Re: [CAD_CAM_EDM_DRO] Linear Slide Components

----- Original Message -----
From: Lee Wenger <wenger2k@...>
>People regularly bash any use of anything other
> than commercial grade linear slide components? Why, why is it that a
> V-wheel on angle iron or skateboard wheels against a hard flat edge is
such
> a horrible idea?

Actually, it is a very good idea. Skate wheels and angle iron will make a
very good linear rail for a hobby router. Some commercial plasma tables
even use this arrangement, though the wheels they use are inferior to skate
wheels.

Your table won't get .005" accuracy but then neither do most of the
ballslide tables the rest of us build. Accuracy is in the design and
construction, not so much in the components.

>
> I'm not being defensive but rather truly trying to determine the
difference
> between these approaches.

Linear slides are easy to apply - drill some holes and bolt them down.
Skate wheels and angle iron will require more work and more thinking to get
good results.


> Another question I have is how does one go about squaring a large table.

If you put a cheap dial indicator on the end of a bar (or even a stick) then
you have a very accurate distance comparator. Use it to get two rails
parallel within a few thousandths.

A carpenter square will work fine if you take readings from both directions
and average the difference. You can easily obtain .005 in/ft
perpendicularity this way.

>
> Last question, I don't own a mill and will need to make some parts for my
> machine. Do you all have suggestions as to lower cost ways to produce
some
> of the machined parts I need made outside of the traditional commercial
> machine shop?

My first lathe was a drill press and file. My first mill was the same drill
press and a $100 XY table. A little ingenuity goes a long way if you temper
it with patience. You can build a very nice router table with wood and
glue. Just don't get to hung up on this accuracy stuff. It's mostly
bragging rights anyway, like having 550 horsepower in the car you drive to
work every day.

Doug