Centering non-bar fed lathe stock
Close
Login to Your Account
Results 1 to 9 of 9
  1. #1
    Join Date
    Aug 2006
    Location
    california
    Posts
    279
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    28

    Default Centering non-bar fed lathe stock

    We do a fair amount of protos where the stock is larger than the chuck through hole. So have to pre-cut stock to length. And my cutoff saw does not always cut perfectly perpendicular. Are there some old school tricks to centering stock close to minimal runout in the chuck?

    I currently set the tool to the stock diameter, and use a square on the opposing/adjacent jaw. Am wondering there is a better way?

    If the cutoff saw is not cutting perpendicular in the vertical, does that mean the blade is dull, or the tension or speed is off?

    Sent from my SM-G975U using Tapatalk

  2. #2
    Join Date
    Jan 2003
    Location
    Posts
    623
    Post Thanks / Like
    Likes (Given)
    138
    Likes (Received)
    202

    Default

    I think the tool your looking for is called an indicator. Roll it around by hand and use dirty big hammer to adjust. Probably faster then using a lathe tool and squares. If you need faster method I supposed you could try and rig up some kind of v block on turret. Or something in tailstock to center it.

    All sorts of reasons why bandsaws drift off. Blades, guides etc etc. Might be worth while spending an hour or 2 on your saw. If all else fails you can shim stock on one side to trick it into cutting straight. Back when I started I had a POS saw and used a little strip of 1/16th flat bar that I would position just behind the cut to make it perpendicular. Worked great.

  3. #3
    Join Date
    Aug 2013
    Location
    Chicago, IL
    Posts
    1,287
    Post Thanks / Like
    Likes (Given)
    917
    Likes (Received)
    515

    Default

    Yeah, we tap it with a mallet and spin the chuck while indicating it. If I’m not mistaken, DoAll does free band saw check ups. Good luck!

  4. #4
    Join Date
    Mar 2011
    Country
    SWITZERLAND
    Posts
    1,153
    Post Thanks / Like
    Likes (Given)
    148
    Likes (Received)
    467

    Default

    Bell center punch

  5. #5
    Join Date
    Mar 2011
    Country
    SWITZERLAND
    Posts
    1,153
    Post Thanks / Like
    Likes (Given)
    148
    Likes (Received)
    467

    Default

    Have to correct myself, a bell center punch is worthless on a uneven face. What you can do, don’t know about weight of work, is to grip it in three-jaw chuck on spindle side without axial contact, claw jaws, and give it a rigid V support or steady rest on other side, then adjust with rest and hammer until it runs true. Now face off, turn round diameter for smooth chuck jaws, and flip. Sometimes one has to climb a hill step by step.

  6. #6
    Join Date
    Jun 2021
    Country
    UNITED KINGDOM
    Posts
    10
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    The workpiece is fitted in the hurl. It is adjusted as well as could be expected by the eye. The pole is then fitted into the imprint or focus in the workpiece at the workpiece end and onto a middle mounted in the tailstock. The DTI is set so it contacts the bar close to the workpiece.

  7. #7
    Join Date
    Oct 2010
    Location
    Dewees Texas
    Posts
    3,400
    Post Thanks / Like
    Likes (Given)
    36
    Likes (Received)
    1130

    Default

    On bars too big to fit though the spindle and cut off with a band saw I put the pieces in a vice and mill them with an end mill longer than the stock diameter. Gets the end fairly perpendicular. Any taper or deflection in the end mill introduce a little bit of error, but it always better than saw cut.

  8. Likes Trueturning liked this post
  9. #8
    Join Date
    Nov 2010
    Country
    UNITED KINGDOM
    Posts
    1,055
    Post Thanks / Like
    Likes (Given)
    207
    Likes (Received)
    252

    Default

    Quick and dirty method, bearing on the end of a bar in toolholder, like single wheel knurling tool with bearing replacing knurling wheel.

  10. #9
    Join Date
    Jun 2012
    Location
    Michigan
    Posts
    6,092
    Post Thanks / Like
    Likes (Given)
    5711
    Likes (Received)
    3893

    Default

    One trick that I used back in the day was to have soft jaws as tall as possible, but relieve the middle portion so that each jaw contacts the stock in 2 places.

  11. Likes Trueturning liked this post

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
  •