Starrett A19 'Oops' Arbor (Fits A1, A2 or A10 Type Arbors)

For use in conjunction with either the A1, A2 or A10 type hole saw arbors (e.g. A1-1, XA2, A1E etc).
Replacing the pilot drill, the 'Oops' Arbor allows diameters to be enlarged by attaching a saw of the same size to that of the existing hole.
Acts as a pilot for the larger diameter saw.
Minimum hole enlargement is 4.7mm (3/16") between the pilot saw diameter and the cutting saw diameter.
Works with the following holesaws because they all have the same screw threads (1/2”-20 & 5/8”-18):
(SH) Constant Pitch HSS Bi Metal Holesaws.
(DH) Dual Pitch HSS Bi Metal Holesaws.
(MPH) TCT Multi Purpose Holesaws.
(CT) Carbide Tipped Holesaws.
(D) Diamond Grit Holesaws.