Four common wood joints you can make 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
A dado is simply a flat bottomed groove cut partially into a piece of stock. This joint is typically used when building shelves.

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.

It is safer to make several passes with your router when making any type of joinery where a lot of wood needs to be removed. If you are making a 3/8" deep dado do two passes taking 3/16" with each pass. This will result in a smoother dodo and be less work for your router. It will also be safer for you since you can control the router better. Continue to set up and cut all the dados you require.

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
A tongue and groove joint consists of a flange on one piece of stock and a groove on a mating piece. The flange fits snuggly into the groove and creates a very strong joint, especially when glued.

Creating a tongue and groove joint is a bit more work then a housed dado but is still rather simple with a router table. First start by cutting the groove. A general rule of thumb is to cut the groove first and cut the tongue to fit. The groove should be 50% of the thickness of your stock.

Start at the router table and fit your router with a straight cutting bit. Adjust the rip fence until it is as close to center as you can get it. Set the height of the router bit so it is about 1/16" deeper then you need. Now simply feed the stock through the bit taking extra care to keep the wood tight to the fence and down on the table.

To get the groove exactly centered run the wood through the router again but this time flip the stock so the opposite face is against the fence.

Now measure the width of the groove and set the height of the bit to half that value. Feed the mating piece of wood through the router, making a pass on both sides to get a tongue that is perfectly centered.

The four types of joints described above will be used most often in day to day wood working. They will likely make up the majority of simple joints that you make. With all the joints above gluing and clamping the stock together will create a joint stronger the surrounding wood and make for very stable projects.