These HSS (high-speed steel) counterbore step drills are ideal for counterboring bolt type heads or bolts in wood, plastic, and soft metals. These step drills allow you to drill and counterbore in one operation and are less likely to clog that 2-piece counterbores especially in aluminum. The counterbore angle on all bits is 180 degrees or flat. The shank diameter on screw sizes 2-4 is the same as the large diameter. Screw sizes 5-8 have a 1/4 inch shank diameter, screw sizes 9 and 10 have a 3/8 inch shank diameter, and larger sizes above that have a 1/2 inch shank diameter. Special sizes 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.
" data-opinew-shop-id="" data-shop-url="woodshopbits.com" data-platform-product-id="9514425229">