Cut perfect rabbets with a router bit
Virtually every cabinet you build uses rabbet joinery somewhere: for lock-rabbet drawers, on inset doors, as a recess to house the back of a bookcase, or to rest glass in a door. A rabbeting router bit helps you make them all, and cuts rascally rabbets on curved edges, such as an arch-topped door—something not possible with a tablesaw.
Bearings give bits versatility
Rabbeting bits typically come in one of two diameters—1 1⁄4 " or 13⁄8 "—and can be purchased alone or with a set of replaceable bearings that alter the cutting width of the bit.
Quick Tip! Check the spin of the bearing before using a rabbeting bit. Some bits use stepped washers between the bearing and bit, as shown below, and if installed upside down, will keep the bearing from spinning.
The chart, below, shows the rabbet that results from using various bearings with a 13⁄8 "-diameter rabbeting bit. If you have a different diameter bit—or bearing—you can easily calculate the resulting rabbet.
To determine the width of your rabbet with a specific bearing, subtract the bearing's diameter from that of the bit; then divide that result by two. Or, to determine which bearing to use for a specific rabbet size, simply multiply the rabbet width by two; then subtract the result from the bit diameter.
Rabbeting bits hog out large amounts of material, so minimize tear-out by making several light passes rather than a single deep one. Begin your rabbet with the router set to take a 3⁄8 "-deep cut at full width, making increasingly deep passes. Also, the large diameter of a rabbeting bit requires a slower router speed—from 16,000 to 18,000 rpm—to perform at its best.