Dotco Router Guides For Router Bits with 1/4'' Shanks. For use on Dotco 12-10, 12-20, 12-20, 12-25 and 12-40 series. The minimum router bit length (OAL) to be used is determined by the formula: OAL = 1-13/16''+C+P (series 12-10); OAL = 2''+C+P (series 12-20 & 12-25). ''C'' is the ''C'' dimension of the router guide and ''P'' is the desired protrusion of the router bit.
Important: Insert bit into collet as far as possible, then pull out 1/16'' and tighten collet. In an emergency, if it is necessary to pull out the bit more than 1/4'', be sure to insert a short length of blank shank (not to exceed 5/8'' long) in the bottom of the collet before inserting the bit.