Square Pegs, Round Holes

Coat the pointy end of the leg with glue (or put a drop in the hole) then stick the pointy end into the hole.

I’m working on a Shaker-inspired stepback cupboard (that will function as a entertainment center for a flat-panel television) for the February 2009 issue of Popular Woodworking. All but the back is frame-and-panel construction, so almost every joint in the piece is a mortise and tenon. To add strength as well as incorporate a traditional design element, I decided to peg all the joints, including the shelves in the upper section that are seated in grooves.

The first decision when pegging is what kind of wood to use for the pegs. You should select a species that’s harder than the primary wood in your project, as you’ll be pounding a square peg into a round hole. You want the hole to reshape to square as the peg it seated…not have the square peg turn into a dowel. Also, consider how much visual impact you want from the pegs –they’re end grain, so they’ll soak up more finish than the surrounding wood. My piece is cherry; my pegs are white oak.

After you’ve selected the wood, mill it to size. I planed the oak to a hair over 1/4″ in thickness, then ripped it square at the table saw using a sacrificial push stick. Make a lot of sticks; you’ll need them.

Use a mallet or hammer to seat the peg. I drilled my holes to 1-1/4″ and my pegs are 1-1/2″.

Lightly taper both ends of each stick. I used an old-fashioned pencil sharpener on the fat, first-grade pencil setting. Don’t sharpen to a pencil point –  the peg should be tapered enough only to get started in your holes. If you don’t have a crank-handled pencil sharpener, you’ll probably have to whittle the end of your pegs – the holes in most automatic sharpeners won’t accommodate your sticks.

Now cut your pegs to length – you want them to be long enough to seat at least 3/4″ into the joint, and it’s up to you whether you’ll seat each one fully, or leave them proud then flush-cut (or sand) them flat. My pegs were each 1-1/2: long; I found it easiest (and safest) to set up a saw hook with a stop and simply butt the sharp end of each stick against the stop, then saw (each one takes only a few strokes). You could also use a band saw, but be careful – your fingers will be very close to the blade. Then resharpen both ends of your remaining stick, and repeat. You need a lot of pegs.

This is the working drawing for the stepback on which I’m pegging the joints. The project will be in the February 2009 issue.

Before pegging your project, make a test board from an offcut of your primary wood. Test a few drill bits until you find the hole size that results in the best-looking seated peg – the smallest round hole into which you can drive a square peg with strong hammer or mallet whacks, without breaking the peg. Start with a drill bit 1/32″ or so smaller than your peg size, and work your way up or down as necessary. With pegs of just more than 1/4″, I wanted to start with a 7/64″ bit…but despite having four cases for brad-point-bit sets in the shop, the 7/64″ bit was missing from all of them. So I settled on a 1/4″ bit instead.

Carefully lay out the hole locations and be conscious not to drill too close to an edge – the heavy pounding could split the workpiece…say at the end of a stile on a door that took three hours to build (thank goodness it showed only on the backside – and a little CA glue took care of the problem). I drilled my 1/4″ holes 1-1/4″ deep into the legs, and clear through the doors and face frame.

Now get ready to whack. Smear yellow glue on the pointy end of the peg (or in the hole), stick the pointy end in the hole, then whack with a hammer or mallet until it’s fully seated and the hole is square. Then (if you made your pegs long enough to leave them proud) flush the peg to the workpiece surface (with a flush-cut saw or sandpaper…or both). On my frame and doors, the pegs went through and had to be flushed on both sides (side note: make sure you fully support any workpiece on which you’re whacking, perhaps by locating the peg hole over a dog hole in your bench). I could have continued whacking and fully seated them to the show surface, but I was afraid of “frenching” my workpiece. Better to make two cuts at each location than dent the show side with a mallet.

With Senior Editor Glen D. Huey’s help, I sprayed the completed project with two coats of shellac and two coats of lacquer. The pegs “pop” and look great…and now, even if I didn’t get enough glue in my mortises, those pegs will hold the joints tight for decades to come. PW

 Megan is the managing editor of Popular Woodworking and Woodworking Magazine.