Re: [CAD_CAM_EDM_DRO] mounting ballscrews onthe ol mini mill help

Well, there isn't going to be much compression load on a 3/8"
screw.... it would buckle unless it was very very short.

I think you could get away with regular conrad type ball bearings
if you deal with the axial clearance. Note that on these bearings
the inner race can move around axially quite a bit. This would cause
massive backlash. But you can use pairs preloaded
against each other. That really turns them into angular contact
bearings with a few degrees contact angle. They are spaced
with an inner and outer sleeve of slightly different lengths.
Do this on one end only.

Ordinary deep groove ball bearings are rated for light thrust loads-
all bets are off if you get shock loads from a crash or something
though. But hey- these are $3 bearings.

You can get single and double row angular contact and tapered
roller bearings easily at places like MSC, Grainger, and Reid
if you want. They can cost much more and yes might be hard to find in
such a small size.

Les

Leslie Watts
L M Watts Furniture
Tiger, Georgia USA
http://www.alltel.net/~leswatts/wattsfurniturewp.html
engineering page:
http://www.alltel.net/~leswatts/shop.html

----- Original Message -----
From: "Kayla Sanders" <tattoos4unme@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Wednesday, October 02, 2002 3:40 AM
Subject: [CAD_CAM_EDM_DRO] mounting ballscrews onthe ol mini mill help


> i have just recently purchased some warner electric 3/8 inch
> ballscrews and nuts and am trying to figure out a way to mount them
> in my mini mill without extensive mods to the mill(mainly because i
> dont have anything else to machine it with!)
>
> im wondering if i absolutely have to use thrust bearings when i
> mount them to the table or if i can use good quality precision
> bearings ,if held firmly on both sides?
> i mean, how much axial force is really going to be put on the
> bearings with a mini mill anyway?
> i ask this because finding thrust bearings to fit this ballscrew
> after machining the ends down to 5/16ths or so is looking to be
> impossible. i can find precision bearings all over the place that
> would fit snuggly on the ends.
> and i think that if i enclose the bearings just down to the
> ballscrew with the motor mounting plate on both sides, that this
> would work.
>
> any ideas or suggestions from you fellow CNC'ers or knowlegable
> people out there??
> thanks for the input if any.
>
> K.S.
>
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