Re: Step repair make me nervous
Reply #33 –
Drill pointing at 135 degrees decreases the chisel point of the drill. Why is this important? Because the point contact decreases, allowing quicker penetration at less force.
RPM (rotations per minute) remains the same but the chisel point SFM (surface feet per minute) is almost zero compared to the outside diameter of a drill.
A small center drill usually has the 135 deg point and a thinned web, along with a stepped dia larger than the end diameter. This aids penetration without hardening ahead of the drill. Center drills work great on sheet metal and/or thin metal.