Finger joints are also called box joints. They are easier to cut and assemble than dovetail joints while still providing plenty of strength for the project. Finger joints are cut using either a table saw equipped with a dado cutter, or a router table fitted with a straight bit. Most dado cutters uses a series of blades and spacers -- called a stacked dado set -- that can be adjusted to the proper width.
Finger Joint Applications
Finger joints are used to create corner joints in woodworking projects. They are often seen on boxes and drawers. Occasionally, these joints are used on chests and cabinets when woodworkers prefer an interlaced effect at box corners. The joint resembles a series of evenly spaced notches and tabs (called tails). The tails of one piece slip into the notches of the other. This design offers plenty of surface area for glue.
Whether cut on a saw or a router, finger joints are easier to produce with a jig. These fixtures may be purchased from woodworking stores or they can be made in the shop from scrap pieces of wood. The typical finger joint jig set up includes what's called a "key" or "pin" made to the exact dimensions of the notches and tails. The key fastens to a back board or base. A box joint jig looks similar to a board with a finger (the key) protruding from it.
Cutting Finger Joints
Wood butts up to the key and the operator passes the material through the dado cutter or router bit, cutting a notch into the workpiece. The notch slips over the key and the operator makes another pass through the cutter, creating a second notch. This process continues until all the notches and tails are complete.
After ripping -- cutting lengthwise -- the material that becomes the jig’s key, cut it into two pieces. Mount one piece to the backer board to become the key, and use the second piece as a gauge block. Then cut both boards to be joined using the gauge block to offset one from the other. Then cut the notches in both boards at the same time to ensure proper alignment. Cut the notches about 1/16 inch deeper than desired. Trim the tails or sand them flush after gluing the joint together to make a tight, even finger joint. A handheld, oscillating sanding tool allows you to sand off the excess tail material and dried glue with precision, but a sanding block will also work.
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