Small part in big lathe
Close
Login to Your Account
Page 1 of 2 12 LastLast
Results 1 to 20 of 28
  1. #1
    Join Date
    Mar 2007
    Location
    Salem,Ohio
    Posts
    551
    Post Thanks / Like
    Likes (Given)
    17
    Likes (Received)
    311

    Default Small part in big lathe

    We needed a new nut for the elevator screw in one of our g&l boring mills. They wanted $3,500 for a new one so i am making one. These lead screws have a lead of .375 and this is the only lathe we have that will cut that lead. This is a 50" lathe makjng a 5" dia. nut.
    Attached Thumbnails Attached Thumbnails 20191203_074720.jpg  

  2. #2
    Join Date
    Jul 2004
    Location
    Houston, TX USA
    Posts
    29,744
    Post Thanks / Like

    Default

    NN Monarch saves the day

  3. #3
    Join Date
    Nov 2014
    Country
    UNITED STATES
    State/Province
    Florida
    Posts
    3,722
    Post Thanks / Like
    Likes (Given)
    1535
    Likes (Received)
    1761

    Default

    Quote Originally Posted by cuttergrinder View Post
    We needed a new nut for the elevator screw in one of our g&l boring mills. They wanted $3,500 for a new one so i am making one. These lead screws have a lead of .375 and this is the only lathe we have that will cut that lead. This is a 50" lathe makjng a 5" dia. nut.
    That is a big lathe, but don't you have a smaller chuck?!?!

  4. Likes Hardplates liked this post
  5. #4
    Join Date
    Aug 2004
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    2,285
    Post Thanks / Like
    Likes (Given)
    174
    Likes (Received)
    830

    Default

    I would be concerned about rigidity. You might need to put a follow rest on that thing.

  6. Likes lucky7, TDegenhart, rcoope, lumley32 liked this post
  7. #5
    Join Date
    Mar 2007
    Location
    Salem,Ohio
    Posts
    551
    Post Thanks / Like
    Likes (Given)
    17
    Likes (Received)
    311

    Default

    We do have a smaller chuck but we never put a smaller one on this lathe. This big one works just fine.

  8. #6
    Join Date
    Mar 2007
    Location
    Salem,Ohio
    Posts
    551
    Post Thanks / Like
    Likes (Given)
    17
    Likes (Received)
    311

    Default

    Its plenty rigid. I machine bushings like that that are 24" long

  9. #7
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    7,493
    Post Thanks / Like
    Likes (Given)
    1762
    Likes (Received)
    5213

    Default

    To heck with the nut, how big is that QCTP? It's got to be around 8" tall at the block or something close to that!

    If it's an Aloris, what's the letter size?

  10. #8
    Join Date
    Mar 2005
    Location
    Northwest Indiana
    Posts
    4,058
    Post Thanks / Like
    Likes (Given)
    710
    Likes (Received)
    769

    Default

    Maybe an Aloris E? Nice to have a QCTP. All of the big lathes in the places I worked had bar clamps on the tool posts! Exact opposite of quick change.

    You know there's a place in WI that specializes in making brass/bronze nuts for machines... forget the name of the place but we got all our G&L table and head nuts there... they were more like $1k, much more palatable. And they did a good job.

    There were a few times that we took the screws out and re-cut the threads so that the pitch was more uniform rather than heavily worn in the middle... for those we made our own nuts.

  11. Likes Bobnotthecat liked this post
  12. #9
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    7,493
    Post Thanks / Like
    Likes (Given)
    1762
    Likes (Received)
    5213

    Default

    Yeah, I guess the block is around 5" high if one accounts for the distance from the nut (which is presumably 5" OD on the exposed cylinder).

  13. #10
    Join Date
    Mar 2007
    Location
    Salem,Ohio
    Posts
    551
    Post Thanks / Like
    Likes (Given)
    17
    Likes (Received)
    311

    Default

    The toolpost is an aloris but the tag is missing. The block is about 6" square by 5" tall.

  14. #11
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    7,493
    Post Thanks / Like
    Likes (Given)
    1762
    Likes (Received)
    5213

    Default

    Quote Originally Posted by cuttergrinder View Post
    The toolpost is an aloris but the tag is missing. The block is about 6" square by 5" tall.
    That would make it an "E" series: https://www.aloris.com/aloris_cat/31e970.pdf

    I thought it was bigger initially, as I thought the 5" nut was the thread, not the body OD.

  15. #12
    Join Date
    Aug 2015
    Country
    UNITED STATES
    State/Province
    Illinois
    Posts
    1,387
    Post Thanks / Like
    Likes (Given)
    992
    Likes (Received)
    594

    Default

    You definitely want to turn that part around in the chuck for a more secure grip. A .375 lead will mean substantial cutting forces. You will probably need a special threading bar for that pitch & diameter combination. You may not have enough room to back out the tool and crank it out with the carriage. You will probably have to back the tool off a little and wind the tool out by reversing the spindle. I had a similar issue with a 3/4-4 Acme.

  16. Likes eKretz liked this post
  17. #13
    Join Date
    Jul 2009
    Location
    S.W. PA
    Posts
    236
    Post Thanks / Like
    Likes (Given)
    62
    Likes (Received)
    57

    Default

    Yeah.....About 30 years ago I had the misfortune of working at a small weld shop for a very difficult owner. The Wotan horizontal boring mill pulled the threads out of the table nut. I then told him where he could buy the bronze stock to make a new one. I was not expecting what happened next. He puked onto me the most horrible string of profanity and vulgarisms I'd ever heard, to the effect that he wasn't going to pay me to machine a new nut when he could get the parts from Wotan. After a few phone calls he slinked back and told me that Wotan wanted $5000.00 for the new nut and that it had to be shipped from Germany. The bronze was then ordered and overnighted. If I remember correctly it was 5 TPI on a 50 millimeter shaft.

    I quit that place right quickly thereafter.

    Bob....not the cat.
    Last edited by Bobnotthecat; 12-03-2019 at 11:56 AM.

  18. #14
    Join Date
    Jun 2019
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    278
    Post Thanks / Like
    Likes (Given)
    85
    Likes (Received)
    237

    Default

    Quote Originally Posted by Bobnotthecat View Post
    Yeah.....About 30 years ago I had the misfortune of working at a small weld shop for a very difficult owner. The Wotan horizontal boring mill pulled the threads out of the table nut. I then told him where he could buy the bronze stock to make a new one. I was not expecting what happened next. He puked onto me the most horrible string of profanity and vulgarisms I'd ever heard, to the effect that he wasn't going to pay me to machine a new nut when he could get the parts from Wotan. After a few phone calls he slinked back and told me that Wotan wanted $5000.00 for the new nut and that it had to be shipped from Germany. The bronze was then ordered and overnighted. If I remember correctly it was 5 TPI on a 50 millimeter shaft.

    I quit that place right quickly thereafter.

    Bob....not the at.
    Christ. I know that you don't always get the option to leave a job right off with out another lined up, but that definitely seems a case to tell the guy to F-off and make it himself after that.

  19. Likes Bobnotthecat, M.B. Naegle liked this post
  20. #15
    Join Date
    Jan 2005
    Location
    Houston
    Posts
    5,589
    Post Thanks / Like
    Likes (Given)
    492
    Likes (Received)
    2408

    Default

    Neat, but I'd be more impressed to see you make a 50" nut on a 5" lathe...!

  21. Likes DrHook, Limy Sami, ronf, Ron Hofer, Hightemp and 1 others liked this post
  22. #16
    Join Date
    Mar 2007
    Location
    Salem,Ohio
    Posts
    551
    Post Thanks / Like
    Likes (Given)
    17
    Likes (Received)
    311

    Default

    Quote Originally Posted by Illinoyance View Post
    You definitely want to turn that part around in the chuck for a more secure grip. A .375 lead will mean substantial cutting forces. You will probably need a special threading bar for that pitch & diameter combination. You may not have enough room to back out the tool and crank it out with the carriage. You will probably have to back the tool off a little and wind the tool out by reversing the spindle. I had a similar issue with a 3/4-4 Acme.
    Its all threaded. No poroblem with hanging out or with the bar. Just used an 1 1/4 bar and a 3/8 high soeed tool.

  23. #17
    Join Date
    Mar 2007
    Location
    Salem,Ohio
    Posts
    551
    Post Thanks / Like
    Likes (Given)
    17
    Likes (Received)
    311

    Default

    The thread is actually 2 1/4 acme with a 3/8 pitch. The flange of the nut which is in the chuck is about 5".

  24. #18
    Join Date
    May 2019
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    362
    Post Thanks / Like
    Likes (Given)
    97
    Likes (Received)
    128

    Default

    Quote Originally Posted by Mike1974 View Post
    That is a big lathe, but don't you have a smaller chuck?!?!
    Changing the chuck is likely a larger job than the actual job itself

  25. Likes Limy Sami, LKeithR, TeachMePlease liked this post
  26. #19
    Join Date
    Nov 2014
    Country
    UNITED STATES
    State/Province
    Florida
    Posts
    3,722
    Post Thanks / Like
    Likes (Given)
    1535
    Likes (Received)
    1761

    Default

    Quote Originally Posted by cuttergrinder View Post
    We needed a new nut for the elevator screw in one of our g&l boring mills. They wanted $3,500 for a new one so i am making one. These lead screws have a lead of .375 and this is the only lathe we have that will cut that lead. This is a 50" lathe makjng a 5" dia. nut.
    That is probably true, but it seems the rpm would be very very limited with a chuck that size... maybe a wash time wise?

  27. #20
    Join Date
    Mar 2005
    Location
    Northwest Indiana
    Posts
    4,058
    Post Thanks / Like
    Likes (Given)
    710
    Likes (Received)
    769

    Default

    Quote Originally Posted by cuttergrinder View Post
    Its all threaded. No poroblem with hanging out or with the bar. Just used an 1 1/4 bar and a 3/8 high soeed tool.
    Having (hopefully) somewhat sharp chuck jaw teeth and relatively soft material helps there. I would probably have had stops bolted to the chuck face so the nut could be supported behind the flange all the same. That is just good practice.


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
  •