Re: [CAD_CAM_EDM_DRO] Re: Creating long straight edges

----- Original Message -----
From: drking777 <david.king@...>

> I've been thinking about a method that is a variation on your
> method. What do you think about it? ...
>
> Place the rails on the support beam. At one end of the rail, place a
> cheap laser pointer and at the other end, place a detector ciruit
> with some audible feedback. Make three identical (relatively)
> placards and create the smallest hole possible (end of needle?) in
> each of the placards. Place one of the placards in front of the
> laser and one in front of the detector. Securely affix the third to
> the bearing surface that rides on the rail.

I think it's possible if you could control diffusion in the holes.

>
> Move the bearing along the rail and shim wherever the light is
> blocked. Now, if there exists a material that could be injected (or
> more like oozed) between the rail and the support beam, then it seems
> like this method would be a piece of cake.

Any 100% solids marine epoxy filled with powdered metal and fumed silica
should work.

>Also, it would compensate
> for variations in the rail itself. The variabiltly of the rail would
> be the width of the hole in the placards.
>
> Any thoughts or suggestions?
>
I must have overdone the caffiene today because I just set a construction
laser up on my desk and tried it. The pin hole held about one foot from the
laser makes a 1/8" spot on the wall 12 feet away. With the pin hole one
foot from the wall and the laser about 30 feet away I get a fairly round
spot about .030" diameter.

Of course one might get better results with a precision drilled hole than I
get with a mylar granola bar wrapper and a safety pin.

OK, darnit! Now I'm curious. I have some carburetor jets somewhere. I'll
report back.

Doug