Parts for the seat laid out and ready to mark the holes for drilling. This is the first part I encountered that is totally non-prepunched. I have a lot of respect now for the builders of earlier all-metal airplanes. Lots of measuring (i.e. opportunities for error) and marking.

When the diameter of the ScotchBrite wheel is less than that of the grinder, you can't just slide long pieces over it...oh, well. Let that be my biggest problem.

You have to round one of the extrusions (left here) so that it will nestle into a bent corner of the seat back.

Nestling fine, partly drilled.

Ready to disassemble, deburr, prime and rivet.

Doing anything the second time is boring. Good thing I'm not building a four-seater! Here are both seats backs in the fuselage.

It took 12 hours to get both seat backs to this point (i.e. done, ready to paint.)