The composite handle on my '73 oven finally broke. It looked like it might be a difficult repair, but the handle ends (even though they are plastic) appear to be fairly strong.
1. Remove the door, then remove the handle ends.
2. Use a universal tool to carefully clean out about 1/8" inside each end where to old bar connected.
3. Find a suitable "U" shaped aluminum extrusion.
4. Machine (with a table saw, no less) the ends of the extrusion to fit inside the old handle ends.
5. Print a support/insert that will retain the new bar in the handle.
The nifty thing is that this is all retained as one unit by the original handle screws. No adhesive and no additional screws or fasteners.
The parts:
Fit together:
Full handle: