The dovetail is the most recognisable of all the woodworking joints. Not only is it enormously efficient, but it can also be highly decorative. It has great mechanical strength, and needs little assistance from glue. Dovetails are generally used in situations where two components are to be joined at right angles, though they can also be handy for other jobs such as end-to-end jointing. They are traditionally used in drawer construction where both the lapped joint and the through joint are used.
If you’re experiencing breakout on the front of the vertical board, take a shallow cut across the jig from right to left before routing out the slots.
For maximum strength a dovetail must be accurately cut with the correct slope to suit the timber being used. The generally accepted dovetail slopes for hand cut joints are 1-in-6 for hardwood and 1-in-8 for softwood. The dovetail is a demanding and time-consuming joint to cut by hand. However there are a great many jigs on the market to speed up the process.

To use a dovetail jig successfully it is important to follow certain rules.
• Your timber must be properly prepared and evenly thicknessed. The ends must be square and precisely dimensioned.
• Router cutters must be kept sharp, particularly dovetail cutters, as they are always used at full depth and cannot cut joints in a series of shallow passes like other cutters.
• Your router will need to be fitted with a fine height adjuster, as precise adjustment is vital for dovetail cutting. A useful gadget that will also help you achieve the correct setting is the Trend Depth Gauge.
• Practice on scrap timber before committing your valuable workpiece to the jig.
• Always wear ear defenders and safety glasses when routing.

The basic principles of setting up and using are common to most jigs.
Here’s our step-by-step guide:

Once you’ve assembled your jig according to the instructions, fix it to the surface of your workbench. It’s best to fix it to a piece of plywood or MDF and then clamp that to the bench, so that you can move it out of the way when you need more space. A setting block is needed to check that the relationship between the template, the edge guides and the jig body is correctly fixed. This is made from a prepared square edged board with a line marked 3mm in from each side, and another 15mm in from the front.
Clamp a piece of scrap in the front position on the jig and butt the setting block against it and clamp it down. Make sure it’s clear of the edge guide. Fit the template in place, loosen the top clamp and slide the setting block across until the marked line is just visible on the left hand edge of the jig. Re-clamp the block. The template must now be adjusted so that the marked line across the front of the board is just visible at the back of the template slots. Use the nuts at the end to wind it in or out.
Remove the template without disturbing the setting block, and then slide the edge guide up against the setting block and tighten securely. Repeat on the other end of the jig. Fit the dovetail cutter into the router collet making sure that no more than a quarter of the shank length protrudes. Fix the guide bush set the depth of cut as recommended. Lock the router down. You’re now ready to make your firs test cut. Take a pair of prepared square edged boards, and clamp them in position. Use a straight edge to ensure that they are perfectly aligned.
Fit the template, making sure that it lies flat on the boards, and tighten securely. The router must be held securely and you must take care to keep it level on the template. Put it at the left hand end of the jig, and make sure that the cutter isn’t in contact with the timber. Start up and gently feed the tool into the jig.
Work slowly in and out of each slot from left to right, making sure that the guide bush is in contact with the jig at all times. Check the joint and re-do any slots that are not clear. The joint is loose and also too shallow. To tighten the joint increase the cutter depth and to increase the depth, move the template towards the jig body. If the joint is too tight, raise the cutter slightly, and if it’s too deep, move the template away from the jig.