Throw three jars with interchangeable lids

The ultimate precision challenge. Three jars. Three lids. Any lid fits any jar.

Requirements

• Throw three small jars with identical gallery dimensions (use calipers religiously)
• Throw three lids with matching flanges
• Every lid should drop into every jar cleanly

Why this is hard

• Tiny variations in gallery diameter or depth compound across pieces
• You need consistency in both the jars and the lids
• Your measurement and throwing precision must be within about 1 mm

This is mastery-level work

If you get 2 out of 3 lids fitting all jars, that's excellent. If all 9 combinations work (3 lids × 3 jars), you have production-level precision.