Overview Reviews Product Description Unibit®, 1/4" to 3/4" step drill, 9 hole sizes from 1/4" to 3/4" in 1/16" increments, maximum material thickness 1/8", 3 flatted shank, shank size 3/8", single fluted cutting edge assures true round holes & allows greater control, carded. Irwin Tools Catalog Product Videos Custom Field Manufacturing country US Product Reviews Write a Review Write a Review × Irwin UNIBIT® 1/4 - 3/4" #3 High Speed Steel Step Drill Bit 10233 Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name Review Subject * Comments *