Re: Bearing Lock Nuts on 5/8 in ballscrews

Hi Mike. A quick note of caution on turning down the ends of ball
screws. The shafts are surface hardened and absolute bastards to cut
through into the softer material. Suppliers will anneal the ends for
you at a price. Another way round the problem is to bore the shaft
from the end and superglue in a spiggot of EN1A leaded mild steel.
That leaves you with a user friendly shaft extension for threading
etc.
Dick Stephen wrote this up in an article on retrifitting an X3
milling mavhine for CNC work. It is in issues 102-4 of the Model
Engineers' workshop mag., the pertinent section being in no 103.
I have tried it and it works a treat.
John

--- 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