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Thread: Leadscrew Freeplay

  1. #16
    Join Date
    Feb 2003
    Location
    Houston, Texas
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    7,067
    Quote Originally Posted by Jay Cutright View Post
    Yessir!
    Jay, that also is of no consequence.

  2. #17
    Join Date
    Apr 2007
    Location
    Illinois
    Posts
    587
    [QUOTE=HiWall;816719]
    Quote Originally Posted by Jay Cutright View Post

    Also check to see what freeplay you might have at various points on the lead screw. Might be a bit more sloppy near the chuck as most threading may be done here
    Some things you and Chet mentioned here got me out in the shop looking this machine over again instead of going by what I remember.
    The measurement you mentioned checking is what I would consider the clearance the half nuts have on the leadscrew. I was thinking when I reassembled this machine I went through an adjustment procedure on the half nuts but I was mistaken, I did that on my big grizzly. It produces better threads with some clearance in the half nuts and the leadscrew, I learned something this week.
    Now I'm back on my 10L, I have .007 play at the saddle and I know .001 of that is the leadscrew itself so have some clearance in the half nuts and it is consistent throughout the length of the leadscrew.
    The leadscrew does not bind so I'm leaving it alone.

  3. #18
    Join Date
    Aug 2007
    Location
    Kansas
    Posts
    221
    Jay thanks for the kind reply makes a lot scene. Having the lead screw adjusted at the gear box to tight could create a bend in the lead screw.
    Glad you found what ever it was and got your Heavy 10 fixed to your liking.

    Chet

  4. #19
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    Feb 2003
    Location
    Houston, Texas
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    7,067
    This is a little off the topic, but I thought I would mention it for enthusiast to be aware of.

    On lathes such as the South Bend, you have a plain bearing thrust That controls the end play in the spindle.

    If you have noticed that when threading off center, the tool seems to wander from one side of the thread to the other, (whether internal or external), your spindle thrust is probably too loose. It needs to be just snug enough so that it does not build heat, but not so loose as to allow the spindle to drift back and forth in it's bearings.

    It's easy to adjust with the nuts at the rear of the spindle.

  5. #20
    Join Date
    Feb 2006
    Location
    California...unfortunately
    Posts
    593
    Jay,

    I think you have likely figger'd this out, but I doubt that one thou in lead screw play is causing your threading issues. I'd be inclined to look at such things as tool rigidity, gib tightness, the compound being cranked towards the work or locked down, etc.

    Justin

  6. #21
    Join Date
    Feb 2003
    Location
    Tennessee
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    6,391
    Quote Originally Posted by Zebra13 View Post
    Jay,

    I think you have likely figger'd this out, but I doubt that one thou in lead screw play is causing your threading issues. I'd be inclined to look at such things as tool rigidity, gib tightness, the compound being cranked towards the work or locked down, etc.

    Justin

    Probably 90% of thread finish issues is threading tool geometry.



    .

  7. #22
    Join Date
    Jul 2005
    Posts
    389
    Quote Originally Posted by Zebra13 View Post
    Jay,

    If I'm understanding you correctly, you have an indicator touching the end of your lead screw, and you get .001 when you push the lead screw from side to side, meaning moving it parallel with the bed of the lathe. Correct?

    Justin
    Threads are normally only cut in ONE direction.
    It does not matter as long as the lead screw comes to the same position when you start cutting each time.

    It will only affect the very first part of the thread cut as the lead screw moves.

    Far easier to remove the first half thread than try to make it perfect.

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