Because there is a variety of saw blades and bits on the market, gaining a simple understanding of what each type does, where each should be used, and why you would need to know the difference, can save you hours of aggravation and your equipment unnecessary wear and tear. Choose the right blades and bits for the material you’re working with, and the project you’re working on.
Blades and bits vary depending on what their intended use is. For example, they can be used for ripping or crosscutting, or carving or profiling, or can be used for cutting hardwoods, softwoods, sheet goods, or planks of flooring. The quality of the cut and the cleanliness of the sawn edge are a reflection of the type and quality of the blade or bit being used to cut the wood. Following are some general differences and definitions of blades and bits used in our industry.
Circular Saw Blades
Circular saw blades are used for miter saws, table saws, circular saws, track saws, and radial arm saws. These blades are mounted on an arbor that is driven by an electric motor (directly, by belt, or by gears). Saw teeth of these blades may be made of steel or carbide.
The cutting edge of each tooth is ground to a specific profile, which controls how it cuts. Flat teeth shave the wood fibers like a plane, beveled teeth cut them in two like a knife, and triple-chip teeth are mixed with flat teeth to cut tough materials. The mix of teeth on a blade is known as the “grind.” The teeth also are ground to attack the wood at a specific hook angle. Larger angles make more aggressive cuts. The gullet is the space between teeth.
The following are some of the most-common circular blade-types that may be used in our industry.
Ripping blades are used for cutting parallel to wood grain, ripping to width. These blades have a large hook angle (20-25 degrees). These blades have fewer teeth and wide gullets, and are used most-commonly with table saws.
Crosscut blades are used for cutting across the wood grain, cutting to length. These blades have a small hook angle (5-10 degrees). These blades have more teeth and narrow gullets, and are used more commonly with miter saws.
Combination blades are used for ripping and crosscutting wood. These blades have teeth arranged in sets of five – first a ripping tooth preceded by a wide gullet, then four crosscut teeth with narrow gullets. The hook varies between 5-25 degrees, depending on the tooth. These commonly are used with circular saws, and miter saws.
Plywood blades are used for cutting plywood. They are designed to make smooth cuts. These blades have small hook angles (5-10 degrees) with narrow gullets. For cutting hardwood veneer plywood, the blades normally have 80 or more small teeth, whereas when cutting OSB or other substrate plywoods, a more-aggressive blade configuration can be used, such as 24-tooth blades.
Hollow ground planer blades normally are used for sawing operations requiring a smoother cut. They have the same hook angle and tooth arrangement as combination blades, but the teeth have no set, and are available only in steel (not carbide).
Thin-kerf blades are used for ripping or crosscutting hardwood. They are available in rip, crosscut, and combination configurations, and are carbide-tipped only. The plate and teeth are approximately 2/3 the width of ordinary blades. The narrow arrangement of the teeth on these blades leaves a narrower kerf in the wood than other blades.
Band Saw Blades
The band saw blade is a long blade that consists of a continuous band of flexible steel with saw teeth, stretched between two or more idler wheels. Band saws are fast and accurate due to continuous tooth blade action and a slow-moving blade, which allows for more finesse and control. The blade comes down from an upper wheel, through a bearing/saw guide yoke and into an opening in the table to a lower wheel. Each tooth is specifically designed to attack the wood being cut at a predetermined rake angle. The spacing between these teeth is called the “pitch,” and is measured in “teeth-per-inch” (tpi). The different types of blades commonly used in our industry include the following:
Standard-tooth blades are best used for crosscutting, joinery cuts, and smooth surfaces. These also have more teeth per inch and can cut slower and smoother than other blades.
Skip-tooth blades are best used for cutting curves and contours, or thick stock. The teeth have the same profile as standard blades, but are spaced much further apart. These blades also cut much faster.
Hook-tooth blades are best used for ripping, resawing, cutting green or resinous wood, or thicker stock. The pitch is the same as the skip-tooth blade, but the rake angle is about 10 degrees, which allows for a more-aggressive cut.
Jigsaw Blades
Blades are used exclusively for the handheld jigsaw. The jigsaw is a saw that uses a reciprocating blade to cut straight lines or irregular curves in wood. It also will make interior cuts, or cuts within a board without cutting through the work from an outside edge. Most jigsaw blades cut on the upstroke, which is good when used for rough cutting. Reverse-tooth blades have downward facing teeth, which produce clean cuts on the face of the board. These blades vary in their effective cutting length, number of teeth per inch (tpi), and manner in which the teeth are set. The following are some of the more common jigsaw blades used in our trade.
General Purpose: 6-8 tpi, used for rough cuts in wood.
Smooth Cut: 6-8 tpi, used for clean cuts in wood.
Plywood: 12-14 tpi, used for cutting sheet materials.
Detail: 12-14 tpi, used for cutting more-intricate patterns.
Laminate: 10-14 tpi, reverse teeth used to cut laminated material on the down stroke.
Offset: 6-8 tpi, offset blade used for cutting up to a corner.
Scroll-Saw Blades
Blades are used exclusively for the scroll saw. A scroll saw is a small electric or pedal-operated reciprocating saw used to cut fine, intricate profiles and patterns. The fineness of its blade allows it to cut more delicately than a jigsaw. Scroll saws come with a variable speed control to modulate the rate of cut through materials and for adjusting to various blade-cutting capabilities.
Scroll blades for heavy-duty work in wood and soft metals (standard tooth).
Fret blades for fine work in wood and soft metals (includes skip tooth, double-skip tooth, and reverse skip tooth).
Precision-ground blades for cleaner cuts and better control (includes skip tooth).
Metal-cutting blades for work in metals (standard tooth).
Spiral blades for omnidirectional cuts in wood and soft metals (standard tooth).
Router Bits
A completely different concept is the router bit. A router is a machine with a revolving vertical spindle and cutter for milling out the surface of wood. A router is used as a “hand-shaper” to create profiles, decorative cuts, shaping, make joints, and trim wood. A router bit consists of a cylindrical shank and one or more flutes that cut. Bit flutes may be made of steel or carbide. Most bits have straight flutes. Bits with shear flutes leave a smoother cut, whereas bits with spiral flutes help clear material from plunge cuts. Stagger-tooth and chip-breaker flutes are made to cut plywood and particleboard. Some bits have pilot bearings, either on the top or bottom of the cutter head, to guide the bit along the edge of the work or template. Unpiloted bits may have top-cutting flutes or point-cut flutes that allow you to plunge into the wood. Routers normally have either a ¼” or ½” collet, which will determine the bit used with the tool. Although there are hundreds of types of router bits, they all can be organized into two categories:
Groove-forming bits, which cut grooves, dadoes, mortises, and recesses in the work.
Edge-forming bits, which cut rabbets, bevels, ogees, and other shapes around the perimeter of the work.
Sharper is better. Always ensure your blades and bits are sharp. Using dull blades and bits can be extremely dangerous, and will overwork your equipment, resulting in premature wear and tear. Almost all blades and bits can be resharpened at a fraction of the cost of buying new.
Consider the blades and bits that you use on your equipment to be one of the least-expensive, yet most-influential components of any installation. Choosing the right blade or bit for your tool can not only ensure you’re using your tools to their best capability, but also ensures your flooring project will be completed as cleanly and efficiently as possible.
Brett Miller is the vice president of technical standards, training, and certification for the National Wood Flooring Association. He can be reached at brett.miller@nwfa.org.