You need to draw your sketch: a drawing sheet A4 a pencil and eraser a ruler a square 45° a compass
1 - About the length of the sheet, about 5 cm from the edge, draw a straight line representing your wall.
2 - from this line, draw the sectional representation of your pipe to avoid and its distance from the wall.
3 - always from this line, from each side, draw the right section of the tube of the future Gendarme Hat, showing the Neutral Fibers and Outer Fibers of the tube (stop your lines at +/- 6 cm from the tube to avoid) and the distance from there also to the wall.
4 - trace the perpendicular passing through the center of the tube to avoid (pull up your lines well, that's why you must leave at least 5 cm from the edge of the sheet).
5 - to 5 mm of the pipe to avoid, trace (just a small mark in reference) the External Fibers and the FN of the future CdG (5 mm is a good spacing).
6 - FN that you have drawn in point # 3, draw on the top a parallel worth the Bending Radius of the tube of the CdG (RC = 3 X the diam ext).
7 - same thing for the FN at point # 5, but here, it is necessary to make a mark at the top and bottom, on the perpendicular of the pipe to avoid (the bottom mark will be named O and that of the top A.
8 - take the compass in opening O / A (= 2 X RC), seize in O, post this opening on the parallels drawn in point n° 6, these points will be named B and B ', of these points, draw on each one from them the perpendicular passing through the FN of the straight sections of the CdG.
9 - join with a line O / B and O / B '.
10 - you now have the births of your shelves.
11 - to draw your O-stitched and Y-open O / A lines, draw stopping on the O / B and O / B 'lines. Do the same for FExt.
12 - end by pricking in opening B / FN and B '/ FN then B / FExt and there too B' / FExt. It's okay? breathe, you are all pale!
Take your time, think carefully point by point without haste! it is longer to write than to trace.Suggest a tip for this theme