The compasses are inlaid into a custom table top underneath a piece of glass. The coasters were made to match - they also provide an inconspicuous home for the powerful rare earth magnets that affect the compasses.
Now I always know which way is north, and exactly where my cup of coffee is...er, so long as it's always on my compass table.
**Note, the reliability of compasses in mass quantities and close proximity decreases somewhat since compasses themselves are magnets. It still works, and actually results in some pretty cool patterns, but if you're looking for the table to be 100% accurate, I'd recommend not designing a table that places them so closely together. I'm a big fan of the way the table came out, as it's a toy just as much as it about the science of magnetism.**
Step 1: Materials
- 12mm sanded plywood
- table legs - I used 4 Ikea Vika Oleby prefab legs
- 16 7/16" x 1/8" thick glass circular top (I had this custom cut)
- a couple square feet of 6mm sanded plywood
- 2 cork coaster inlay
- 2 rare earth magnet
- approximately 500 "mini compasses". I got mine for around 20 cents a piece off Ebay. It takes 500 20mm compasses to cover a 16.5" circle - crazy I know!
- circle jig
- wood glue
- polycrylic - water based clear satin wood finish
- speed square
- random orbital sander