stepped cone drill - side and front view
High Speed Steel 2 Flute Stepped Cone Drills are designed for drilling and enlarging perfectly round holes from 1/8" to 1-1/2" diameter in thin materials up to 1/8" thick. No pilot hole is required. Self-starting split point prevents walking. Each hole is automatically deburred by the cutting edge of the next larger size. Ideal for drilling sheet metal, non-ferrous metals, plastics, PVC, laminates, or wood. They are also known as Step Drill Bits or Step Drills.
LARGE DIAMETER SHANK SIZE RANGE APPLICATION HOLES
1/2A 1/4 1/8 - 1/2 by 32nds Common Size Holes 13
1/2B 1/4 3/16 - 1/2 by 16ths Common Size Holes 6
3/4 3/8 1/4 - 3/4 by 16ths Medium Size Holes 9
7/8 3/8 3/16 - 7/8 by 16ths 1/2" Conduit 12
1 3/8 - 1/2 9/16 - 1 by 16ths Common Size Holes 8
1-1/8 3/8 7/16 - 1-1/8 by 16ths 1/2" & 3/4" Conduit 11
1-3/8 1/2 3/4 - 1-3/8 by 16ths 1" Conduit/Tubing 11
1-1/2 1/2 1/4 - 1-1/2 by 8ths Large Holes 11