "New" chuck
    img_1998.jpg
    5" to 6.5"
    img_1999.jpg
    4" deep
    img_2000.jpg
    Opened to 7", ~1/2" clearance to bed

    Thanks - Mike

  2. #2
    Join Date
    Aug 2014
    Country
    AUSTRALIA
    Posts
    495
    Post Thanks / Like
    Likes (Given)
    5
    Likes (Received)
    128

    Default

    FWIW, I run an 8" 4 jaw on my 10L. It looks pretty darn big but does the job fine. I don't spin it too fast.

    I have a 6" 4 jaw as well, but the extra holding capacity on the 8" and the bore size means it is the one I normally reach for.

    Greg.

  3. #3
    Join Date
    Sep 2011
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    26,235
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    8258

    Default

    Quote Originally Posted by haus View Post
    Hi...

    I've lurked and gathered very helpful tips here for about a month since picking up a 1939 South Bend 9C. I'm brand new to machining and this is my first lathe. She spun up nicely at purchase but I have yet to set up in my studio as I'm building a sturdy butcher block style bench and acquiring some bits like a few change gears and a replacement chuck.

    The jaws on the 5" Union scroll chuck that came with the machine are quite worn but I thought no matter as I want a larger 4 jaw anyway. Having read elsewhere on this forum that 6" about right for these SB workshop lathes I picked up a very nice 6 1/2" on ebay. The point I neglected to consider is whether I should look for a light or a heavy duty chuck. The one I picked up turned out to be a heavy duty Burnerd that tops the scale at 25 lbs (about 4 times the 5" I want to replace)! With chuck mounted & spindle spun by hand everything feels buttery smooth and I would expect some extra weight could be useful to prevent problems like chatter but see my pictures... the chuck certainly looks large for the machine. I plan to face the backing plate before using any chuck I purchase (I learned that here) but my question is, would a chuck this heavy be at all useful or even safe for use on a South Bend 9?
    img_1996.jpg
    Original
    img_1997.jpg
    "New" chuck
    img_1998.jpg
    5" to 6.5"
    img_1999.jpg
    4" deep
    img_2000.jpg
    Opened to 7", ~1/2" clearance to bed

    Thanks - Mike
    Fifty, sixty years or so ago, a "premium" optioned SB shipped with a Cushman about half-way in between the two you show. Cushman about the same heft as the Pratt-Burnerd you have, but arguably stronger and better - they did fight over that - went onto spindles of Monarch 10EE and the like with a tad more heft under them and far greater power back of them.

    This one has eaten a chunk of scarce longitudinal daylight. That's about all.

    You won't run it long enough nor hard enough to much affect the bearings. Not unless you start making parts ten hours a day, every day. Which would be well short of "sane" on an SB 9 manual, anyway.

    "Safe", then, is up to you.

    That said, if the chuck is well-made?

    I'd be tempted to find a nicer lathe to put under it.... and have done.


  4. #4
    Join Date
    Mar 2012
    Location
    Geilenkirchen, Germany
    Posts
    2,307
    Post Thanks / Like
    Likes (Given)
    1394
    Likes (Received)
    1190

    Default

    No problem at all. I have run a 6" SB 4 Jaw and a 6" 3 Jaw SB chuck on my 10K since new (1980. The original SB 5" 3 jaw was no where near as good as the SB 6"......huge difference in everyway.

  5. #5
    Join Date
    Sep 2010
    Location
    Oklahoma City, OK
    Posts
    4,193
    Post Thanks / Like
    Likes (Given)
    721
    Likes (Received)
    1768

    Default

    The bearings shouldn't care, I'd be more concerned with the extra bed length and horsepower it's eating. On the other hand, it could be pushing you toward a better spot on the ways?

  6. #6
    Join Date
    Apr 2007
    Location
    Scotts Valley, CA
    Posts
    697
    Post Thanks / Like
    Likes (Given)
    42
    Likes (Received)
    64

    Default

    Quote Originally Posted by steve-l View Post
    No problem at all. I have run a 6" SB 4 Jaw and a 6" 3 Jaw SB chuck on my 10K since new (1980. The original SB 5" 3 jaw was no where near as good as the SB 6"......huge difference in everyway.
    Agree. I run both 6-1/4" and 5" 3 jaw Bison chucks on my 10k - the 6 is a heavy sucker but no problems. The 6" Bison 4 jaw I have is WAY lighter than the 3 jaw.

  7. #7
    Join Date
    Nov 2008
    Location
    Madera county california usa
    Posts
    2,401
    Post Thanks / Like
    Likes (Given)
    21
    Likes (Received)
    594

    Default

    Mass and newton...

    Flywheel effect.

    The larger rotating mass will consume a bit more power to startup so motor may complain when starting in higher speeds.

    Also note this larger rotating mass will mean less margin for error if you get something where it does not belong.

    Careful management of jaw placement is critical as you have not to much overall movement so reversing them may get old.

    ALWAYS rotate by hand to insure a jaw does not tag the ways or carriage.

    Sent from my SAMSUNG-SM-G930A using Tapatalk

  8. Likes SteveM, MetalCarnage liked this post
  9. #8
    Join Date
    Feb 2008
    Location
    newark DE USA
    Posts
    1,174
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    108

    Default

    My 9" workshop lathe came with a 7 1/2" 3jaw chuck fastened to its face plate. Im not sure what the previous owner was doing with that setup.I never used it because I got a 4" 3jaw that is very handy on that lathe. Some day I will make a plate to use that thing on my 13" Regal,it opens really wide.Point is someone had a use for that chuck on that little lathe.

  10. #9
    Join Date
    Jan 2009
    Country
    UNITED STATES
    State/Province
    Tennessee
    Posts
    1,205
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    124

    Default

    As others have said you should not have any problems using that chuck. just pay attention to what you are doing. On the other hand putting it on and removing It, Might be a challenge. You may smash a few fingers in the process. I suggest putting a good 3/4 wooden dowel well into the spindle. Leave enough on either side to use as handles. Also put a piece of wood across the bed to protect it. That thing is too heavy to take chances with.

    Stay safe and have fun.

    Joe.

  11. Likes SteveM liked this post
  12. #10
    Join Date
    Oct 2009
    Location
    Louisville, KY, USA
    Posts
    926
    Post Thanks / Like
    Likes (Given)
    213
    Likes (Received)
    204

    Default

    I occasionally use some heavy 8" chucks on my 10L, primarily for the larger through hole. It takes noticeably longer to spin up, but no other issues to date.

    With the chuck mounted on the spindle, I traced its outside diameter onto a 2x4 laid across the ways, then cut that out to create a rest that can be used to slide the chuck onto the spindle and to prevent the chuck falling on the ways or my hand during removal.

    I got the idea from someone on this forum, but it was years ago and I've forgotten who to credit.

  13. Likes Greg Menke liked this post
  14. #11
    Join Date
    Dec 2008
    Country
    UNITED STATES
    State/Province
    North Carolina
    Posts
    675
    Post Thanks / Like
    Likes (Given)
    200
    Likes (Received)
    158

    Default

    Nice looking chuck. A good brand with a reputation of well made. Just don't over extend the jaws and clip the bed or carriage and you will be golden.

    Vlad


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •