Having stuck many cork bottoms to many coasters and aligning nearly all of them pretty close, I finally made a fixture to get it right from now on:

A plywood disk anchors four arcs cut from a remnant of acrylic mirror left over from the card-suit coasters, using strips of adhesive sheet cut 1 mm smaller than the arcs:

Stick an arc in place, lay the cork inside the arc, and stick the rest of the arcs around the cork:

Squish the arcs in place overnight with Too Many Clamps™:

In use, peel the paper off the cork, lay it in place, ease the coaster atop it, press firmly, remove the perfectly aligned coaster, then put a stack of them in the overnight clamp to solidify the PSA bond.
Should’a done this long ago …
Comments
2 responses to “Coaster Cork Alignment Fixture”
Sir, is such a thing possible? [grin]
Only as a thought experiment.