Axial bearing for Z-thread?

This topic contains 4 replies, has 3 voices, and was last updated by Profile photo of Ulli Ulli 1 year, 2 months ago.

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  • #6129
    Profile photo of Ulli
    Ulli
    Participant

    Does the load of the tool and the Z-assembly hang only on the coupler and the Z-stepper motor’s bearing?
    Wouldn’t it be advantageous to use the bearing in the top motor mount to take the load? Two nuts should do the job.
    Maybe an additional lid to press the outer bearing ring into its bed? Does anything speak against that?
    I understnad that the 608s are basically radial-bearings, but they can take some axial load too.
    Pure axial bearings start at 10mm inner diameter.

    #6137
    Profile photo of karltinsly
    karltinsly
    Participant

    Ryan’s kit comes with a 608 bearing for just the purpose you mention. There are no nuts, but the bearing sits in the z motor mount and the rigid coupler rests on it, taking the load off the stepper.

    #6154
    Profile photo of Ulli
    Ulli
    Participant

    Thanks, Karl. Did not realize that, having seen a picture somewhere where a small gap was left between coupler and bearing. I’ll give that a try. So, for the opposite direction, the influence of gravity is taken as being high enough? Otherwise, the nutlock wuld also need some sort of lock for the downward motion, I guess. Kind of safety zone…

    #6172
    Profile photo of vicious1
    vicious1
    Keymaster

    Yup the coupler should rest on that inner bearing in the z motor mount.
    As strange as is seems when you are milling the bit actually wants to pull itself through the material so , yes, all I was really concerned with was that one direction (same as gravity).

    #6173
    Profile photo of Ulli
    Ulli
    Participant

    Imagine what would happen if gravity would work in the other direction… 😉

    Thanks for the explanation. And yes, the pulling force of normal end mills is known. Less in mills with straight cutting edges, and there are even end mills with a thread that pushes the chippings downwards.

    BTW, I made the coupler, the nutlock, and the IE universal tool mount from PETG – that’s another class of definition, hardness (yet elastic) and impact resistance, compared to PLA.

    Cheers,

    U.

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