On big projects, what additional material(s) might you run into?
         (Different materials require different tooth styles, configurations, and  
          grind angles.) Improper tool and cutting material match can cause
          damage to the hole saw.

2. What size mandrel?( i.e. 1/2" Round or 3/4" Round.)

         (The shank portion of a Hole Saw is referred to as a mandrel.)
         Mandrels are most often used with hand-held drill motors.

3. What size hub thread? (i.e. 3/4"-10 )