Making Bench Dog Holes & Holdfast Holes in your Workbench Top
Now I’ll move onto making bench dog holes and holdfast holes. I have a pretty quick and easy method, so let’s get started!
To make a lot of consistently-sized bench dog holes, I setup a plunge router with an adjustable fence. The fence allows me to add the bench dog holes at a perfectly consistent distance from the edge of the workbench. It also stabilizes the plunge router.
I plunge as deep as I can with a ¾-inch or a1-inch spiral up-cut bit. This setup makes it super easy to just move down the bench as I plunge. The only marks I have to make are the spacing between the bench dog holes.
Then I finish boring the hole with a spade bit. I prefer to use a powerful chorded drill, so I don’t burn up the motor on my battery-powered drill.
Also, you can certainly do this with a brace and bit, but just be prepared for it to take a lot longer, and maybe have holes that aren’t as tight due to movement while you’re boring the holes.
As I’m boring the holes with my drill, I watch or feel carefully for the tip of the spade bit (or the lead screw of the auger bit) to come through the bottom of the workbench. Having a friend watch for you is an even better idea.
I just stop every once in awhile to look, or to feel with my hand to see if the tip of the bit has emerged from the bottom of the workbench top.
As soon as the tip starts coming through the workbench top I stop boring the hole. Then after I’ve gotten all the bench dog holes to this point I flip the workbench top over, and I start boring back through the little hole.
This prevents ugly blow-out, and gives a nice, clean bench dog hole:
And holdfast holes are made in just about the same way (as you can see on the demo piece below), except I usually use a slightly larger spade bit when coming back through the bottom.
And I bore up an inch or two through the bottom of the workbench top.
As you can see from the photo below, the larger hole (bottom half of the wood) helps the holdfast have more room to wedge itself. Also, you can bore a holdfast hole just about anywhere in the workbench top. I bore multiple holes on my workbench tops.
Also, just a side note. I don’t like to use my holdfasts in the benchdog holes. I’ve found that it tends to stretch the dog holes out over time, so the bench dogs won’t fit very well.
I bore holes especially for the holdfasts, as you can see below: