b'Arbors and AccessoriesH olEE NlarGEMENta rBor"OOPS ARBOR"Replacing the pilot drill, the A19 allows diameters to be enlarged by attaching a saw of the same size to that of the existing hole. This saw then acts as the pilot for the larger diameter saw that is attached to the arbor.awS oleCat. No. EDP Regular Arbor That Fits Outer Hole Saw and Size of Enlarging Diameter Pilot Hole Saw Diameter that Fits A19 ArborKA19 01612 A1 13/16 - 1-3/16" (21 - 30mm), A2 or A10 1-1/4 - 6 (32 - 152mm) 9/16 - 5-1/2" (14 - 140mm) Minimum hole enlargement is 3/16" (4.7mm) between pilot hole saw and cutting saw diameterS HA19starrett.com 25'