Design & DIY 6 speciality drill bits that you need in your tool box By Paul Lewis Published: February 5, 2021 Updated: March 26, 2024 share Share on Facebook Share on Twitter Share on Pinterest Copy Link Cancel View in Fullscreen 1 2 3 4 5 6 7 Photo by Daniel Ehrenworth 1. Combo-pilot/Countersink bits I often use screws in woodworking because they’re fast—no clamping of glued parts. These double-duty bits bore a pilot hole to prevent splitting, then they carve out a perfectly sized recess that hides the screw head. Fill the hole with a tapered plug for a near-invisible mechanical connection. View in Fullscreen 1 2 3 4 5 6 7 Photo by Daniel Ehrenworth 2. Step bits Most bits chew up sheet metal and other thin materials, hogging out the entire hole at once and making a mess. Step bits start small and go big, gradually shearing a larger hole as they dig deeper. Add a little cutting fluid, such as a lightweight oil, for a buttery smooth cut. View in Fullscreen 1 2 3 4 5 6 7 Photo by Daniel Ehrenworth 3. Tapered plug cutters These odd bits cut wood plugs. When the plug is tapped into a mating hole with some glue, the slight taper creates a tight fit. Sanded flush, the plug is indistinguishable from the surrounding wood. View in Fullscreen 1 2 3 4 5 6 7 Photo by Daniel Ehrenworth 4. Self-centering bits If a pilot hole isn’t centred, a not-quite-lined-up screw will pull a hinge out of position. These spring-loaded bits are encased in a collar that matches the hole in the hinge. Line the collar up with the hole, and bore a perfectly centred hole every time. View in Fullscreen 1 2 3 4 5 6 7 Photo by Daniel Ehrenworth 5. Masonry bit Drilling into hard materials requires carbide tips and shallow, arrow-shaped points. Masonry bits have fluted shafts—run them at slow speeds; heat buildup can prematurely dull them. A piece of masking tape on the surface will stop the bit from wandering off the mark. View in Fullscreen 1 2 3 4 5 6 7 Photo by Daniel Ehrenworth 6. Glass bit Glass and tile bits are similar to masonry bits, but they have smooth shafts. You can use them the same way you would a masonry bit. View in Fullscreen Related galleries This family’s barn-inspired bunkie is the ultimate teen hangout spot—and it sleeps 16 This cottager’s fishing-themed privy is aqua-tacular Check out this cottager’s amazing beach bar project 1 2 3 4 5 6 7 6 speciality drill bits that you need in your tool box You won’t need these drill bits every day, but they’re good to have for specialty jobs. You can buy them all over, if you know what you’re looking for. Related Story Buy this, and you’ll never have to worry about a dead car battery