Any large panel or table top should be secured in a way that allows it to expand or contract without splitting. These screw-slot bits let you create screw slots so that panels can be held in place but are able to slide back and forth without splitting the wood or breaking the screw securing them. Both have 12mm (15/32") or 12,7mm (1/2") shanks and the codes 913.201.11 and 813.701.11 are for countersink screws, while the codes 913.101.11 and 813.601.11 are for counterbored screws.

Shank: 1/2" Cutting:13/16" Diameter: 11/64"7/16" Length: 2-1/2"