I was tired of adjusting my extruder idler block for proper tension. I think that it would be much easier to adjust tension if I have an easy-grip nut cap. So here it is!This one is done in OpenSCAD. I spent a few minutes more to make it parametric. So now you can choose nut size, grip type (none, wing, rib) and presence of support structure (a little cross-like thing in the middle) which makes 3D prints more nice and is easy to remove.In OpenSCAD just use the wingnut(m, grip, support) module.Parameters are: m - nut size (metric) grip - grip type: 0=none, 1=wings, 2=ribs support - presence of support structurewingnut(4, 1, true); will generate M4 cap with wings and support, wingnut(5, 2, false); will generate M5 cap with ribs, but no support, wingnut(10, 0, true); will generate round M10 cap with support.