Hole Saw

It's a hole saw to cut hole in cement board (shower installation).
It can also be used for drywall.

Inner holes with #6 drywall screw = 1.5in (38mm) O.D.
Outer holes with #6 drywall screw = 2.25 (57.2mm) O.D.

To be used with a 3/8" drive.

Step file available in download if you need other hole size / drive size.

Install drywall screw (they are harden steel screw) in the hole you need.
There is two version one with a pilot pin and the other for a third screw to pilot the hole saw.
I prefer the screw pilot over the plastic pin pilot. The plastic pin can easily shear during drilling.

No predrill in cement board required for the screw pilot.
Predrill is required in cement board to 1/4in (6mm) for the pin pilot.