How tight for drawbar
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  1. #1
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    Default How tight for drawbar

    For my FP1, how much tightening on the drawbar?

  2. #2
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    I have about a 6" cranked handle that I thump with the palm of my hand in low gear.

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    Think it all depends of what you are doing...
    a direct mounted collet holding a 1/8" tool needs less tension on the draw bar than a 7/8 mill or better yet a 3" face mill...
    Your machine is 40 taper so tightening the draw bar becomes less sensitive over the older machines having a Morse #4 taper....

    40 spindles don't (generally) have the issue of stuck tooling in the spindle if things fit properly...
    Draw bar tight....good pull on the factory length wrench (right angle,Allen overall handle length 8") after the taper is taken up.

    The feel is pretty distinct...after the taper makes up there is literally no compression happening, so the tension will get stiff almost instantly once the slack is out....Bit hard to quantify it,
    but think you will feel when it is tight.
    Use higher tension if you are running the original style direct mounting collets with large tools...

    Cheers Ross

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    Very helpful, thanks!

  5. #5
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    Is it reasonable to take a drawbar force chart and convert the force into a torque for the size of thread on the drawbar or is it typical to just go by feel as Ross describes? I'm guessing feel but if you needed some reference to compare your "by feel" to would this be a good method?


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