Re: CNC Router How-To's

On Mon, 10 May 1999 01:40:30 EDT, Jonty50@... wrote:

>Umm.. I have more hobbies than time or money unfortunately.

Gee, HOW unusual. -not- Heh.

>Jon is fine.. I saw there was already another Jon here so used the
>untruncated moniker to try and avoid confusion.

Ahh, yup, gotcha.

>I've been mulling several different translation options. There are linear
>driver steppers that have a built in lead nut and ride on a lead screw. I had
>thought to place a lead screw on either side of the table for the 96" axis
>and just allow a linear stepper on either end of the gantry to carry it. This
>plan avoids the whipping problem associated with turning long lead screws at
>high RPM.

Yeah, and it's used on several largish gantry systems I've seen on the
Web. Me bein paranoid, I worry about losing a count, and racking the
gantry, rather than the racking forces of possible imbalance on the
guides. Guess we all have our boogie-men to deal with.

>Another option would be a belt drive using a toothed belt and gearwheels. I
>have all the parts for this option and am currently designing the gearboxes
>required to allow a 0.0005"/step cog belt system. Belt drive is nice because
>it has inherent dampening and cushioning properties and also doesn't mind a
>some dirt and grit much. Use the larger size belts (I'm using 1" wide "L"
>belting) and they are remarkably strong.

Keep us posted; this sounds interesting for the "router-in-the-large".

>For my purposes,. I'll be delerious if I get 0.002" repeatability, 0.010"
>wouldn't be unusable.

Yeah, for my foam routing purposes too, 0.010" would also do OK.

>The nice
>thing about the BW wheels riding on hardened rod is that the contact area is
>so small and hard that it just cuts right through most crap that gets on the
>rods.. BW touts the "wiping action" of their wheels on their V track and it
>does seem to work reasonably well that way too...

Ahh, I see, interesting; a place where concentrated force works to your
advantage.

Thanks for the feedback.

Gar