Originally Posted by NordieBoy
Drill the hole almost all the way through.
Lasted over 2 years so far. Would be better epoxied in but I've got a handful of them. I use them for sump bung bolts too.
This method is better than using 2 other magnets to sandwhich the units in place by magnetic force. On a rally where you may live or die by the odometer I like to know my magnet is securely in place.