registration widgets

[jaredjennings]

The bottom of the keyboard has somewhere from 3 to 15 pieces (depending on how big I tell them to be). Other than all of them being just the right size and also fitting together perfectly (hah!) I don't know how I'll know they add up to the right size and shape.

If there were a hole, or a bump, or something, in the middle of each bottom piece, I could measure their distances, find out what a ... what a sanding and gluing job I did, and get better at it. I could even imagine printing jigs that mate with these registration widgets, and are easier to 3d-print and get right; when gluing some bottom pieces together you could attach the jigs, then remove them when done.

[jaredjennings]

OK but if they are holes they have to be normal to the surface, not vertical. - Spheres don't change under rotation. Spherical dimples would only have to go in the right position. I think I wanted holes I can fit my vernier caliper into, though. With any kind of dimple or bump, where exactly on the feature should the caliper jaws go? But the holes must not be exactly normal: the sides of corresponding holes must be parallel. If they are both normal to the surface, they will be at angles to each other.

[jaredjennings]

This is to say nothing of the problem that sunk the clamp holes idea: there's already stuff on both the top and bottom surface of the bottom piece; any holes or bumps should avoid these existing features, and then how do you properly express where the hole or bump goes, without trial-and-error manual positioning? And such work would be instantly wasted if you change the size of the bottom pieces, which I've done a lot to trade risk of piece misalignment against time to print and iterate.

[jaredjennings]

Weak idea: small spherical dimples the size of BBs. Buy AirSoft plastic BBs and glue them into the dimples. Use the calipers on the glued BBs.