Re: Size of leadscrew clarification

--- In CAD_CAM_EDM_DRO@y..., John Thompson <rcav8r@c...> wrote:

> I'm going to clarify my goals for a router table here...
>

::::::::::::::::::SNIP:::::::::::::::::::::::

> Note, I'm trying to do this as cheaply as possible, that means

finding

> the "unbuildable" components as inexpensively as possible. I can

machine

> most of the parts, but the Acme stuff is out. I would probably buy

the

> McMaster Carr 1018 leadscrews, but need to find the anti-backlash

nuts

> to fit these.

:::::::::::::::::::SNIP:::::::::::::::::::::

>
> Could a anti-backlash nut be made with Acme nuts and a spring,

figuring

> out some way to attach the whole shebang together?

John, if you only need .005 accuracy, you don't necessarily need anti-
backlash nuts. I used the .200 pitch ballscrews on my mill/drill
conversion and am getting a maximum backlash of .0021 with the
cheapie ($23) nut.

Also, are you really sure you want to use ballscrews? I didn't catch
the size of your table, but for a big one the screws get fairly
cumbersome. They also require extra effort to keep clean (wipers). I
suppose for a smaller table it wouldn't be too hard to enclose the
scews in baffles.

I'm chiming in here as my most recent wild hair is to buid a CNC
router that will handle a 4x8 sheet of stock. I'm looking to build
something like the ShopBot, which uses a rack and pinion drive
system. The rack is upside-down, and the flange it's mounted to
protects it from getting very dusty.

Anyhow, just a thought. Good luck on your project.

-Jeff Swayze