1911 LeBlond thread chasing dial gear question - Page 2
Close
Login to Your Account
Page 2 of 2 FirstFirst 12
Results 21 to 31 of 31
  1. #21
    Join Date
    Jan 2005
    Location
    Victoria, Texas, USA
    Posts
    4,887
    Post Thanks / Like
    Likes (Given)
    3608
    Likes (Received)
    1397

    Default

    Go buy the gear I mentioned in post 17. It is a 3-D printed gear. I've use a non-metallic gear on the thread dial a time or two over the years. Works fine, does not have to be metal or bronze. My old Lodge & Shipley lathe has a non-metallic gear on the thread dial, made from Micrata.

    Like John Oder said, the 6-pitch lead screw, you have to match it up to a "circular pitch" gear which is very special. If you had a 4-pitch leadscrew, you can get a 12 diametrical pitch gear match up near perfectly an make it work, which I've been able to do in my past.

  2. Likes jarhead jim liked this post
  3. #22
    Join Date
    Jun 2001
    Location
    St Louis
    Posts
    19,655
    Post Thanks / Like
    Likes (Given)
    2519
    Likes (Received)
    3820

    Default

    Quote Originally Posted by jarhead jim View Post
    Ok, I made the teeth thinner, didn't do a bit of good. Turned the gear down to a smaller diameter next and that didn't any good either. When you put the gear up to the lead screw and walk it along, the second tooth hits the leading edge of the next tooth hard enough that it wouldn't go in without pushing the gear out. Is it possible this should be an 18 tooth gear? If so, it won't touch the lead screw when attached to the shaft of the thread chasing shaft. The teeth need to be closer, but still have an overall outside diameter of 1.5 inches. Is this possible? Maybe a 30 tooth gear? But then the math doesn't add up beings the lead screw is 6tpi with an overall outside diameter of 1.185.....

    Jim

    The number of teeth is set by the ratio needed (turns per inch of leadscrew). That is a "given".

    You effectively have a stub tooth rack, and you need a stub tooth gear to go with it.

  4. Likes jarhead jim liked this post
  5. #23
    Join Date
    Apr 2009
    Location
    Bartley,NE
    Posts
    206
    Post Thanks / Like
    Likes (Given)
    68
    Likes (Received)
    51

    Default

    Quote Originally Posted by 4GSR View Post
    Go buy the gear I mentioned in post 17. It is a 3-D printed gear. I've use a non-metallic gear on the thread dial a time or two over the years. Works fine, does not have to be metal or bronze. My old Lodge & Shipley lathe has a non-metallic gear on the thread dial, made from Micrata.

    Like John Oder said, the 6-pitch lead screw, you have to match it up to a "circular pitch" gear which is very special. If you had a 4-pitch leadscrew, you can get a 12 diametrical pitch gear match up near perfectly an make it work, which I've been able to do in my past.
    guess I 'll try it. Nothing else is working. Lol thanks,

    Jim

  6. Likes 4GSR liked this post
  7. #24
    Join Date
    Sep 2004
    Location
    south SF Bay area, California
    Posts
    2,210
    Post Thanks / Like
    Likes (Given)
    244
    Likes (Received)
    785

    Default

    As mentioned earlier, a threading dial needs only a trivial amount of torque to drive it. I suspect that the 24-tooth gear you showed in your photo would work if you reduce its thickness (width of gear, not tooth width), and perhaps reduce its diameter a bit.

    That said, I'll suggest thinning only at the perimeter of the gear, and keeping the hub at its stock thickness.

  8. Likes jarhead jim liked this post
  9. #25
    Join Date
    Jun 2001
    Location
    St Louis
    Posts
    19,655
    Post Thanks / Like
    Likes (Given)
    2519
    Likes (Received)
    3820

    Default

    Just to put a little visual help with this, here is a regulation SB thread dial for an 8 TPI leadscrew. Take a good look at the tooth form, and it is really not much like most gear teeth.

    This is a 32 tooth (so a "4 inch"dial) gear. The gear appears to be one of the stub tooth types. I have no idea just what it would be described as.


  10. Likes Jim Christie, jarhead jim liked this post
  11. #26
    Join Date
    Apr 2009
    Location
    Bartley,NE
    Posts
    206
    Post Thanks / Like
    Likes (Given)
    68
    Likes (Received)
    51

    Default

    Thanks fellas, I'm starting to figure out what you're saying.
    Jim

  12. #27
    Join Date
    Mar 2007
    Location
    L'Orignal, Ontario Canada
    Posts
    2,446
    Post Thanks / Like
    Likes (Given)
    2710
    Likes (Received)
    1103

    Default

    I have a 13 x 40 Kiloskar Western lathe made in India from the mid 1970s .
    It has a6TPI lead screw with a threading dial like the South Bend that swings into engagement with the lead screw
    It isn't a true worm gear ,the 24 gear teeth are somewhat angled to the helix of the lead screw and the pitch appears to finer than 16 DP and coarser than 20DP So perhaps closer to 18 but I don't have an 18 DP gear pitch gauge .

    The OD. is about 1.384" that may be too small to fit for a fixed distance .24+2 = 26/1.384= 18.786127 DP
    I'm wondering if your gear was larger like 30 or 36 teeth and was a something like a segment of a worm gear running above the centre of the lead screw something like shown in the sketch?
    Also my lead screw is only 1 inch in diameter so yours being larger could also affect the fit of the teeth as the mesh with the 6 TPI. lead screw.
    While not true to the original design it might be easier to forget making the gear and just buy a used or 3 D printed gear and or threading dial assembly for a South Bend and mount it on what ever side of the carriage it fits best as long as the South Bend lead screw is of a similar diameter.

    Jim
    Attached Thumbnails Attached Thumbnails img_1493.jpg   img_1494.jpg   img_1491.jpg   img_1492.jpg   img_1496.jpg  


  13. #28
    Join Date
    Apr 2009
    Location
    Bartley,NE
    Posts
    206
    Post Thanks / Like
    Likes (Given)
    68
    Likes (Received)
    51

    Default

    Quote Originally Posted by Jim Christie View Post
    I have a 13 x 40 Kiloskar Western lathe made in India from the mid 1970s .
    It has a6TPI lead screw with a threading dial like the South Bend that swings into engagement with the lead screw
    It isn't a true worm gear ,the 24 gear teeth are somewhat angled to the helix of the lead screw and the pitch appears to finer than 16 DP and coarser than 20DP So perhaps closer to 18 but I don't have an 18 DP gear pitch gauge .

    The OD. is about 1.384" that may be too small to fit for a fixed distance .24+2 = 26/1.384= 18.786127 DP
    I'm wondering if your gear was larger like 30 or 36 teeth and was a something like a segment of a worm gear running above the centre of the lead screw something like shown in the sketch?
    Also my lead screw is only 1 inch in diameter so yours being larger could also affect the fit of the teeth as the mesh with the 6 TPI. lead screw.
    While not true to the original design it might be easier to forget making the gear and just buy a used or 3 D printed gear and or threading dial assembly for a South Bend and mount it on what ever side of the carriage it fits best as long as the South Bend lead screw is of a similar diameter.

    Jim
    Yup, that's what 4GSR suggested and I put an order in for. It's a plastic gear but I intend on duplicating it into a steel one. And it's 18dp like you suggested I believe. My biggest problem is I can't find ANYTHING on this particular thread chaser. No picture, diagram, nothing. So going completely on suggestions and gut thoughts. I did join a LeBlond lathe club on Facebook and have a couple guys looking at their 1911 lathes.

    Thanks! Jim

  14. Likes Jim Christie liked this post
  15. #29
    Join Date
    Apr 2009
    Location
    Bartley,NE
    Posts
    206
    Post Thanks / Like
    Likes (Given)
    68
    Likes (Received)
    51

    Default

    I took 4GSR's advice and bought a plastic 18 dp 24 tooth gear off of ebay. It fit perfectly with my lead screw. I then proceeded to spend the next 4 hours making an identical one out of steel but with a 9/16" bore. I used my Putnam #2 horizontal mill with the dividing head set at a 4 degree angle to the right, img_3099.jpgimg_3102.jpgimg_3102.jpgimg_3106.jpgimg_3108.jpgmatching the angle of the plastic gear, hoping this was what you needed to do. I had made a straight tooth spur gear on this machine before and figured this was what you needed to do. I put the set screw on the bottom, rather than the top simply because it was easier to get to. I made a brass dial for the top with a polished .010 shim since the dial sits on top of the lath and pretty much just rotates there whenever the lathe is running. It works perfect! Thanks all for the help and advice on this project as this brings me just one step from having the entire original lathe.

  16. Likes Maltesehunter, Jim Christie, 4GSR liked this post
  17. #30
    Join Date
    Jul 2004
    Location
    Houston, TX USA
    Posts
    32,460
    Post Thanks / Like

    Default

    R. K. LeBlond is smiling down.

  18. Likes jarhead jim, Jim Christie liked this post
  19. #31
    Join Date
    Apr 2009
    Location
    Bartley,NE
    Posts
    206
    Post Thanks / Like
    Likes (Given)
    68
    Likes (Received)
    51

    Default

    Quote Originally Posted by johnoder View Post
    R. K. LeBlond is smiling down.
    Thanks again for your help. You are always on top of things when I have questions. I really appreciate it.

    Jim


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
  •