Re: [CAD_CAM_EDM_DRO] Re: please help........

----- Original Message -----
From: "Lee Studley"

> Doesn't Kayla need thrust bearings on each end of the ballscrew
> to keep it stable when pushing or pulling the table?

It isn't essential that the screw has thrust bearings at each end - indeed,
doing so could cause problems through differential expansion of the screw
leading to binding. On of the best ways to control end float is to fit a
collar to the screw at one end and install a pair of angular contact
bearings each side of this in a tube (making sure that the protrusion of the
inner race is against the collar on both sides). Then you can screw a cap
onto the tube to control the pressure on the bearings. Whether you put
another bearing on the far end of the screw is a matter of choice - in any
case it should just be a plain one that the screw can JUST slide through to
allow for expansion. If your machine has a long thin screw, a bearing will
help stop it whipping at high speed and creating vibration but if your
machine just has a short thick screw which doesn't move too fast, such a
bearing is probably more trouble than its worth. Bearings at both ends
require very precise alignment of the screw and carriage or things will bind
up - a free-ended screw will allow for a little misalignment which we can
probably expect in hobby machines.

Best wishes,
Ian
--

Ian W. Wright
Sheffield, UK


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