Morse MA45PSN (139069), spring loaded arbor provides a 7/16" solid shank can be used with any standard hole saw with 5/8"-18 thread pitch (1-1/4" to 6-5/8" diameter). The strength of the spring ensures the arbor pins remain engaged during use, effectively handling the torque generated by larger diameter hole saws, preventing thread strippage. Easily change hole saw diameters with efficiency and minimal effort. High speed steel pilot drill for use in wood, ferrous and non-ferrous metals. One (1) arbor per box.