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Thread: milling head runout

  1. #1

    Default milling head runout

    i have been having some problems with a Grizzly #G0516 lathe combo.
    only had the thing for about 3 days & the switch went out . about 3-4 days later i tried to get the draw bar loose, it was stuck & after a lot of taping with both a dead blow & brass mallet it would not come loose. after calling the tec. service dept. the guy told me that they can become really stuck in shipping & that i should hit it harder. well i did,got it out & it was now bent. after talking with them & sending in a video of the wobbling bar they let me send it back to get it repaired or exchanged for another one because i was not at all happy with it & had been trying to get it exchanged.
    well i got it back after about 3-4 weeks, opened it & there was not any change made to it.
    ok now i am really pissed, called the customer service to find out what was up & was told that there was nothing wrong with it. ok i can live with the draw bar being a little bent if it doesn't affect the performance but it looks like the spindle is wobbling & when i told the lady about it she said that it was checked by the tecs. said that it was acceptable!
    now i admit i am not a machinist but i have been working with woodworking machines all my life & have my own wood shop ( furniture & cabinets) & that just doesn't add up.
    how much wobble should there be in a "precision" mill spindle?
    thanks for reading my rant & any advice would be appreciated;
    madbear

  2. #2
    Join Date
    Mar 2011
    Location
    Iowa
    Posts
    707

    Default

    How exactly did you determine the spindle is wobbling?

  3. #3
    Join Date
    Jun 2010
    Location
    St. Louis
    Posts
    996

    Default

    Are you seeing the drawbar on top of the spindle wobbling or are you measuring spindle wobble at the bottom end of the spindle?

  4. #4

    Default

    at first i just eyeballed it but i just went out & put the dial indicator on a 1/4" endmill & it showed to be 2,000 out.

  5. #5
    Join Date
    Aug 2006
    Location
    Beaverton, OR
    Posts
    7,188

    Default

    You are measuring wrong. You need to use a test indicator on the internal taper of the spindle.

  6. #6

    Default

    will check it tomorrow
    thanks

  7. #7
    Join Date
    Feb 2007
    Posts
    2,078

    Default

    A bent drawbar is not good either. It will enter the threads in your r8 collets at an angle,and eventually something will get wallowed out. Either the draw bar or the collets. You can straighten it to a reasonable degree yourself,can't you?

    Doesn't sound like good customer service.

  8. #8
    Join Date
    Jul 2008
    Posts
    1,489

    Default

    I'd bet this is a MT3 taper for the mill. Can you go thru Grizzly's manual and give the part name for exactly what part other than the draw bar that has the wobble?

    (Sigh) I guess it's easy to reccommend using a BFH when you don't own the machine. While MTs do work and have for a lot longer than I've been alive. There's far better spindle tapers such as that R-8. That doesn't help with your problem though.

    Aside from this problem, Little Machine Shop In California offer a drop in replacement spindle with an R-8 taper. Depending on just how much MT3 tooling you've bought, You really might want to consider that option.

    Pete

  9. #9
    Join Date
    Jan 2004
    Location
    Independent principality of Sinquefieldia (formerly Missouri)
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    With some small amount of adapting, one can make an "ejecting" drawbar......

    I made one for the Lewis mill I have.... now, instead of beating on the drawbar, all I have to do is pop the taper out with a squeeze of my hand on a couple of wrenches..... NO pounding, no drama, no brinnelling of the bearings with a BFH.

    it's SO easy....... and mine uses an MT3 in the spindle. They can indeed get well and truly stuck.

  10. #10
    Join Date
    Sep 2010
    Location
    Wallkill, NY
    Posts
    556

    Default

    Quote Originally Posted by J Tiers
    With some small amount of adapting, one can make an "ejecting" drawbar......

    I made one for the Lewis mill I have.... now, instead of beating on the drawbar, all I have to do is pop the taper out with a squeeze of my hand on a couple of wrenches..... NO pounding, no drama, no brinnelling of the bearings with a BFH.

    it's SO easy....... and mine uses an MT3 in the spindle. They can indeed get well and truly stuck.
    That sounds interesting. Got a link to more information on it? I wince every time I 'tap' the bar on my little griz.
    ----
    Proud machining permanoob since September 2010

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