Re: Bearing Lock Nuts on 5/8 in ballscrews

Marcus and John - Thanks for your insight and suggestions.

Does anybody know where I can purchase back issues of Model
Engineer's Workshop or get reprints of Dick Stephen's article...

Volume 103 (December/January 2004/2005) "Retrofitting the X3 Milling
Machine"

I found out how to order a subscription, but I can't find info on
getting back issues.

Mike


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "selbyplus4" <doc@j...>
wrote:

> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "mmeyers1111"
> <mmeyers1111@y...> wrote:
> > Hi folks...
> >
> > I'm going to turn the ends of some Rockford 5/8 inch ballscrews
> and
> > I was wondering if anybody has experience with bearing lock nuts
> and
> > who could comment on a few questions. The lock nut will be used

to

> > preload an angular contact bearing with a 12mm = 0.4724 inch
> inside
> > diameter that is mounted inside a bearing block. I've never used
> > ballscrews or bearing lock nuts so this is very new to me. I'm
> doing
> > this to the ends of 4 ballscrews. I'll be turning them as R-30
> Type
> > C ends (http://www.rockfordballscrew.com/semchart.htm).
> >
> > 1) I noticed that McMaster-Carr (http://www.mcmaster.com) has
> > bearing lock nuts in 2 different sizes that would be reasonable
> for
> > a 5/8 in screw (.391"-32 and .469"-32 ). The bearing portion

(non-

> > threaded portion) of the ballscrew shaft will be turned to

0.4724

> > inch to accept a 12mm ID angular contact bearing. So I guess I'm
> > thinking that the .469 – 32 TPI threads would be the best
> choice
> and
> > the bearing should slip over the threaded portion without

trouble.

> > Does the .469 -32 lock nut sound like the most reasonable

choice?

> > Yes/no?
> >
> > 2) I noticed that the McMastrer-Carr bearing lock nut indicates
> that
> > it is `self retaining' and I don't see any bearing lock nut
> washers
> > available for it. Other nuts I've seen seem to require special
> > washers. Is it true that that all I need is the lock nut itself
> and
> > that a washer would play no role in making sure it stays

`locked'

> > Yes/no?
> >
> > 3) Do bearing lock nuts typically have special threads that
> require
> > a special die to cut them, or can I use my lathe to cut 32 TPI
> > threads with the compound rest set at 29.5 degrees? I'm assuming
> > this isn't a simple yes/no. Sorry.
> >
> > 4) Does anybody use a simpler less expensive approach to
> preloading
> > angular contact bearings on a shaft so that I don't have to
> purchase
> > special bearing lock nuts?
> >
> > 5) Can anybody suggest other/better lock nuts from other

suppliers?

> >
> > Sorry for the length of this folks…
> >
> > Mike
>
> Hi Mike. your answers might well lie in an article by Dick Stephen
> in issue 103 of Model Engineers workshop. Basically what you put

on

> the end of a ball screw has to be absolutely concentric with the
> shaft, or it will not run!. Ball screw shafts are as as hard as
> hades to machine as they are case hardened, firms supplying them
> will anneal the end for you, but at a cost, and ball screws cost

too

> much for me to dare take a blowlamp to them. What Dick advocates

is

> drilling out the centre of the shaft(which is soft), and gluing in

a

> spigot of user friendly EN1A leaded steel. The shaft of that steel
> then being machined / threaded, and whatever else you want to do.
> I have done this on my conversion of an X3 mill and it works. What
> is more, if I can do it anyone can.
> John