[skiddaw]

My first attempt at a CNC Router is based on David Steele's book with an old EIA 430 Plotter (circa 1972) as the base which I purchased from goverment surplus some 25 years ago. The U-frame sides are substantial at 6.5" high, 3.5" wide and 1/2" thick. The internal dimensions of the frame are X-31", Y-43". The two X-rails are 1" D, and the Y-rail is solid 1/2"D. I've added 5.25" MDF to stiffen the gantry and a top rail of 3/4" conduit to support the Z-carriage.

The existing X/Y drives use 1mm cables which I might just try and run for starters before I go adding leadscrews. So far the local hardware stores have provided everything apart from the motors which I purchased from Toronto Surplus.

I drilled the holes in the conduit by clamping it to the supporting AL channel and running that along a guide in my drill press. I used 1/4"D square nuts inside the conduit and positioned them there using a 1/4"D magnet from Lee Valley sunk into a small wooden rod.