Bar grinding
Close
Login to Your Account
Results 1 to 12 of 12

Thread: Bar grinding

  1. #1
    Join Date
    Aug 2016
    Country
    UNITED STATES
    State/Province
    Ohio
    Posts
    24
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    0

    Default Bar grinding

    Hey. Its been a while. Got a job about a month ago centerless grinding steel bars not sure what kind of steel. 1 1/2 to 4 bars 12-24 ft. Having lots of problems. No one to really discuss them with right now. One guy quit, one hurt his shoulder. 24 x 20 wheels. Having a problem with a section in the bars Same spot. Where as I told a coworker. It feels like Im making Allen keys. Center height ok at least according to the formula I was given. Bronze work rest. 45 degree angle. Usually occurs as the part leaves the support heading into the grinder. Vibrates terribly. Not sure why. Bar and work rest seem parallel. Has happened on more than one job. Like the job and hope I can figure this out so I can keep it. Any suggestions? More info needed? Reg wheel 32 rpm. .012 taken off per pass. Crazy. Only about a 6-10 in section bad. Bar grinding much different than bolts. Lol

  2. #2
    Join Date
    Apr 2013
    Location
    Damascus, MD
    Posts
    1,178
    Post Thanks / Like
    Likes (Given)
    3337
    Likes (Received)
    657

    Default

    Caveat: I do not have direct experience with centerless grinding. But your problem sounds to me that the support needs adjusting. Depending how close or how far from the wheel/other supports is, you need to compensate for the natural flection of the bar due to gravity, so that the bar doesn't drop when leaving the support.

    Paolo

  3. #3
    Join Date
    Dec 2006
    Location
    Ohio
    Posts
    44
    Post Thanks / Like
    Likes (Given)
    29
    Likes (Received)
    1

    Default

    Bars must be very straight. Sounds like maybe bearings gone on reg wheel. edit: check the drive system on reg wheel, belt was bad about 8 years ago and had us scratching our heads.

  4. #4
    Join Date
    Dec 2016
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    67
    Post Thanks / Like
    Likes (Given)
    48
    Likes (Received)
    14

    Default

    If the bars are bent or not supported correctly and a section of the bar travels up in relationship to the GW and RW the bar will bounce between the wheels.
    Based on the information you provided it sounds like something is increasing the work piece height. What tangent angle are you set up at?
    Tangent angle is the angle from the RW to the centerline of the work piece added to the angle from the GW to the centerline of the work piece.
    You should be adjusting the tangent angle for different diameter work pieces.

  5. #5
    Join Date
    Aug 2016
    Country
    UNITED STATES
    State/Province
    Ohio
    Posts
    24
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    0

    Default

    Quote Originally Posted by Sicardski View Post
    If the bars are bent or not supported correctly and a section of the bar travels up in relationship to the GW and RW the bar will bounce between the wheels.
    Based on the information you provided it sounds like something is increasing the work piece height. What tangent angle are you set up at?
    Tangent angle is the angle from the RW to the centerline of the work piece added to the angle from the GW to the centerline of the work piece.
    You should be adjusting the tangent angle for different diameter work pieces.
    Seems like the blade may be going downhill but not 100% sure. Really helped grabbing end of bar and pulling slightly away from grinding wheel. Not the best or safest solution but seems to work.

  6. #6
    Join Date
    Aug 2005
    Location
    Tucson AZ
    Posts
    6,087
    Post Thanks / Like
    Likes (Given)
    8474
    Likes (Received)
    2800

    Default

    Bert, can give us a pic or drawing of the set up? Are you using a long bar attachment? 4" bars seems like slant bed territory.

  7. #7
    Join Date
    Aug 2016
    Country
    UNITED STATES
    State/Province
    Ohio
    Posts
    24
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    0

    Default

    Trying to figure out how to add a picture but it seems no matter what Im doing I have to be slanted down hill entering the grinder in order to be even against the work blade. Blade not sitting on any thing. Cleaned pocket out real good.

  8. #8
    Join Date
    Aug 2016
    Country
    UNITED STATES
    State/Province
    Ohio
    Posts
    24
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    0

    Default

    a612f9f2-40c5-480a-b374-31e3296d3acd.jpg
    Picture of support entering grinder. When it ran decent.

  9. #9
    Join Date
    Aug 2016
    Country
    UNITED STATES
    State/Province
    Ohio
    Posts
    24
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    0

    Default

    Anyone ever grind below center?

  10. #10
    Join Date
    Aug 2005
    Location
    Tucson AZ
    Posts
    6,087
    Post Thanks / Like
    Likes (Given)
    8474
    Likes (Received)
    2800

    Default

    No, but with a 4 " bar you likely don't have room to. Are you depending on the wheel to pull the bar in or does it get some help until the wheel has a grip?
    When you say "blade not sitting on anything", what does that mean? You say that you have to have the bar "slanted down hill to be even against the work blade". Does this mean your bar feed is not at the right height to enter the wheels at the proper height?
    Last edited by tdmidget; 09-14-2018 at 11:18 AM.

  11. #11
    Join Date
    Aug 2016
    Country
    UNITED STATES
    State/Province
    Ohio
    Posts
    24
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    0

    Default

    I put the bars in the fixture and roll them until they start to grind. It seems as if when I am even(level) on the entry rolls. And flat on the blade(first 6 inches) entering the wheels, if I push the bar through, on the exit side I am .050 to .085 off the blade. And to get it even on the blade or work rest. Not sure what is the correct term, I have to lift the front of the bar enough so that it looks like its slanted down hill.

    I remember when I first got on here my old company wouldnt let me dress the wheels, here I cannot I honestly do not know what Im dressing the wheel with. I asked if they rotate their diamond. They said nah. Well look at it next time we change the wheels. Which could be months!! Tried to take a picture of it but due to dirt and the odd shape of the thing I couldnt tell what the heck I was looking at!!

  12. #12
    Join Date
    Aug 2005
    Location
    Tucson AZ
    Posts
    6,087
    Post Thanks / Like
    Likes (Given)
    8474
    Likes (Received)
    2800

    Default

    It sounds as though the bar attachment is too low. The bar should feed smoothly onto the guides and into the wheels. This means adjust every stand on the bar attachment or feeder as some call it , to get the correct height. It sounds as though your wheels are having to pull the bar down on to the guides. Until that pull down of the wheels get it flat on the rest it has no choice but to chatter. I think the height of the bar attachment is your problem.


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
  •  
2