Comprehend the Countersink

If you work in melamine or you’re simply searching for a long-lasting, stay-sharp edge on a countersink, a carbide-wing countersink is the answer.

If you work in melamine or you’re simply searching for a long-lasting, stay-sharp edge on a countersink, a carbide-wing countersink is the answer.

New Designs in Countersinks
Some of the new countersink designs seem to follow the “build a better mousetrap” theory. And while the designs are highly engineered, each focuses on the little-used depth stop with the addition of a rotating element that stops as the depth is reached.

The countersink on the left in the photo above is engineered to the max. It’s a massive countersink with an engraved depth-adjustment scale on the countersink shaft, a single-flute bit drills the pilot hole efficiently and the areas between the flutes are shaped to dispel waste with ease. As the spinning orange plastic cone kisses the wood, the action stops to inform the user the specified depth is reached. On the downside, this bit produces a 1⁄2″ counterbore for a #8 screw.

The new design on the far right in the same photo reminds me of a satellite spinning in space. Again, the black circle rotates as the bit begins its descent. Once the depth is met, the spinning stops, but this tool still leaves a burnished circle on the wood surface.

Additionally, this countersink is designed for both #6 and #8 screws. Don’t try to use a 3⁄8″ plug with this setup.

The countersink in the center of the photo more closely mimics the traditional designs for all-in-one countersinks. It is assembled from three parts including a bit, countersink and stop. The stop is held tight with a single setscrew while two screws secure the bit in the hex shank.

This countersink works great. As the stop collar nuzzles the surface, the spinning action of the stop ceases without any marks left behind. The result is the same even if you’re using a hand-held drill and drilling at an angle.

Most important: Don’t buy the inexpensive bits at the hardware stores that have the stepped solid collar for the clearance hole (see the photo above). These are prone to break and are very difficult to push into the work.

In the end, we recommend a countersink with a tapered pilot bit. The countersink can have two or four cutters – choose the one that matches your preference for long edge life (four cutters) or quick work (two cutters).

We’re not big fans of depth stops. We don’t use them because we don’t countersink screws for a living. Instead, our focus is on getting a strong joint without working too hard. We don’t worry about perfectly tidy holes because our countersinks are generally out of sight; and if they’re not, they are most likely plugged. WM

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About Glen D. Huey

Glen Huey is editor of American Woodworker Magazine, and former managing editor of Popular Woodworking Magazine. He's an accomplished period furniture maker and author of numerous woodworking books and videos (as well as magazine articles).