Steps to fabricating frame and rails – approximately 16 hours
You will fabricate the frame out of 3" square x 1/4" wall tubing you purchase locally. Full plans are included.
Legs should be cross-braced with 1/4" x 1" hot roll flat bar. If braces are welded in place, the holes in the leg tubing are not necessary.
You will fabricate feet for the legs out of 3/8" thick cold roll steel, with 1/2" diameter holes. These will accept standard industrial leveling screws, available from industrial supply houses like W.W. Grainger, MSC, McMaster-Carr, etc.
Frame requires three 20' lengths of 3" square x 1/4" wall tubing.
You will fabricate the two rails from 1/2" x 4" cold roll flat bar. This material generally has a tolerance within one thousandth of an inch, and is the perfect surface for the support and guide cam followers to ride upon.
All that is necessary is to cut the rails to length, de-burr the ends, and drill six holes in them to bolt them to the top of the long frame members. A one inch lip of rail will extend outside the frame pieces, providing a surface for cam followers to grip the rail on the top and bottom on each side of the frame.
The guide cam followers will grip the inside and outside of the rail on the side with the motor. The drive shaft pictured below will extend to the far side of the system, furnishing power to that side of the machine, as well.
We recommend the use of a 3/4" diameter drive shaft for all machines with a 4' or greater width capacity. This enables the machine to be driven from both sides without the need for the added expense or maintenance of a third motor.
We supply the necessary bracket, spur gear, and hardware to build the drive shaft. You supply the 3/4" cold roll round bar.
All that is required is for you to cut the shaft to length, center-drill each end, and drill and tap two set screw holes.
We will be furnishing you with sufficient gear rack to drive the machine from both sides via the above drive shaft.
You purchase some 1/2" x 1" cold roll flat bar, and tack weld the gear rack sections in place as shown at right. You will be doing this for both sides of the X (long) axis and for the Y (short) axis.
The bar will require holes to be drilled through its center at intervals, so it can be bolted to holes in the sides of the long frame members, and to the top of the extruded aluminum gantry.