Bar runout
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Thread: Bar runout

  1. #1
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    Default Bar runout

    Hello everybody,
    I need to make a lot of parts from 4' long bars, O.D. is 1.750" we don't touch it, inside boring to 3.150" depth, eccentric tolerance is .005 ". I use a bar puller and put 3 plastic sealing rings inside the machine tube. There is almost no runout near the collet, but at the end of the bar it is about .01 ", but not always, sometimes runout is OK - .002", I cannot fix this problem. What to do? Can the Spindle Liner help?

  2. #2
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    Quote Originally Posted by edtcadcam View Post
    Hello everybody,
    I need to make a lot of parts from 4' long bars, O.D. is 1.750" we don't touch it, inside boring to 3.150" depth, eccentric tolerance is .005 ". I use a bar puller and put 3 plastic sealing rings inside the machine tube. There is almost no runout near the collet, but at the end of the bar it is about .01 ", but not always, sometimes runout is OK - .002", I cannot fix this problem. What to do? Can the Spindle Liner help?
    Can you run the bar only an inch or two (or flush even) out of the collet? Then drill/bore past the front of the chuck. This might require you to pull the bar before part-off, but if you do it right you can start the endwork on the next part immediately.

    Second option is a steady rest to pull the bar to center when it is hanging out far from the chuck.

    Sent from my SM-G930P using Tapatalk

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    I've walked but never ran. Sorry couldn't resist.

  4. #4
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    Use centreless ground (aka PG) bar - drawn bar is seldom truly round or straight.

  5. #5
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    Quote Originally Posted by edtcadcam View Post
    Hello everybody,
    I need to make a lot of parts from 4' long bars, O.D. is 1.750" we don't touch it, inside boring to 3.150" depth, eccentric tolerance is .005 ". I use a bar puller and put 3 plastic sealing rings inside the machine tube. There is almost no runout near the collet, but at the end of the bar it is about .01 ", but not always, sometimes runout is OK - .002", I cannot fix this problem. What to do? Can the Spindle Liner help?
    Why doo posters "cross post" ???.....

    Corfusing at best.

    Bar runout

  6. #6
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    ..and post, post some more....:
    Attention SL20 owners


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