Uses 5/16th Threaded rod and standard nuts for customizing.

The friction fit on the slide rulers can be adjusted by adding a strip of electrical tape to the back of the ruler or to the inside face of the balancer surface.

UPDATE:
Added extended double sided ruler that prints in 2 pieces. Will work on adding an additional extension as well.

Uses 5/16 Threaded Rod and standard nuts/washers from any hardware store for assembly and customizing size to fit your need.