The Kreg Jig

There are many different techniques for joining two pieces of timber, both traditional and modern. One that is proving quite resilient is pocket hole joinery. It is a modern development of the more traditional ‘glue and screw’ method. Using a fundamentally simple concept, it produces a surprisingly strong joint, even when glue is not used. Although I call it a modern joint (with Kreg developing the modern pockethole jig in 1986), the ancient Egyptians pioneered the joint by inserting a dowel through an angled hole, then cutting it flush with the surface.

What is a Pocket Hole joint?

The pockethole is created by drilling a partial-depth hole at an angle into one member of the joint. It stops short of cutting all the way through, and the drill bit is profiled so the hole drilled has a flat bottom. This provides a good square surface for the flat-headed screws to press against. The clever part is the drill bit - it has two diameters. The main diameter cuts the slot and the flat bottomed hole. In the centre of this hole another is cut that is just larger than the diameter of the screw itself, so it acts as a pilot hole to control the direction of the screw as it is tightened and helps prevent splitting.

What is a Pocket Hole joint?

The pockethole is created by drilling a partial-depth hole at an angle into one member of the joint. It stops short of cutting all the way through, and the drill bit is profiled so the hole drilled has a flat bottom. This provides a good square surface for the flat-headed screws to press against. The clever part is the drill bit - it has two diameters. The main diameter cuts the slot and the flat bottomed hole. In the centre of this hole another is cut that is just larger than the diameter of the screw itself, so it acts as a pilot hole to control the direction of the screw as it is tightened and helps prevent splitting.

Which screws to use

Kreg offer a full range of pockethole screws to cater for indoor and outdoor use in most material sizes. Instead of having a Phillips or flat drive, they use a square drive that actually predates the Phillips headed screw. This type of drive provides a number of advantages in this scenario, but it boils down to ease of use and resistance to slipping.

Kreg’s K4 Jig

The K4 is the latest offering in the range of pockethole Jigs from Kreg. It appears to fit a useful niche between the comprehensive K3 and the convenient R3 Pockethole Jig. It provides the basic components that would be used for a vast majority of pockethole joinery jobs.

Easy Joints

The thing that strikes you very quickly when using the Kreg is just how easy it makes creating the necessary pocketholes. It is very simple to set the jig up to suit the thickness of the materials being joined, and only a few seconds are required to cut the pocketholes. The K4 jig comes with an integral toggle clamp which is partly why the jig is so fast and convenient to use. Another aspect is the hardened steel drill bit guide that ensures that the bit is accurately guided, hole after hole. When two holes are needed close together, the fact the jig has three guides in close proximity means that both holes can be drilled without the need to reposition the jig itself.

Feature focus

In some situations, it is not convenient or possible to use the jig in its standard configuration, so the drill guide can be removed and clamped directly to the workpiece.

Not for every project

I don’t use pockethole joinery in every project – because of the size of the elongated oval slot caused in the surface of the workpiece, I tend to use pocketholes in situations where this cannot be seen. There are fillers available, in a variety of timbers (and white plastic for melamine), and you could conceivably use a contrasting timber to produce a visual effect.

On the other hand, it would be hard to find another joinery system more suitable for joining melamine, MDF and other materials that tend to have a very weak end-grain glued joint. This is particularly true for carcass construction for cabinetry and building kitchen melamine (MDF or particleboard cored) cupboards. It’s important to plan a project around the joints and keep them hidden.

Summary

The Kreg K4 System is an excellent investment for people who are not expecting to use pockethole joinery all the time (and therefore don’t want to invest in all the accessories), but want to be able to quickly and easily produce this sort of joint when the need arises. I will stress however, that just because you haven’t invested in the comprehensive kit, you haven’t compromised in the quality of the material or jig construction. This kit provides all the core components needed to start joining in style.

Stuart Lees is the creator of Stu’s Shed (www.stusshed.com), an online woodworking review and tutorial site that has become a primary online resource amongst the Australian and New Zealand woodworking community. He lives in Melbourne.