47640 1/2 Inch Shank CNC Extension Adapter for 1/4 Inch Shank Router
EDiamondTools 1-1/4 in.-7 Male to 1/2 in. Shank Adapter for Core Drilling ADJ01
Amana Tool 47641 1/2 Inch Shank CNC Extension Adapter for 1/2 Inch Shank Router Bits
1/2" to 1/4" Router Bit Collet Extension and Reducer. Extends The Router Bit an Additional 2-1/4" and Accepts 1/4" Shank Router Bits Into the Collet - - Amazon.com