Band Saw

A stationary saw that can be used for freehand cutting, the band saw is a very useful piece of equipment.

Band Saws

Photo: ucsd.edu

Some cabinetmakers of distinction assert that the band saw is the single most important stationary tool in the workshop, more valuable even than the table saw. I, for one, haven’t yet unplugged my table saw and offered it at a tag sale; but I have to agree that the band saw is a very-useful piece of equipment.

Unlike the table saw, the band saw is well suited to freehand cutting. That’s one reason it makes cutting curves seem easy, whether for chair seats, arched trim, or rounded tabletops. Nothing makes compound cutting easier than a band saw. (Compound cuts are the sort required for making curved furniture legs, for example, in which a square piece of stock is cut on one side, the offcuts reattached, and then the adjacent side is cut.) The band saw’s depth of cut is unequaled. Among other things, that means that if you are doing repetitive saw work, the band saw will save time, allowing you to cut through several pieces of wood in a stack to make identical parts.

A band saw is ideal for cutting lumber of considerable thickness. And for re-sawing (thinning) wide stock. And for cutting curves, too. A furniture-maker friend of mine says that for shaping chair seats, aprons, or for any cut that isn’t strictly rectilinear, the band saw is indispensable. As its name suggests, this tool relies upon a blade that is shaped like a ribbon. The blade is a closed steel loop that circles two wheels, one above the other. The lower wheel is driven by a motor, usually by means of pulleys or gears.

I should note here that there are smaller, benchtop hand saws with three wheels. The third wheel is located at the rear of the saw, so the blade follows a triangular path rather than an up-and-down one. This means that the throat on a relatively small saw is much deeper than it would be for a similar-sized three-wheel model.

The extra depth is helpful for scrollwork on large workpieces. There is a cost, however, as the sheer cutting power is decreased, and cutting wood at or near the saw’s stated capacity may strain the saw, producing more smoke and screech than cutting. If you want an all-purpose saw, buy a two-wheeler; if you want a sturdier jigsaw for scrolling around panels, a three-wheeler may be the answer for you.

The blade itself is housed in a metal case, visible only where the cutting work is done, in the area immediately above the worktable. Two sets of blade guides keep the blade aligned. One set is fixed below the tabletop, and the other is adjustable to varying heights above the table. The tension of the wheel is set by an adjustment located on the upper wheel housing. Another adjustment controls the tracking of the blade, which should travel at the center of the wheels.

The blade travels in one direction at a great rate, typically two to three thousand feet per minute.

Band saws vary greatly, large ones have been used to saw gigantic redwood trees into lumber; several very popular models these days fit on benchtops. The size of the tool is identified by the depth of the saw’s throat, namely the clearance between the blade and the vertical housing at the rear of the tool (which is, in turn, determined by the diameter of the wheels on which the saw turns). (Common home workshop sizes include ten-, twelve-, fourteen-, sixteen-, and eighteen-inch sizes, but in industry band saws with throats of up to forty-eight inches are common. The capacity of the tool is identified by the depth of the cut the tool will make. A twelve-inch band saw is adequate for most home workshop jobs, typically cutting up to a six-inch capacity. (Cabinetmakers would do well to opt for a larger one, perhaps one with a sixteen- or twenty-inch throat.)

The blades for band saws come in a variety of sizes and types. Each is identified by the number of points (teeth) per inch, the gauge (thickness) of the blade, and its width. Most band-saw blades are between an eighth of an inch and a half inch wide, though larger blades are to be found in bigger machines. The spacing and configuration of the teeth vary depending upon the purpose to which the blade is to be put.

The narrower the blade, the tighter the curve that can be cut with it. An eighth-inch-wide blade will cut a radius of about a quarter inch; a quarter-inch blade will cut a three-quarter-inch hole; a three-eighths blade a one-inch radius; and a half-inch blade nothing tighter than a one-and-a-quarter-inch arc.

As with saber and other saw-blades, more, smaller teeth are suited to cutting metal (in the range of twenty-four teeth per inch) while fewer, larger teeth are used to cut wood. A coarse-toothed band-saw blade with, say, six teeth per inch is best suited to rough-cutting thick lumber, while finer teeth produce a smoother cut.

Band-saw blades also have varying kinds of teeth. Some have cutting teeth set to either side, like those on a handsaw, but with unset teeth called rakers interspersed; others have wavy-set teeth, on which the teeth are set sequentially at a greater (then lesser) distance from the thickness of the band, producing the wavy appearance. Blades with wavy-set teeth are best suited to cutting metal, while blades that have raker teeth, which clear the waste efficiently from the kerf, are best for wood and coarse metals.

Toothless blades are used to cut ceramics, plastics, and for very smooth cuts in other materials. The cutting edge on toothless blades consists of a surface that has tungsten carbide chips bonded to the teeth.

The profile of the teeth varies, too. Skip-tooth blades have deep gullets and are a good choice for general woodwork. For very smooth cutting (which is done at a slower pace), a regular or standard tooth is best. For high-speed cutting (which leaves a coarser cut), hook- or saber-toothed blades are appropriate.

If you have a small band saw, however, you may find that the usual standards don’t quite apply. Many smaller saws do their best work using a narrower blade (one, say, a quarter inch wide) rather than a half-inch or three-quarter-inch band-saw blade. Buy bimetal blades (their teeth are cut from a strip of cobalt steel that is electron-welded to a spring steel blank before the teeth are cut). They’re stronger and last longer.

For the weekend band-sawyer using a small-scale band saw, I’d suggest a bimetal, hook-tooth, six-teeth-per-inch blade for all-purpose work.

The table on a band saw is typically small (a foot square, plus or minus), but don’t be deceived: The saw can and will cut long pieces of stock, and when positioning the tool in your workshop, you should allow for considerable space on either side. The table should have a removable and adjustable fence to act as a guide, as well as an adjustable miter fence. The table itself should tilt; if the model you are considering has a fixed table, look a little further and find one that can be tilted. Some models are sold with a convenient variation, namely, that the housing, with the band-saw blade and pulleys within, tilts with respect to the table, rather than vice versa. This has the distinct advantage of leaving the operator with the familiar, horizontal worktable on which to present the work.