Lee Valley Dog Hole Bushing 3/4"

Hardened-steel drill bushing from Lee Valley for dog holes, 3/4" (19 mm). With it you can make an accurate drilling guide for dog holes from any 38 mm (1 1/2") thick board.
The bushing is pressed into a 25 mm (1") hole in the board. Knurling locks it mechanically in the hole, and a protruding rim keeps it square to the face of the guide, so the bit runs straight down into the benchtop.
The hardened steel withstands the bit running against the bushing without wearing the hole.
Specifications: for 3/4" dog holes, mounting hole 25 mm (1"), for 38 mm (1 1/2") board, hardened steel.