Using a router to mill perfect joints
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
A proper joint along with proper wood glue will enable you to join wood in almost any configuration. Below I will cover some of the more popular methods of creating beautiful joints.
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.
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.
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.
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 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.