3 screwrad = 4.3 / 2 + 0.30;
4 shaftrad = 7.5 / 2 - 0.30;
6 diskrad = 12.0 / 2 - 0.25;
18 disktaperrad = diskrad - diskthick / disktaperratio;
19 totallen = shaftlen + diskthick;
22 polygon([[-screwrad, 0],
24 [-diskrad, -diskthick],
25 [-shaftrad, -diskthick],
26 [-shaftrad, -totallen],
27 [-screwrad, -totallen]]);
31 rotate_extrude($fn=25, convexity=3){