The router is making an edge joint
The router can be used with its built-in fence to make joints for gluing up boards to make panels or for joining two pieces of plywood edge to edge. Place the mating pieces together and mark the biscuit locations with a pencil on both pieces. The router has a center line on it that you will line up with your pencil lines. With the built-in fence folded down, the router centers the slot in stock that is 3/4 inch thick. When you push the body of the router towards the work, the cutter emerges from the fence and cuts the slot.
The router is positioned this way when making a corner joint
When making joints in the corners of cases, the fence of the router must guide against the two surfaces that will be flush in the final joint. Place the router so that the fence guides against the edge of the stock and the cutter enters the face of the stock. Combine the resulting part with an edge jointed part from the previous Step and you'll have a corner joint. The two surfaces that you selected will be held in alignment by the biscuits while you glue and clamp the joint.
The removable shim and the adjustable fence
This biscuit router comes with a removable shim that automatically centers the slot in 1/2 inch stock instead of 3/4 inch stock. If you are using stock that is thicker than 3/4 inch, you can use the optional adjustable fence. Whenever you set the fence to a desired thickness, cut the slots on both mating surfaces without changing the setting and the resulting parts will line up.
Lining up and cutting the biscuit slots for a shelf
Another useful alignment technique is to place your part on a flat surface and place the base of the router against that same surface. To locate a shelf on the side of a case, place the shelf face down, position the router with its base face down and cut the slots on the ends of the shelf. Draw a line on the side of the case where you want the top of the shelf to be located. Clamp a board on the line and cut the slots with the router placed so that its base is against that board. The top surface of the shelf will now line up with the line.
The biscuits can be made of wood or plastic
The biscuits themselves are made of compressed wood fibers. They are supposed to fit snugly in their slots and when glue is applied to them, the moisture makes them swell and fit more tightly. On humid days the biscuits may fit too tightly to allow you to test fit your joint. You may squeeze them in a vise to adjust the fit.
There are different size biscuits for different applications. The router has a depth stop on it that will vary the depth and width of the slot.
The red biscuits are made of plastic. They are designed for making "field joints" where it is not possible to use clamps. Their surfaces have serrations that point in opposite directions. Once these biscuits are tapped into their slots they are very difficult to remove. Do all of your test fitting with wooden biscuits, then use the plastic ones for your final assembly. Apply glue to the joint and hammer it together with a rubber mallet.
