Choosing circular saw blades
Most saw blades are designed to work best in certain types of cutting operations, such as ripping or crosscutting lumber or cutting veneered plywood or melamine. What a blade does best is determined by the number of teeth, the type of gullet (the space between the teeth for clearing chips), the tooth configuration and the hook angle (angle of the teeth).
Crosscut: These blades have more teeth (typically 60 to 80) set at a moderately aggressive angle with shallower gullets. Usually they're configured with an alternate top bevel (ATB) – meaning that the teeth alternate between a right- and left-hand bevel, forming a knife-like edge on either side of the blade – or a triple-chip grind (TCG), in which flat-top teeth alternate with higher teeth chamfered on both sides. They excel at making smooth, splinter-free cuts across the grain of solid wood.
Rip: These blades have fewer teeth (24 to 30) set at a more aggressive angle with deeper gullets to allow for faster stock removal. They often also come in ATB or TCG configuration, and they excel at cutting with the grain.
Combination: As the name suggests, these blades are designed to work well for both ripping and crosscutting. They typically have 50 teeth set at a moderately aggressive angle that are arranged in groups of five: one flat-top tooth and four ATB teeth, with smaller gullets within the groups and a larger gullet between the groups. A good choice for woodworkers who want to be able to perform a variety of cutting operations without having to change blades.
General purpose: These blades are designed to deliver great results in most applications, including cutting solid wood, plywood, laminated wood and melamine. They typically have 40 teeth set at a moderate to aggressive angle with either an ATB configuration or a HiATB configuration (in which the angle of the bevels is steeper). The number of teeth and the depth of the gullets combine to provide both adequate stock removal and clean cuts. Another good choice for woodworkers who want to be able to perform a variety of cutting operations without having to change blades.
Cutoff: These blades are designed specifically for crosscutting with miter saws and radial arm saws. They have a high tooth count and ATB or HiATB configuration. Specific blades are available for sliding compound miter saws/radial arm saws and stationary miter saws.
Specialty blades: These blades are designed for cutting specific materials, such as veneered plywood, plastics and laminates, melamine and non-ferrous metals.
Choosing bandsaw blades
Several considerations should guide your selection of a bandsaw blade:
Blade length: Check the owner's manual that came with your machine.
Blade width: This is the measurement from the tip of the tooth to the back of the blade. In general, you want to select the widest blade your saw will allow for a given situation because wider blades are less likely to deflect during the cut. But blade width ultimately depends on whether you will need to cut curves and on how tight those curves will need to be. The tighter the curve, the narrower the blade will need to be. Wider blades work for well for gentler curves and resawing work.
Blade style or form: This refers to the arrangement of the teeth.
Standard-tooth blades typically have a large number of teeth close together. They provide smooth cuts but require a slower feed rate, making them especially well-suited to crosscutting operations.
Skip-tooth blades have fewer teeth, and they're spaced more widely (as if every other tooth has been skipped). They allow a faster feed rate but don't cut as smoothly as a standard-tooth blade. They're often used as a sort of general-purpose blade.
Hook-tooth blades typically have a low tooth count, and the gullets between the teeth are machined at an angle that makes this type of blade the most aggressive at cutting. It's the best choice for ripping and resawing.
Blade TPI or pitch: This is the number of teeth per inch. The higher the TPI, the smoother the cut but the slower the feed rate will need to be. It's important to match TPI to the thickness of the material being cut. (At least three teeth – but not more than 20 – must be in the workpiece at any given time during the cut to avoid blade damage.) A 3 TPI blade works well for resawing and cutting thicker stock. A fine-toothed blade (18 to 32 TPI) should be used for thin stock. For 3/4" stock, use a 4 TPI blade for faster cutting and a 14 TPI blade for a smoother finish coming off the saw.
Choosing jigsaw blades
Typically, you'll want to choose a blade designed for your cutting situation. Blades for different applications are available, with blade material, tooth count (TPI) and tooth set optimized for those situations. You'll also want to keep in mind what type of blade shank your jigsaw requires for mounting, as well as the thickness of the material you'll be cutting. The blade should be at least 1" longer than the thickness of the material.