Re: [CAD_CAM_EDM_DRO] Re: Best ball screw prices? (was: Ball screw load ratings)

Well, I use HIWIN preloaded ball screws. My prices have been a lot less than
those mentioned... but I am a business buying
more than one or two.

As far as backlash.... well .005 is a lot. it could cause some serious
instability in a servo system and vibration problems
with any system. .001 is not too bad. Sometimes gravity can provide a
preload (up to a certain acceleration) so slop is no problem.

Stiff preloaded systems require bigger motors though. On some "light
preload" 25 mm screws I measured 60 in oz of
drag torque at a moderate rpm. This also means they can get pretty warm.
Enough to grow some thousandths over 6 feet.
I calculate about .015" with 6 feet and a 20 degree temp rise.
Don't think I slipped a decimal place there.

But I do like HIWIN ok. I sell a little surplus linear motion stuff
now and then and HIWIN cost is so low that it actually competes sometimes
with surplus. What they have little of is service and application
engineering. Like engineering and design guides...
(they tend to be in chinese translated rather broken english.)
Might be fine if I could read chinese.

Leslie Watts
L M Watts Furniture
Tiger, Georgia USA
http://www.rabun.net/~leswatts/wattsfurniturewp.html

----- Original Message -----
From: "Jeff Swayze" <jswayze@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Wednesday, March 07, 2001 8:05 PM
Subject: [CAD_CAM_EDM_DRO] Re: Best ball screw prices? (was: Ball screw load
ratings)


> Reid Tool has the 5/8 .200 screws for just over $1.00 per inch ($73.44 for
a
> 6' screw) and 1" screws for $2.50 per inch. A preloaded 5/8x.200 nut is
> $169.28 while a non-preloaded nut is $29.44. These prices are on par
> with McMaster Carr's.
>
> I'll check with HiWin tomorrow (never dealt with them) but barring an
> incredible bargain I'll plan on buying the screw and non-preloaded
> nuts from Reid. Why non-preloaded? First, their backlash is only .001 to
> .005 inches. I know, I know - "you MUST have ZERO backlash" well, for
> $50 I can find out. Get my system working, see what problems I run into,
> and then I can always upgrade since the mounting is the same. I'm
> sure I can sell the regular nuts if I have to.
>
> Thanks to all who've offered their advice.
>
> Jeff
>
> > > > Does anyone have a source whose price is significantly (5%+) less
> > > > than Thomson's? All I found so far is Reid Tool, and they're a few
> > > > cents cheaper.
> > >
> > > Supposedly, HiWin has the best prices, or at least, very competitive.
> >
> > I got quotes on Hiwin for ballscrews and linear rails. The rails were
half
> > the price of Thomson. The ballscrews were cheaper than Thomson
> from Motion
> > Industries but still significantly higher than Thomson from
> McMaster-Carr.
> > For some reason, they are dirt cheap from McMaster-Carr if you stay
> with
> > 5/8, 3/4 or 1 inch sizes.
> >
> > Be forwarned that McMaster only stocks the 5/8 inch in 13/64 inch
> lead now.
> > You can get the .200 lead from MSC for about 25% more money - still
> a
> > bargain.
> >
> > Doug
>
>
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