Our countersink step drills are made from high-speed steel and speed up the process of countersinking flat head screws or bolts in wood, plastic, and soft metals. These bits allow you to drill and countersink in one operation and are less likely to clog that 2-piece countersinks especially in aluminum. Step drill are designed to pre-drill clearance holes in the first piece of wood and pilot holes for the threads in the second piece of wood. You will notice that screw sizes are repeated with the only difference being the pilot length (PL). To calculate the length of the pilot hole (PL) you need in the second piece of wood subract the thickness of the first piece of wood from the length of the screw. These countersink bits complete a normal 3-step operation in one step. The countersink angle on all bits is 82 degrees. The shank sizes are the same diameter as the large diameter (LD). Countersinks with long pilots (PL) are not guaranteed against breakage. Special sizes and countersink angles are available upon request. Legend below explains sizing. Select your item(s) then click Add to Cart.
Legend (in inches unless otherwise noted):
- SS = Screw Size
- LD = Large Diameter
- SD = Small Diameter
- PL = Pilot Length
- FL = Flute Length
Technical InfoW.L. Fuller Inc. is a family owned, third generation, manufacturer of the best countersinks, counterbores, plug cutters, taper point drills, brad-point drills, and step drills. They have over 60 years of experience in manufacturing tools to cut woods, plastics, and metals.
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