I am designing a 3D printed gantry to fit an old photographic enlarger stand. It has a 50x56mm straight extrude that is perfect for the task. So, I am looking at using eccentric spacers to best fit wheels to the bearing surface (as any good citizen would). The question I have is I have a 7.14mm hole to setup, but how far do I set the centre of that hole in relation to the bearing surface? The cam has a 1.5mm range. Note that is not asking for designing the gantry (ignore the lead in story about the photographic enlarger above, that is the context only). However, there is an optimum relationship, I am assuming, when designing with an eccentric spacer to give the best range of motion to gain best adjustment range. I am assuming there is a rule of thumb for the distance of the hole centre from the bearing surface PLUS some rule of thumb for the orientation of the eccentric cam, in relation to the bearing surface, when first fitting together (and before adjustment). Is the major axis of the eccentricity parallel to bearing surface? Or is it perpendicular? If parallel, how far from bearing surface? If perpendicular, does the 5mm hole need to be set towards or away from bearing surface in the design? Note, on topic answers appreciated. Guesses not so much. Sketches gold! Cheers, B
