Space Balls: insert these space balls in your rail and stile grooves to center raised panels in their frames, thereby ensuring flawless frame and panel assemblies.
The balls are soft enough to allow expansion and contraction, but firm enough to keep the panel from rattling. They are also designed to help eliminate cracking glue joints. 8-10 space balls per door recommended. If you are using a curved bottom dado slot this spacing must be increased to a minimum of 7/32'' on all sides.