Centering a square cap jig
Hello all, may I pick your brains?
I work for a large stair manufacturer and we've been racking multiple brains to come up with a simple, efficient jig for the following:
A specific style of post we make requires that we pre-drill in the exact center of the underside of the post cap. They are always square, but come in varying sizes, and these sizes sometimes have a 16th variance due to shrinkage. What we're trying to come up with is a jig for use with a drill press that would center the drill bit on the cap regardless of differences in size, for rapid mass-production. If they were all identical all the time it would be no problem.
The ideas we've come up with so far have either been far too complicated, awkward to employ, or require advanced engineering techniques we're not sure exist...
Any ideas here?