Router Joinery

Learning how to fasten wood together is critical to almost any wood working project you take on. Today I will go over some of the more common types of wood joints and how to create them using a basic wood working router and some bits.

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.

Use your wood router with a straight cutting bit and a straight edge to guide the router is the simplest way to mill a housed dado. Simply clamp the straight edge to the board as a guide for the router base plate. You will have to determine the proper distance from joint that you will need to set your straight edge. Measure the radius of the router base plate and subtract the radius of the bit you are using. This will give the exact distance from the joint your straight edge will need to be clamped.

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.

To make a stopped dado simply mark the joint about an inch from the front edge and stop the router as you get to that mark.

Rabbet Joint
A rabbet joint is simple a groove or dado that is cut along the edge of a piece of stock. The simplest way to form a rabbet joint is to use a rabetting bit in your router. This is a straight cutting bit whose depth of cut is controlled by a guide bearing. Depending on the size of the rabbet you can change the size of the guide bearing.

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.

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.