Countersinking hardware, such as screws or flathead bolts, is key to a sleek surface and a quality, finished look. But it doesn't always go smoothly, and the multiple bits can lead to tearout and misshapen holes.
Recently, I was making a jig from some hard maple that required precise countersunk holes for hardware alignment. I needed the hole to be placed exactly for registration, so I first drilled out the hole, and then the countersink. But every. single. hole. gave me fits. Once I finished one side of the jig, I was determined to come up with a better solution.
Just to see what happened, I tried the countersink first. I was worried that the bit would wander and not allow the precise placement I was after, but I realized the sharp tip of the countersink bit made it perfectly easy to locate my mark and produce the clean look and round hole I needed to fit the bolts
So, here's my technique for how to make a perfect countersunk hole every time.
Lay out your mark where the shaft of the hardware will go.You can make a starter dimple with an awl, but I found it wasn't really necessary with a nice sharp tip.
Place the appropriate countersink bit on your mark, and drill just beyond where the chamfer meets the flat surface.
Then, you can finish up with a brad-point drill bit, placed exactly in the center of the conical hole left from the countersink.
Of course, if you're creating pilot holes for countersunk screws, you can save a lot of time with these combination countersink drill bits, which drill both a pilot hole and countersink at once. But, if you need a full clearance hole for a bolt, or are using an unusual hardware size, choosing the exact countersink size produces the best results.