Re: [CAD_CAM_EDM_DRO] mounting ballscrews onthe ol mini mill help
Posted by
Les Watts
on 2002-10-03 12:22:01 UTC
Good point!
I used an equivalent radial load factor of 1 in those calculations
last night for the R4A so thrust capacity = radial capacity for
that case. This was from an old MRC engineering and design guide.
The ERL charts give thrust values 60 to 100% of radial depending
ball diameter and number of balls for conrad bearings so you are quite
right.
I guess two things are working there. Having all the balls take a thrust
load as you mention helps a bunch. Having the low contact angle act
as a wedge squeezing the balls works the other way. The net effect
is thrust and radial are about the same.
They take light loads simply because they are light bearings-
radial or thrust. I will say the R4A does have impressive capability
for such a tiny bearing though. It was better than what I would
have guessed.
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
I used an equivalent radial load factor of 1 in those calculations
last night for the R4A so thrust capacity = radial capacity for
that case. This was from an old MRC engineering and design guide.
The ERL charts give thrust values 60 to 100% of radial depending
ball diameter and number of balls for conrad bearings so you are quite
right.
I guess two things are working there. Having all the balls take a thrust
load as you mention helps a bunch. Having the low contact angle act
as a wedge squeezing the balls works the other way. The net effect
is thrust and radial are about the same.
They take light loads simply because they are light bearings-
radial or thrust. I will say the R4A does have impressive capability
for such a tiny bearing though. It was better than what I would
have guessed.
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: <bjammin@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Thursday, October 03, 2002 7:29 AM
Subject: Re: [CAD_CAM_EDM_DRO] mounting ballscrews onthe ol mini mill help
> At 08:49 AM 10/2/02 -0400, you wrote:
> >Ordinary deep groove ball bearings are rated for light thrust loads-
>
> Most of these have thrust loads almost as high as the radial load. No
> fooling! Check any maker's cat on that. You might like to consider that in
> thrust, all the rolling elements bear load; in radial load, only about 1/3
> of them do.
>
>
> Regards, Hoyt McKagen
>
>
> Belfab CNC - http://www.freeyellow.com/members/belfab/belfab.html
> US Best MC - http://www.freeyellow.com/members/batwings/best.html
> Camping/Caving - http://www.freeyellow.com/members/batwings/caving.html
> 93% of people killed in workplace accidents are men
>
> 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.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
>
> 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/
>
>