Re: [CAD_CAM_EDM_DRO] Re: rolled ball screws

Marcus,

Naw I was joking... they are rolled screws for sure.

This thread had me going back searching for lifetime data on
four point contact ball bearings. I didn't find much. Bearing
fatigue life calculations are not rocket science, but you do
have to know some details of the raceway geometries etc.

I saw one small paragraph on the subject on the new HIWIN
site. They did imply that oversize ball preloaded rolled screws
"will eventually lose preload with heavy industrial use after a
long time". Whatever that means. They are so cheap that if they
had half the life of ground double nut or offset pitch loaded screws
they would still be a bargain.

As far as my machines... lots of pictures on the engineering link
below. Details on how I get ground screw accuracy from those HIWIN
rolled units are there.I am actually not doing furniture at the moment as
I accepted a nice fat development contract for low cost encoders.
So the machine is carving metal and plastic encoder prototypes!
The contract is just about done though, and I am anxious to make
sawdust again.The development work money is a real shot in the
arm for the business though. Retail sales are of course slow.

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
Surplus cnc for sale:
http://www.alltel.net/~leswatts/forsale.html

----- Original Message -----
From: "Marcus & Eva" <implmex@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Thursday, January 09, 2003 12:04 AM
Subject: Re: [CAD_CAM_EDM_DRO] Re: rolled ball screws


> Hi Les:
> If they've been giving you ground screws all this time by mistake, you
> will have my undying envy forever.
> I was just quoted a price for a 15" length of 25mm x 5mm pitch ballscrew
> with preloaded nut (not rotating nut-which is actually what I wanted...but
> nevermind).....wait for it...690 bucks US!!!
> I don't even want to think what a 10 foot run might cost, especially in
the
> bigger diameters.