Re: [CAD_CAM_EDM_DRO] Affordable ball screws

Bill Vance wrote:

> Hi guys;
>
> Would, (liquid), 90 weight gear lube work for this, or be way overkill?

It would probably be a poor choice. What you want is a very thin film,
so as to make the bearing film very stiff. Air bearings have a stiffness
in the range of millions of pounds/inch (meaning a deflection of microinches
per pound). You'd want to do as well, or better. So, a clearance of a
few thousandths of an inch would be the way to go. You'd need to
have a bunch of tiny holes along the flank of the nut's threads, and let the
oil squirt out from the major diameter all the way along the nut. Just
taking a standard nut and pumping oil into the middle, a la a car crank
bearing, is not going to provide the type of Bernoulli lift forces you need.
So, hydraulic fluid (ATF) is probably a much better choice than 90W
gear lube.

I really don't think this is very practical. A hydrostatic bedway slide is a
lot more doable, and, aside from the oil collection problem, could be
implemented on many standard machine tool slides, as on lathes and
mills. Recovering the oil without the chips and cutting lube is why
the makers of these machines make them somewhat differently from
the standard designs, so that the load bearing areas that have the
oil galleys are always covered.

Jon