Creating joinery with a router

Creating joints to fasten two or most pieces of wood is the common way to build a wood working project. Learning how can be tricky for those who are just getting started in the workshop. There are four common joints that you can make with a router and use for most of your projects.

You have a number of choices for the joinery that you choose for any given project. You have to consider the situation before deciding which one to use. How much stress the joint will be subjected to, the final look of the joint and glue area should all be part of determining what joint to use

Selecting a joint that is going to maximize strength is important. This is determined by the amount of glue surface of the joint and the direction of any stresses the joint will experience.

Housed Dado
Used when making book shelves or other frames a housed dado is the most common joint. It is simply a flat bottomed groove in a piece of stock.

Using a wood router and a straight cutting bit a housed dado can be easily cut. The easiest way is to clamp a straight edge to your stock to guide the router. With your wood router unplugged measure the diameter of the base plate and take note of the bit diameter. Use the radius of the base plate minus the radius of the bit to determine how far from your layout marks you will need to clamp the straight edge.

Once your straight edge is clamped in the proper position simply guide your router through the cut. Take several passes, increasing the depth of the cut with each pass. This way you are able to control the router easier and reduce the work load on the router. Continue to cut and reposition your straight edge until you have cut all the dados.

Stopped Dado
Ideal for shelves or bookcases that don't have a face frame a stopped dado hides the joint to make a project look better. Stopped dados are created the same way you would make a housed dado. Great for shelves and bookcases without face frames a stopped dado allows a woodworker to hide the joint along the front edge. This still provides the strength of the dado joint but stops just short of the front edge.

Making a stopped dado is the same as a housed dado except you stop at a pre marked point about 1" from the edge of the board.

Rabbet Joint
A rabbet joint is much like a dado except it runs along the edge of a board or piece of stock. To easily make a rabbet joint with your router use a rabetting bit. This is a bit with a guide bearing that follows the edge of the board making a notch cut. The width of the rabbet can be adjusted by changing the size of the bearing. This will reduce the amount of the bit that is exposed to the wood. The depth of the rabbet is determined by the height of the bit in the router.

Rabbets are used mostly along the back edge of a piece of stock to make a recess for a plywood back. They are also ideal for making a recess in a frame for a mirror or piece of glass.

Tongue & Groove Joint
Basically a tongue on one piece of stock that fits into a groove on a mating piece of stock. There is plenty of glue surface area making a tongue and groove a very strong joint.

It is more work creating a T&G joint then it is a rabbet or dado but provides a lot of strength and is quite stable. The groove is best formed with a router, router table and straight cutting bit. You should create a groove that's width is roughly 50% of the thickness of the stock. So with 1" stock your groove should be about 1/2".

Begin by setting up your router in the router table and set the height of the straight cutting bit about 1/16" higher then the length of the tongue. Set up the fence on the router table so you can center the groove. feed the stock through and turn it end for end and feed it through again. This will center the groove on your stock.

With the groove milled in the first piece you can measure the exact width and start to form the tongue. This is simple, place the piece with the groove flat on the router table and set the height of the bit so it is just shy of the groove. This will be the most precise method for getting the tongue the right thickness. Make the pass on the first side flip over the board and make a second pass to complete the tongue.

The router is a great tool for creating precise and attractive joinery. When used with a router table and the right bits you can make almost any type of joinery needed to complete most wood working projects.