5C Set-Tru Collet Chuck Repeatability
Close
Login to Your Account
Results 1 to 10 of 10
  1. #1
    Join Date
    Dec 2008
    Location
    Cincinnati, Ohio
    Posts
    87
    Post Thanks / Like
    Likes (Given)
    17
    Likes (Received)
    21

    Default 5C Set-Tru Collet Chuck Repeatability

    Greetings,

    I recently purchased a new Bison 5" 5C Set-Tru collet chuck with an L00 backplate. Took a skim-cut on the face of the back plate to eliminate about .001 of axial runout when mounted on my spindle. The chuck was mounted and zeroed for < a tenth of run out on the inner 5C taper. Mounted a 3/4" test bar in a collet with less than 2 tenths TIR 1" from the nose.

    Now my question, after unmounting and remounting the chuck on the spindle I typically measure about .0007 of runout on the 5C taper, worst case about a thou and 2 thou TIR on the test bar. This is good enough for about 80% of the work I do, but not when I need to flip and re-chuck a part.

    Is this repeatability typical for this setup? Am I going to need to redial this in every time I mount the chuck and have one of these re-chuck jobs or, is there a possible issue with the taper mount on the spindle or chuck? TIR on my spindle is < a tenth, no burrs, super clean.


    Ted

  2. #2
    Join Date
    Dec 2015
    Country
    UNITED STATES
    State/Province
    Connecticut
    Posts
    755
    Post Thanks / Like
    Likes (Given)
    22
    Likes (Received)
    230

    Default

    Is your before and after taken with the test bar still in the chuck? If the lathe spindle and the chuck taper are both good, I would think it should repeat better than a tenth, just removing and remounting the chuck. You might want to isolate the potential problem into chuck/spindle and chuck/collet


    Sent from my iPhone using Tapatalk Pro

  3. #3
    Join Date
    Dec 2008
    Location
    Cincinnati, Ohio
    Posts
    87
    Post Thanks / Like
    Likes (Given)
    17
    Likes (Received)
    21

    Default

    Quote Originally Posted by ripperj View Post
    Is your before and after taken with the test bar still in the chuck?
    The before and after on the test bar is 2 tenths before and 1 to 2 thou after, 1 inch from the nose. The before and after on the 5C taper in the nose of the chuck is < 1 tenth before and 5 tenths up to a thou after removing and remounting the chuck on the spindle. I am going to dismount and mount it a few more times to get additional readings. will post results...


    If this is the best it repeats I am going to have to dial it in when needed, I don't think I will ever be able to do it as quick as a 4 jaw, have to loosen 3 cap screws locking it to the back plate and then the 4 Set-Tru screws which on the Bison are not spaced 90 degrees each, not sure I understand why they are spaced the way they are.

    Maybe I am just being a whiner, thought it would be a bit easier than this...

    -Ted

  4. #4
    Join Date
    Feb 2005
    Location
    Akron, Ohio
    Posts
    746
    Post Thanks / Like
    Likes (Given)
    306
    Likes (Received)
    107

    Default

    Have that same collet chuck. I just reset as needed. DO NOT loosen the from mounting bolts and you will be fine. It's not necessary, the adjusting screws will move the chuck body.

    Hope this helps !

  5. #5
    Join Date
    Aug 2005
    Location
    Tucson AZ
    Posts
    6,261
    Post Thanks / Like
    Likes (Given)
    9278
    Likes (Received)
    2931

    Default

    What makes you think it should repeat like that when you mount/demount the chuck? It is supposed to repeat from part to part in the same collet.

  6. Likes Limy Sami liked this post
  7. #6
    Join Date
    Dec 2008
    Location
    Cincinnati, Ohio
    Posts
    87
    Post Thanks / Like
    Likes (Given)
    17
    Likes (Received)
    21

    Default

    Quote Originally Posted by tdmidget View Post
    What makes you think it should repeat like that when you mount/demount the chuck? It is supposed to repeat from part to part in the same collet.
    .002 TIR isn't much better than the 3 jaw, just seemed like it should be better. Once trued in, re-chucking with the same collet is fine ~0.0002 with an import collet. It is a new set up for me, so I did not know what I should expect...

  8. #7
    Join Date
    Feb 2001
    Location
    Redwood City, CA USA
    Posts
    4,930
    Post Thanks / Like
    Likes (Given)
    171
    Likes (Received)
    871

    Default 5C Set-Tru Collet Chuck Repeatability

    It seems like there is a problem with the seating of the L00 male and female tapers. Does the runout change if you tonk the side of the chuck nose with a dead-blow hammer? I suggest you take off the key, blue up the female taper, and see how it is seating on the make taper. Taking off the key lets you apply a little twist and see the seating better. A L00 taper should repeat dead nuts, but if the angles are mismatched or there are dings and burrs, the assembly can cock one way or the other ever so slightly each time you mount it. Also make sure the threaded L00 ring is not dinged up and pulling one side more than another.


    Sent from my iPhone using Tapatalk

  9. Likes henrya liked this post
  10. #8
    Join Date
    Oct 2010
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    5,009
    Post Thanks / Like
    Likes (Given)
    4170
    Likes (Received)
    1809

    Default

    Quote Originally Posted by wr4t View Post
    Once trued in, re-chucking with the same collet is fine ~0.0002 with an import collet.
    This is good, and what you'd expect.

  11. #9
    Join Date
    Dec 2008
    Location
    Cincinnati, Ohio
    Posts
    87
    Post Thanks / Like
    Likes (Given)
    17
    Likes (Received)
    21

    Default Success!

    Quote Originally Posted by rklopp View Post
    Also make sure the threaded L00 ring is not dinged up and pulling one side more than another.
    Thank you for the tip, the threads on the L00 back plate still had burrs on them. The clamping pressure on the taper from the lock ring must have been uneven. Filed the burrs down and cleaned up the rough looking threads. Repeatability much improved over 5 mounts dismounts:

    1. nil
    2. < 0.0003
    3. 0.0001
    4. 0.0001
    5. 0.0001


    Torqueing the lock ring down every 90 degrees with the spanner was necessary to get better than 0.0005, and the tip about keeping the bolts holding the chuck to the back plate tight when adjusting the Set-Tru cap screws greatly simplifies zeroing in the chuck.


    Appreciate the helpful tips,


    Ted WR4T

  12. #10
    Join Date
    Feb 2001
    Location
    Redwood City, CA USA
    Posts
    4,930
    Post Thanks / Like
    Likes (Given)
    171
    Likes (Received)
    871

    Default

    Those readings are about as good as you can expect for the machine and chuck you've got. Glad you solved the issue.


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
  •