Counterbores Click on the button below to select the counterbore you need. Alvord Polk Tool Adjustable Capscrew Counterbores Each capscrew counterbore has an adjustable blade. Capscrew Counterbores Standard Sizes, Taper Shank HSS Taper Shank Capscrew Counterbores, 1/32 Oversize, 21CM Series 3500 Metric Taper Shank HSS Taper Shank Capscrew Counterbores, Metric, 21CM Series 4200 Capscrew Counterbores, Taper Shank TiN Coated Capscrew Counterbores