Homebrew PCBs

>
>> DO  NOT  use the combination stainless/stainless! On one (not CNC)
> machine I
>> had to cut the bound nuts. Better combination is stainless/brass.
>
>
> A little more information on this is wanted.  I use SS nuts and bolts all 
> the time.  some project requrie that.
>
>
> As for the the question of a stainless leadscrew.  Here are some 
> problems.
>
> an oxidizing screw such as steel will need lubracation so as not to rust. 
> Rust will wear out the nut and the machine will loose accuracy.
>
> lubricating such a shaft will create the problem of the lubricating oils 
> picking up dust.  and the dust will become a problem.
>
> a soft metal like brass will wear out from use.
>
> Stainless is preferred because it eleminates many of these problems.
>
> the note about not using a stainless leadscrew on a stainless nut is 
> correct.  I preferr a nylon or some plastic type nut.  I find they are 
> much better for a number of reasons.  and making your own is much easier.
>
> Dave
>
>
I would also think stainless and brass is much better...
Brass is somehow "self greasing", if you let run a brass bearing dry it 
survives much longer than other metals.
I think stainless/stainless may bind.. (the screws i had really felt like 
they are binding, i only wantet
to fasten them once and had no grease nearby - so i didn't care)
With no load there was no friction, only when the screw started
to tighten you could feel the friction of the thread.
It somehow felt like if sand is between the nut and the bolt


I see threre is the danger of dust sticking to it, but maybe some oil on 
the spindle is better than totally dry. (all machines i know with 
ways/threads use oil, even
if they produce abrasive dust).

I think, just for testing the machine it may be ok to use cheap galvanized 
rods.
maybe run a die over it... (dave how do you adjust a die to "clean only not 
cut" - the dies here are not
adjustable... without diamond file ;-).)
If these rods are damaged after some runs that doesn't matter if you later
exchange them with better (ground) threaded rods and nuts....

st