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;
21 echo(disktaperrad, screwheadrad);
22 echo(diskrad, disktaperrad, shaftrad, screwheadrad, screwrad);
25 polygon([[-screwrad, 0],
27 [-diskrad, -diskthick],
28 [-shaftrad, -diskthick],
29 [-shaftrad, -totallen],
30 [-screwrad, -totallen]]);