Pocket hole joinery

A pocket-hole joint is a screw joint. A jig guides a stepped drill bit into one piece at a steep angle, leaving a pocket with a pilot hole that comes out through its edge, and a screw driven through the pocket pulls that piece tight against the other. The screw holds the joint, so it needs no mortise or tenon.

Setting up the jig

Kreg's K4 manual sets everything from the thickness of the piece you are drilling. The drill guide is set to that thickness, and the stop collar on the step bit is set by laying the bit in the gauge on the jig and lining its shoulder up with the same thickness mark. The screw length then comes from the same thickness: for 3/4 in stock, a 1 1/4 in screw. The whole chart is on the pocket screw length chart.

Choosing the screw

Kreg's screws have a square drive and a self-tapping point, which is why the pocket needs no separate pilot drilling in the mating piece. Kreg recommends fine-thread screws in hardwoods such as oak, maple and walnut, and coarse-thread screws in softwoods, plywood, MDF and particleboard. Its manual also suggests driving the screw halfway, backing it out to clear the fibres, then driving it home, and testing on scrap cut from the same stock.

Two different thicknesses

Kreg's advice is to drill the pocket in the thinner piece, set the jig and bit for that thickness, and, when the outside faces are flush, use the screw length for the thinner piece as well.

When to use it

The pockets show on one face, so the joint goes where that face is hidden, such as the inside of a cabinet or the back of a face frame, or the pockets are filled with plugs. This site does not compare the strength of pocket-hole joints with other joints: the published tests we found each used a different rig, so their numbers can't be compared or averaged.