Re: Solid coupler from motor to ball screw?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:

>
>
> turbulatordude wrote:
>
> >Check the specs on the motors bearings. I am using only one

bearing

> >set at the far end, and the bearings of the motor for the near

end.

> >That eleminates quite a bit of the problem.
> >
> >
> This might work on a Sherline, but is not accepted practice with

larger

> leadscrews
> in larger machines. If the far-end bearing was a paired radial-

contact

> set, this would
> be closer to OK. If it is just a simple bearing on the far end,

and

> relying on the
> motor to control the full axial thrust on the screw, then it will

be a

> disaster.
> Most servo motors have very low specs for axial thrust, in the 10 -

50

> Lbs range.
> I have my Bridgeport retrofit designed for 1000 Lbs of axial thrust

on

> the screws,
> and of course, it gets much more in a crash.
>
> Jon

Correct, motors cannot handle any axial loading. When I pulled apart
a stepper, I found the bearings on the tail to be not only a slip
fit, but also fitted with spring washers. wanna talk about movement !

radial only movement. motors, at least the ones surplus and e-bay
are not designed for axial loading of the forces for even small
tables.

Dave