Re: lead-screw vs common threaded rod

Hello, and welcome,

I'll go further and say my reply extends beyond your WW environment.

In most cases, the single most important thing is REPEATABILITY.
Fortunately, it is also usually one of the easier things to
get "enough" of... But what is meant by enough?

With CNC, you are making either stand-alone parts, or parts of
assemblies. A stand alone part very seldom needs to be an EXACT size.
And even with assemblies, they usually need only a good RELATIVE fit
with other parts of the assembly. So if the size is inaccurate, or
worse, VARIES due to leadscrew inaccuracies, as long as all the parts
fit together correctly, it all works.

Now if you choose to use such an inaccurate means to produce the
movement of your machine, you may find it necessary to set things up
so that the errors created are created in relationship with each
other (slots or threads that need to match will be cut using the
same "part" of the leadscrew). Temperature and other environment
issues need to be considered as well (and often aren't<G>)

So it boils down to this: If you are making your own assemblies or
stand-alone parts, AND you don't have to work/fit the work output of
OTHERS using their own machines, AND you won't need to make these
same parts later when your machine accuracy has diminished due to low
cost materials/leadscrews... Get the picture?

Hope this helps.

Ballendo (who is still a proponent for low cost cnc; but you need to
know what you're getting/exchanging for the low cost) 10.06nm w/l :-)

P.S. I can make an excellent "one-of" machine using a saw and file as
my "tools". History is full of examples. It is when my machine needs
to fit into a system of parts/tools/people that these issues come to
bear upon my techniques and material choices.


--- In CAD_CAM_EDM_DRO@y..., "jmatthews_interfold" <jmatthews@i...>
wrote:

> Greetings:
>
> In light-duty, woodworking environment - where +/- 1/128 aint too

bad

> (half way to the next notch on the best of cabinetmaker's rules) --
> what are pros/cons of EXPENSIVE lead-screw systems vs good qual
> common threaded rod for setting fences, stops, etc?
>
> New to this group, hope were on the same wave length.
>
> Jack