The International Cessna 170 Association

I do a lot of air-to-air photos from my friend's 1953 170. To do this, I take the screw out of the window knob and remove the knob, the washers and other hardware, allowing me to open the window completely. We were just up flying the other day and I reached over to open the window and the knob was gone. I ordered the knob, but does anyone here know what screw I should buy for it?

Since you R&R that screw regularly, why don’t you heli-coil it and use a #4 or #6 machine screw? A PK type screw will eventually work the threads loose in plastic when R&R’d frequently.

Until you do the helicoil, use a ss 4X3/8-TRA

Thank you both!