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.
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Design & DIY
6 speciality drill bits that you need in your tool box
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.
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.
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.
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.
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.
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.
