RE: [CAD_CAM_EDM_DRO] Affordable ball screws

I agree that oil collection would be an interesting problem.

How would this compare to the crankshaft, connecting rod and camshaft
bearings in an automobile engine? They exhibit relatively loose tolerances
and still maintain the hydrostatic effect.

Granted, I wouldn't want to run those bearings in the open, it would make a
huge mess! ;)

-----Original Message-----
From: Sven Peter [mailto:peteryco@...]
Sent: Thursday, June 20, 2002 7:19 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] Affordable ball screws


Hello Jon,
As you say only a casted nut would work out this way for a short while.
As soon ther is some wear oil will spill all over the place and the
hidrostatic effect will be gone.
Sven Peter

Jon Elson wrote:

>
> Sven Peter wrote:
>
> > >
> > > Nic van der Walt wrote:
> > > .... If you can somehow drill a couple
> > > > of small
> > > > oil feeds around the centre line of the nut and then pump high

pressure

> > > > oil through
> > > > it you form a pretty good imitation of a hydrostatic bearing.
> >
> > Dear Sirs.
> > My little experience from having changed some 5 or 8 ball screws on
> > different machines is following:
> > In a bearing factory I see the case that the screws get pitch damages.
> > The contact area of the balls to nut and screw are only spots. Each time
> > there is a G00 movement acceleration is incredibly high and the
> > carriages inertia gives a hit to the ball contact points. In batch
> > production that are always the same points. Pressure oil feed is good
>
> I'm pretty sure the original poster was thinking of a hydrostatic nut
> retrofit to an Acme screw machine. I think it is a pretty crazy idea, and
> would require hundreds of micro-sized holes drilled in the faces
> of the thread to work. Just squiring oil into an Acme nut will not turn

it

> into a hydrostatic bearing. You have to establish a fluid film under high
> shear in the space between the two surfaces, and a nut's threads
> are a complicated geometry to do this in. If the whole nut was a very
> tight fit against the screw, both at minor and major diameter as well as
> at the flank of the thread, then it might be possible to just squirt oil

in

> the middle. This might work with a cast (a la Moglice) nut. Oil

collection

> would still be a complicated problem, as the screw would likely be
> dripping along its length.
>
> Jon
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
>
> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:

aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.

> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this as a

sister site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.

>
> Post messages: CAD_CAM_EDM_DRO@yahoogroups.com
> Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
> Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
> List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...
> Moderator: jmelson@... timg@... [Moderator]
> URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
> bill,
> List Mom
> List Owner
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

Addresses:
FAQ: http://www.ktmarketing.com/faq.html
FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/

OFF Topic POSTS: General Machining
If you wish to post on unlimited OT subjects goto:
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.
http://www.metalworking.com/news_servers.html

http://groups.yahoo.com/group/jobshophomeshop I consider this as a sister
site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.



Post messages: CAD_CAM_EDM_DRO@yahoogroups.com
Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...
Moderator: jmelson@... timg@... [Moderator]
URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
bill,
List Mom
List Owner



Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/