08/31/2026
Stop joining two boards with one screw — and it was never your technique that made it come apart.
Everybody's first project is two boards and a screw, and everybody's first project opens at the corner. There are two reasons and neither of them is you. A screw driven into the end of a board is cutting threads into fibres running the wrong way, so it strips out under load. And glue on end grain wicks into the timber instead of staying in the joint line, which leaves almost nothing bonding the two pieces. The joint was weak before you picked up the drill.
The first fix costs nothing: drill two holes instead of one. A clearance hole through the top board, wide enough that the screw drops through without biting, and a pilot hole in the board underneath for the threads to cut into. Skip the clearance hole and the screw grips the top board and jacks the two apart rather than pulling them together — that is the thin gap you keep seeing on a finished corner. To size the pilot, hold the drill bit up in front of the screw: you should still see the threads either side of the bit, but not the solid core.
The second fix is to stop asking end grain to hold at all, and put long grain into the joint instead. A dowel runs straight through the joint line. A pocket screw comes in at an angle and lands in the face of the other board. Cheapest of the three, and the strongest per pound spent, is a scrap of wood glued into the inside corner as a block — it turns one weak end-grain joint into two long-grain glue faces, and it is made from what is already in the offcut bin.
None of this shows up the day you build it. It shows up a year later when the corner starts to rack.
Comment JOINT and I'll send you the Joint Card — all ten ways to join two boards with a drill and hand tools, in the order of what they hold.
— The Sage
