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Balancing Grinding Wheels

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  • #61
    Originally posted by JoeLee View Post
    I also have some 3 1/2" and 4" cup wheels that are out of balance. I don't believe there are any balancing hubs for those type wheels.
    What I may do to balance that type of wheel is put a dab of epoxy in side the cup on the heavy side to compensate.

    JL...............
    Put the epoxy on the light side.
    North Central Arkansas

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    • #62
      Yes, my typo............

      JL...............

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      • #63
        Originally Posted by steve herman View Post

        Do wire wheels need to turn as fast as a grinding wheels to be effective ?
        some wheels wont wobble at lower speeds even if they are out of balance.

        Just asking,
        Steve
        Originally posted by JoeLee View Post

        I believe I did mention in one of my posts that I can eliminate the vibration by dropping the RPM's by way of my VFD. I'm set up at 1:1 with the pulleys from motor to spindle. the motor runs at I think either 34 or 36 hundred RPM's at 60Hz. If I drop the freq. down to about 49 Hz. the vibration disappears. I don't know where that puts the R's at but if the wheel isn't turning fast enough it'll just scrape rub, frag and over heat all while leaving a horrible finish.

        I think I'm going to order one of those Tormach hubs and modify it to fit the spindle. I really don't have much choice with the spindle on this machine.
        I could make the entire thing but for the price the majority of the work is done. All I will have to do is make it fit and recess one side for the nut.

        JL................
        This change of "vibration" with a change of speed/revs seems to have an element of "harmonics" in it.

        https://www.google.com.au/search?q=g...+and+harmonics

        https://en.wikipedia.org/wiki/Critical_speed

        https://www.google.com.au/search?q=g...haft+harmonics
        Last edited by oldtiffie; 09-10-2016, 02:53 AM.

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        • #64
          I finally got the posts done for the balancing stand. The posts are 1" dia. SS and the rails are hardened and ground shafting with a straightness of .001 in 12" I think. They are 5/8" in dia. and 8" long.
          After boring the hole for the rails I checked to see how accurate I was. All the rails were with in .0002 except teh one post that ended up a bit low at .0004. I doubt that it will decrease the sensitivity of the stand.

          The posts will be mounted on a piece of 3/4" plate as shown. I have to mill the plate to get it flat so I'm not sure where I'll end with the posts being equal when mounted on the plate. I will have leveling adjusting screws on the plate.






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