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Thread: New shaper bit blowout

  1. #1

    New shaper bit blowout

    Hi all,

    Im hoping for some advice on a grizzly 3/4" rabbeting bit I bought for my shaper. Ive used it ~20 times and the blowout is getting worse and worse. Is this just a cheap bit or am I doing something wrong? Ive run it with a powerfeed, fence, and by hand and get the same affect.

    The 3/4" bore on my shaper fits into a large collet. Its somewhat of a strange design to me and sometimes it feels loose. Maybe thats the problem? Anyone had a similar experience with a shaper like this?

    Let me know your thoughts,

    Patrick
    Attached Images Attached Images

  2. #2
    Join Date
    Feb 2003
    Location
    Bellingham, WA
    Posts
    1,933
    Climb cut will be better, but messier. Use the feeder.

    Nothing should feel loose though...
    JR

  3. #3
    If it's a single speed 8000 rpm machine ,I would say the cutter is too small for low rpm

  4. #4
    Join Date
    Aug 2011
    Location
    New York, NY
    Posts
    2,203
    Might also try a rebate cutterhead with scoring knives. CMT makes one with a 3/4" bore.



    http://www.cmtutensili.com/show_item...~694.100~2~2~3

  5. #5
    Join Date
    Feb 2011
    Location
    Central WI
    Posts
    5,666
    How many passes? Small diameter with no knickers needs almost router speed to get the tip velocity where you want it. As JR suggested, climb cut might be better. Does the spindle attach with a draw bar into the taper? Have you measured runout? I don't think that is the issue, but good to know. Dave

  6. #6
    If you make a zero clearance face for your fence you may reduce the problem quite a bit

  7. #7
    Join Date
    Oct 2005
    Location
    Camas, Wa
    Posts
    3,848
    What wood is that. I see similar things in red oak but this looks like maple. The bit may be dull. I would make a shallow scoring pass first and maybe make a couple or more passes. I agree with the zero clearance fence helping.

  8. #8
    Join Date
    Dec 2006
    Location
    Toronto Ontario
    Posts
    11,236
    Possible issues

    - cutter speed too low

    - cutter diameter too small

    - no scoring cutters

    -dull cutter

    - difficult wood ( climb cut with feeder).

    In other words, basically what everyone before me said............Regards, Rod.

  9. #9
    Thanks for all the advice. I make mostly poplar interior doors. Thats the material shown above.

    I will try a new zero clearance fence. I suppose I have gotten lazy. I have been hesitant to climb cut because I do it mostly by hand as my power feeder isn't the best. I will see how it works though.

    Thanks again!

  10. #10
    Join Date
    Feb 2007
    Location
    Crystal Lake, IL
    Posts
    577
    Just to reiterate......please use the feeder of you're doing a climb cut. Stating this for the new guys that might not know better.

    It gets ugly quickly when spears fly across the shop, and through a wall, at 200 mph. DAMHIKT.
    Jeff

  11. #11
    Join Date
    Dec 2006
    Location
    Toronto Ontario
    Posts
    11,236
    Quote Originally Posted by Jeff Heath View Post
    Just to reiterate......please use the feeder of you're doing a climb cut. Stating this for the new guys that might not know better.

    It gets ugly quickly when spears fly across the shop, and through a wall, at 200 mph. DAMHIKT.
    That's a word to the wise Jeff..............Rod.

  12. #12
    I have the same bit and not had a problem. I do use a zero clearance fence which I think is why I don't have a problem

  13. #13
    Join Date
    Aug 2006
    Location
    Maine
    Posts
    381
    Could one of you clarify what you mean by "climb cutting"? Are you referring to making multiple passes taking off a little more each time?

    Thanks!
    - - - - - - - - - - - - -
    Jim Mackell
    Arundel, ME

  14. #14
    Join Date
    Oct 2005
    Location
    Camas, Wa
    Posts
    3,848
    Fig8-26.gif
    This should explain it.

  15. #15
    Join Date
    Feb 2007
    Location
    Crystal Lake, IL
    Posts
    577
    You always want to feed the wood "into" the direction of the spinning cutter. Going opposite of that, with the rotation of the cutter, is a climb cut, and be interesting if precautions aren't taken.....to say the least.
    Jeff

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