Which program should I use

[fred_dot_u]

Using a CAD type program such as Fusion 360 (free for hobbyists, purchase required for commercial use) or OnShape (online, free) or FreeCAD will provide far better results than blender for an engineering project such as yours. If you are of a mind to embrace programming, OpenSCAD will also allow you to generate precise models.

[ReisiCabo]

Thank you very much ????????