QCGB Gear box counter shaft won't come out
Close
Login to Your Account
Results 1 to 9 of 9
  1. #1
    Join Date
    Dec 2020
    Country
    UNITED STATES
    State/Province
    Illinois
    Posts
    2
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default QCGB Gear box counter shaft won't come out

    Greetings, This is my first post. I am grateful for all that I have learned so far.

    I am rebuilding a 16 x 54 tool room lathe I bought at auction in Ohio. I cannot get the long shaft in the gear box to come out. It will move about 1/4 inch in either direction with a 3lb hammer and a big brass drift. I thought maybe I had bent it removing the central taper pin, but I put an indicator on it and it seems fine. I fished the old felts out with a scroll saw blade but that did not help. The shaft is now very hard to turn, though it was not before I tried to drive it out. The small gear furthest toward the input side of the box will turn freely on the shaft if I tap the shaft to the center but locks to the shaft if I tap the shaft left or right. I think this a clue but I do not know what it means. The rebuild books and threads I have read say it should come out if driven toward the output side of the GB, but mine is stuck. I welcome any advice.
    Thank you.
    Karl


    img_5001.jpg

  2. #2
    Join Date
    Mar 2016
    Country
    UNITED STATES
    State/Province
    Vermont
    Posts
    21
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    8

    Default

    If you are confident there is no other part that needs removing first, I would suggest putting it on a hydraulic press. This will be higher force and probably more controlled, less damage than hammering on it. After it is out, I guess cleaning up the shaft will make it turn properly. Most auto shops will have a press if you don't. Others may correct me as I have no experience with that shaft.

  3. #3
    Join Date
    Feb 2016
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    1,873
    Post Thanks / Like
    Likes (Given)
    1283
    Likes (Received)
    705

    Default

    Dont put it in a press.

    I need to get back to you in the evening to review parts. But i think there is a key under a gear, and into shaft. You are probably driving key into an adjacent gear in one direction, and driving the same key into housing the other direction.

    I seem to recall another pin or something holding another gear, but again i need to review parts this evening.

    Is this single, or double tumbler ?

    Also post two more pics. One of each side showing outer bushing, whatever. The two outside sections where we see end of shaft.

  4. #4
    Join Date
    Feb 2011
    Location
    BFE Nevada/San Marcos Tx
    Posts
    2,900
    Post Thanks / Like
    Likes (Given)
    2973
    Likes (Received)
    1840

    Default

    Another member here did a vid tutorial on disassembling an SB, not sure if its the same as yours, he had trouble getting the shaft out of the QCGB too, see if this helps 1941 South Bend 13" Lathe Restoration - Part 8 - Single Tumbler Gear Box Disassembly - YouTube

  5. #5
    Join Date
    Jan 2014
    Location
    North Carolina
    Posts
    546
    Post Thanks / Like
    Likes (Given)
    25
    Likes (Received)
    169

    Default

    I gotta say that it scares me a little to see a hammer as large as the one in the picture as part of a discussion about a quick change gear box. More investigation is called for.

  6. #6
    Join Date
    Feb 2016
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    1,873
    Post Thanks / Like
    Likes (Given)
    1283
    Likes (Received)
    705

    Default

    Yours appears to be double tumbler. I'm a little less familiar with those. But I think some of the same principles apply.

    Parts manual from 1965:
    South Bend Lathe Works - Publication Reprints - South Bend Complete Parts Bulletin Collection 10 - 16" Lathes CE 3458 | VintageMachinery.org

    The pdf from that link:
    http://vintagemachinery.org/pubs/1617/24411.pdf

    Go to page 54 in the pdf, but I'll post a cut pic from it.

    Pretty sure the pin, part# 39 needs to come out.

    Note part numbers 48, 49, and 50, the keys. Without it in front of me, I think you need those keys lined up with the slot in the housing. If you already beat on it a bit, might of dinged the case or end of keys a little, so might be a little trickier or tighter getting out.

    There may be a trick to it, like getting shaft part way knocked through one direction, remove exposed key, go the other way, get that key. . . Not totally sure, but pretty certain you'll need to be lined up with slot in case for sure.

    71.jpg

  7. Likes JBTR liked this post
  8. #7
    Join Date
    Jan 2021
    Country
    UNITED STATES
    State/Province
    Ohio
    Posts
    184
    Post Thanks / Like

    Default

    Quote Originally Posted by dalmatiangirl61 View Post
    Another member here did a vid tutorial on disassembling an SB, not sure if its the same as yours, he had trouble getting the shaft out of the QCGB too, see if this helps 1941 South Bend 13" Lathe Restoration - Part 8 - Single Tumbler Gear Box Disassembly - YouTube
    Just to be clear, my video was less of a "How to do it" and more of a "How I did it" documentary. I make no claims that anyone, anywhere, under any circumstances, should do what I did.

  9. Likes Yan Wo, dalmatiangirl61 liked this post
  10. #8
    Join Date
    Dec 2020
    Country
    UNITED STATES
    State/Province
    Illinois
    Posts
    2
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default QC Gear box counter shaft wont come out. Solved.

    Thank you all for your helpful suggestions. I am sorry to have been so long in replying. I did finally get it apart and I found out what the clue meant. There was spalling between the first gear and the shaft, so the gear would turn on the shaft only if the scored grooves were aligned. Eventually the big hammer did the trick. I do not think I damaged the housing pushing the spalled shaft through. I might be able to salvage the shaft, but will need a new gear.

    img_5021.jpg

  11. #9
    Join Date
    Jan 2021
    Country
    UNITED STATES
    State/Province
    Ohio
    Posts
    184
    Post Thanks / Like

    Default

    If you are unable to find a new gear, bore the gear out and press in a bronze bushing. My guess is the shaft is probably what will need to be replaced. That spalling is only going to make any new gear worse. The other option would be to clean that section of the shaft, turn it down, build it up with metalizer or TIG brazing or weld, and then turn it back to size.


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
  •