Laid out and drilled rivet holes in forward bottom cowl hinges. Experimented with making a custom pin removal tool; impractical; abandoned. Added outer ends for threaded stainless steel bottom hinge pins, comprised of a coupling nut and short 6-32 screw. Secured inner ends with captive lock washer nuts. Also made up alternative unthreaded pins with short bend at end. Pondered pros and cons of each.