Types of Router Bits

 

A router bit is an attachment you can insert into the collet of a router in order to cut different shapes in various materials. In woodworking, router bits are inserted into router collets for cutting joints, making duplicates from patterns, making decorative surface cuts and doing a lot more.

 Typically, router bits are either made of carbide or high-speed steel. Carbide tip bits last longer than high-speed steel bits because they are harder and retain their sharpness for a longer period. High-speed bits are made from carbon steel and they have a high heat resistance.

 The structure of a router bit

The cylinder-shaped bottom end of the router bit which is inserted into the router is called the shank. They are often either a half-inch or quarter-inch in width. Smaller routers use quarter-inch shanks but higher horse power routers meant for heavy duty jobs use half-inch shanks.

 The blade is welded to a piece of steel referred to as the body and it provides the torque to the cutters when they cut through a material. In order to protect the router bit from wood build up, it is equipped with a coating called the finish. The cutter or blade is the part of the bit that actually does the cutting.

Categorization

Router bits are categorized according to the function they perform.  When considering the type of router bit to use for a project, various factors including the size, shape of the cutting edge and the material it will be used on all come into focus. In general, router bits are most commonly used for grooving, rounding over edges or joinery. The following are some of the commonly deployed router bits:

 Straight router bits

                                                                  

                                                Straight router bit

Straight router bits cut right into the material to create a groove. Different types of square-shaped grooves can be cut using a straight bit and these grooves can be cut with the wood grain, against the wood grain (called dado) or along the edge of wood to produce an L-shaped shoulder or rabbet. All these cuts are often used to join two pieces of material. Straight bits can also be used to hollow out an area for an inlay or mortise such as grooving a channel where an inlay can be inserted. They are available in a variety of lengths and diameters.

 Flush trim router bits

                                                                 

                                            Flush trim router bit

Flush trim router bits are essentially straight bits with a pilot bearing at the tip, bottom or both and they guide the cutting arm around the edge of a surface so you can trim any overhanging material to flush perfectly. Flush trim router bits can be used in a hand-held router for trimming purposes. They are great for duplicating patterns from templates but when replicating patterns with a template, a table mounted router is better. They can also useful for veneer trimming or shelf-edging.

 Edge forming router bits

                                                                      

                                       Edge forming router bit

Edge forming router bits are designed to shape the edges of wood. They are very good for making decorative edges. There are various types of edge forming router bits. Some of the common ones include cove and round over router bits. Many edge forming router bits also include a pilot bearing. They are mostly useful for final decoration of a project where the edges have already been established and can serve as guides. 

 Joinery router bits

                                                                

                                            Joinery router bit

Joinery router bits are used mainly for cutting adjoining notches to create solid and durable joints. They include rabbeting router bits which are guided by a spinning pilot bearing at the tip to cut a rabbet (shoulder) in the edge of a work piece. When purchased in a set that includes bearings of different diameters, you can use a single bit to produce rabbets of different sizes.

 Final thoughts

It is vital to understand the type of material you will be working with in order to determine the most suitable router bit for the project. You should also be aware that there are specialty router bits dedicated to specific tasks. For example, raised panel bits are dedicated for shaping the edges of door panels to fit into the corresponding slot in the frame's rails and stiles. The smaller router bits are intended for use in hand-held routers while the larger ones are only meant to be used in a table mounted router.