Fork

This is the fork brazed into one piece. I've started cleaning it up in these photos.

After finishing this much I realized how bad I am at measuring and reading numbers. The mystery device is a pipe bender I fashioned from a couple cut-off bits from a 2x4. I cut an arc that I approximated from several different radii. I then carved a 90 degree grove along the center of the curved edge. This was a clumsy process that involved chisels and an angle grinder, but years of ice carving more than prepared me for the subtleties of carving a small groove into an old 2x4. To avoid collapsing the tube I also packed its end with nails while bending it.

The second image is the fork ends domed into this shape so the bits fit into it.

Shapes

Leaving a lot of important steps out I magically wound up here.

Cutting Miters

Using a right-angle piece of metal I found laying in my neighbor's studio, I marked a center line on all of the tubes. I used the lugs as a template for the joints and then rough cut them with a hacksaw and finished them with a half-round file. Also cut a lot of new shapes into my hands.

The layout ink is Sharpie marker.

Drawing

After reading a book on frame building, Caroline helped me with a to-scale drawing.