512,349 active members
2,492 visitors online
Register for free
Login
Results 1 to 12 of 12
  1. #1
    Registered
    Join Date
    Oct 2011
    Posts
    64

    Trouble keeping part straight

    Currently working on a job which is a 4.100 inch long pin with a .090 long head. The head dia. is .240 x .090 and body of pin is .120 x 4.010 long. Material is 303 SS. Probably we're having is holding the TIR of .003.
    Any pointers?

  2. #2
    Gold Member
    Join Date
    May 2004
    Posts
    4519
    Your material is probably stress relieving during machining. Are you checking TIR at each step of the cutting? Rough and finish?

  3. #3
    Registered
    Join Date
    Feb 2007
    Posts
    674
    is your spindle rpms too high , causing it to whip and bend


    I'm guessing the head is to the spindle ?

  4. #4
    Registered
    Join Date
    Oct 2008
    Posts
    108
    First of all...before we get too far with this, what is the material OD and tolerance? What type of tooling and coolant are you using? I have had this problem with materials like 17-4, but not with 303.
    www.atmswiss.com

  5. #5
    Registered
    Join Date
    Oct 2011
    Posts
    64

    Question Material od, cutting fluid we're using

    Material od is .250 with a tolerance of +/- .001. We're using Hangsterfer PC 20 cutting fluid. Cutting insert is Kenametal ccgt3250lf. Spindle running 8000 rpm at .001 upr

  6. #6
    Registered
    Join Date
    Oct 2008
    Posts
    108
    OK...first of all, I don't know anything about the PC20, but I thought that was a honing oil. We used to use their NG and it was a great oil, but they seemed to be putting gold in it because as soon as the price of gold went up, it did too (A LOT) !

    You might want to try an oil developed for Swiss machining, just a thought.

    I don't know anything about Kennemetal either, I don't use any of their tooling. We use all ISCAR, they seem to stay more on the cutting edge of the technology.

    Speeds and feeds look right to me for our tooling and oil though and the +/- .001 tolerance on the material is fine. Not sure what to tell you at this point.
    www.atmswiss.com

  7. #7
    Registered
    Join Date
    Oct 2011
    Posts
    64

    Made mistake on TIR tolerance

    Sorry guy's I had originally stated TIR tolerancing was .003. Actually I was wrong it is .002

  8. #8
    Registered
    Join Date
    Sep 2011
    Posts
    261
    We have apart kinda like this. Its a biiitch
    I have to turn .750 stock down to .2497-.0004 by 1.9" long with .0015 TIR. I tried different speeds, feeds, roughing and blending...nothing worked. we ended up boring the body and pressing in a ground .2497 shaft then had to indicate them in.

    Holding .002 over 4" is really tough in my experience... any way you could get ground stock and press the head on?

    Your issue is most likely stress in the material, but other than stress relieving the bars before you machine them I dont know how much more you can do.
    CNC Product Manager / Training Consultant

  9. #9
    Neuer Benutzer
    Join Date
    Jan 2013
    Posts
    0
    G650 support with sub spindle collet.

    I run a job that is very long. Gun drill almost 5" deep and cross drilled etc. Even though I turn the large end out where the ID work is at, and have all that weight out there I held +/-.0007 on the job last two times I ran it. Running 316 and nitronic 60 versions.

    THis option of programming is also awesome when threading a section that is longer than the landing in your guide bushing.Just rough turn it. Then sync, Then thread. Zero chatter.

  10. #10
    Gold Member
    Join Date
    May 2004
    Posts
    4519
    Run between centers yet?

  11. #11
    Registered
    Join Date
    Oct 2011
    Posts
    64

    THINK THIS WOULD HELP

    GIVE ME YOUR OPINION ON THIS.
    Attached Thumbnails Attached Thumbnails ZOOMpin.jpg  

  12. #12
    Neuer Benutzer
    Join Date
    Jan 2013
    Posts
    0

    segmenting

    You should be able to turn then sync the subspindle. I promise G650 sync turn is the best way to remain true lengths.
    Attached Thumbnails Attached Thumbnails G650 with thread, groove, gundril,l and cross drill.jpg  

Similar Threads

  1. Having trouble keeping your Parallels in place during machining
    By HelicopterJohn in forum General MetalWork Discussion
    Replies: 19
    Last Post: 03-15-2019, 03:21 PM
  2. Keeping CNC On Good or Bad
    By Cartierusm in forum DIY CNC Router Table Machines
    Replies: 10
    Last Post: 07-21-2008, 08:24 AM
  3. having trouble finding this part
    By david90 in forum DIY CNC Router Table Machines
    Replies: 6
    Last Post: 12-13-2007, 12:32 PM
  4. Keeping Men On Target
    By WallCrawler in forum Community Club House
    Replies: 2
    Last Post: 05-22-2004, 03:37 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •