Acceptable two-collar test taper?
Close
Login to Your Account
Results 1 to 2 of 2
  1. #1
    Join Date
    Sep 2015
    Country
    UNITED STATES
    State/Province
    Florida
    Posts
    578
    Post Thanks / Like
    Likes (Given)
    4
    Likes (Received)
    83

    Default Acceptable two-collar test taper?

    Finally got the lathe leveled up (and tooled), chucked up a 1-3/4" chunk of aluminum (8" out from the chuck)and I'm getting about half a thou difference over that 8".

    Wondering whether I should mess with it (and risk making it worse...), Sheldon on full cabinet stand and it was an "interesting" experience getting it to about dead nuts on the level at the ends of the bed.

    I don't do any long turning typically, but I am curious about what "typical" tolerances were required when these 50's vintage machines were rolled out of the factory?

    Pleasantly surprised that the spindle taper showed barely a flicker on the tenths indicator, so all good there

  2. Likes michiganbuck liked this post
  3. #2
    Join Date
    Jun 2012
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    9,957
    Post Thanks / Like
    Likes (Given)
    3358
    Likes (Received)
    3567

    Default

    Taking a cut? The \ out of chuck 8" is very good but includes chuck error and aluminum bar stock is not very straight. Turning .0005 out 8" is good. You can turn a piece/stub the same diameter as your quill then indicate that, and to your quill at a number of places along the bed. Even that is a poor check because your indicator can rise and fall with bed wear. You can turn that stub and feel your tool bit and look at your dial numbers feeling the quill , yes tab of tape or shim so not marring the quill if you wish..Some times with an older lathe the part length tell of a little bit of needed adjustment.
    QT;[Wondering whether I should mess with it] *Not with that kind of check..at another length it may be different. .

    Running a part one can micrometer a part head and tail end..then feel a tool bit at both places to see/adjust the difference. So setting the taper .001 or so with not taking the long time needed to feed a cut for the part length.. Yes with checking a centered part to see the center is good/center. Often I used my tool holder not the tool bit for the touch,and a slip of paper as a feeler shim. Yes nothing wrong with using a indicator if yo can do that quick.

    QT;[what "typical" tolerances were required when these 50's vintage machines were rolled out of the factory?] Some shops needed tenths..and if the tool bit only did .001/.oo2 you used a piece of abrasive cloth and made the print.


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
  •