Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

There is also one more thing about this CNC that I was generally saving for
myself, but what the heck.

Take a good look at my outer rails, and remember they are really the middle
rail of a 3 rail slide. There is already a groove for ball bearings on the
outside. In other words, a cut, a piece to redirect the ball bearings, and a
piece of the outer rail to hold them in could make a recirculating bearing with
very little work. Able to go long distances without a long second piece since
the bearings travel with it.


The metal for this type rail comes on a big spool of flat metal. It's folded
over as it comes off the spool by 4 or more wheels, and made in long lengths
that are cut and then punched. Special ordered directly from the manufacturer
it shouldn't be a problem to get 10 or 12 foot rail sections. With travel
pieces with recirculating bearings, that means you can make a 4' x 8' sheet
plywood size driller and router for likely less than $200 for the rails, maybe
less than $100. Motors and drivers won't be that much more than for a smaller
CNC. Screw arrangement will be the only part to require much work, but
shouldn't be that terrible either.

There's a reason my controller has 12A MOSFETs and I have 120W steppers on
hand, I just haven't built it yet. I have sign making PC boards that are 5'
long that I even could use a driller that long for too. I just need to get
cranking on it.

Alan