One thing, though. The tube fits inside of the Station 3 fittings, so the inside diameter is really 23 13/16 in, to make up for the width of the fittings. I cut the tube to length on the bandsaw and ground to final shape.
Also, notice the block of wood in the center of the jig. The tube does not touch the engine bearers. A bracket will be welded on for that purpose. So, I made a 15/16 in. block to take up the space. This makes the tube more stable in the jig.
First step after measuring - clamp the side brackets in place.
Here's the tube ready for welding. Unfortunately, tack welding the tubes burned up the side pieces of the jig! I'd like to save the jig for future Jenny builders, so I'll make new side pieces when I get some time.
Here's a close up of the tube after welding. I held it up to the Station 3 fitting so you can see how it goes. It will make better sense soon. Hang on. Next I have to weld the Center Section Wire fitting and the bearer bracket. Plus, the middle of the tube must be cut out and replaced with the curved piece. Such a complex simple piece! Should be back at it early next week. Till then....