Inspiration for this one is from Projects In Metal book 3. It was not meant to be an exact duplicate
but rather a build using materials that I have on hand.
The tapper includes two tapping spindles at present and more could follow. Either spindle can be driven
by the tommy bar or the knurled aluminum knob.
The knurled knobs were made from round bar stock and some flat head screws I had on hand.
The cotters are made with 3/8 aluminum and differ from the method used in Projects in Metal.
Cotter details are here:
In addition to the two spindles for tapping there is a hole locator also. It should work for most
material thicknesses with the two ends. If not then I will just make another.
The Post is 14" long 3/4 inch in diameter drill rod. One groove helps retain it in the column support with
the addition of two locking knobs.
The Rails are 5/8" drill rod by 9 1/4" long.
Spindles are 1/2" diameter drill rod and vary in length.
I still need to wind a new spring for the spindles, the one from stock is not strong enough.
The base plate is 6 1/8" x 9" and 5/8 inch thick aluminum plate. The only steel parts are the parts from drill rod.
Drilling 72 holes can be fun if you have a power tapper. Check out this thread for an inexpensive power tapping system.