Brief Description: Drilled seat belt fitting holes out to final size
Drilled three of the four seat belt fittings holes to final size and counter bored the holes from the outside for the washer head screws. The forward LH fitting holes I did not touch for now. I am struggling with what to do for a step. The plans sheet metal step would share fasteners with the seat belt fitting and would be a countersunk screw through the step. I would like a flush step or retractable... Still figuring it out.
I step drilled the holes from the 1/8 pilot holes I drilled some time ago out to 1/4" diam. I then used a counter bore router bit to machine the screw counterbores into the longeron.
The plans have you do all this after glassing the fuselage exterior. Make more sense to be to do it before and then just glass over the screw holes. I will use flox/cabosil to fair out the counterbores prior to skinning.
I sanded some "tooth" into the bottom of the seat belt fittings using coarse sand paper to promote the eventual bonding of the fittings to the pads on the fuselage.
Piloted counter bore, note ref line to control depth
Three sanded for tooth, one in foreground not sanded
