(thanks to Kemmer & roughrider504 & badmother for the great inspiration).
Notes: materials not shown (quick steel putty - AKA Fast Steel). 3/8 12" threaded shaft. A bunch of 3/8 washers and nuts. A few extra smaller nuts and bolts, a 3" 3/8 bolt. Some creative thinking. An old handlebar made of aluminum to build up some spacers for the new axle..
I must also thank my build team, John and Peter.
1. get an old mountain bike like this, made of steel. Try to find one with a flat handle bar (or as close to flat as possible). Front wheel not required.
Get a road bike frame, something that still has a front brake would be nice.
Pull off the rear trinagle.
Drill out the center of the pivot joint using a 3/8 drill bit.
Test fit your threaded rod through the dropouts.
Test fit the handle bar, it will need to be trimmed and drilled.
Looking good so far !!!!!
Now, break out the quick steel and fill up all the holes, make sure that the axle does not have any play. I measured those spacers from an old aluminum handle bar.. filled it with quick steel and slipped it over the axle..
I found this old spring clamp plate and used it as a holder for the main support bar (made out of the steel handle bar that this old mtb came with..) eye-ball the location of the holes and DRILL AWAY !!