Enlarge 3/4″ Holdfast Holes to 1″

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There are a variety of inexpensive and quick ways to enlarge 3/4” holes on your benchtop to 1” (or any other dimension). One of the simplest is to use a 3/4” dowel and a 1” spade bit, a technique I first saw on the Benchcrafted blog.

In a nutshell, you saw a kerf down the dead center of the dowel to create a channel for the spade bit. I used an inexpensive 1” Ryobi spade bit from the home center and found it created a perfect slip fit with a thin-kerf (3/32” wide) table saw blade.

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Then you epoxy the spade bit into the dowel, ensuring it’s perfectly centered in the kerf. After the glue cures, you have a custom stepped-drill bit.

Insert the dowel into your 3/4” hole. Run the drill up to full speed before starting the cut. This will greatly reduce any splintering of your benchtop. Drill about 3” into the benchtop and remove the bit and dowel. Finish the hole with a 1” auger bit.

The Benchcrafted method works perfectly. My only caveat is that you should chose a high-strength, slow-setting epoxy that is heat-resistant. I used a typical 5-minute epoxy. After 10 holes, the epoxy failed.

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That left me with two 3/4” holes on my benchtop that needed to be opened up to 1”.

— Christopher Schwarz