When talking about bandsaw blade design there are probably as many opinions as there are bandsaw manufacturers. So let’s look at the basic ideas and concepts of a band blade to appreciate the critical factors.
The first step in choosing a bandsaw blade is to define the cutting requirements. Some considerations are related to the quality of the cut — smoothness, accuracy or straightness, and curve radius — and some are related to the wood itself: density, depth of cut and grain orientation. I do not believe that speed of cutting should be an issue, but some people also are concerned about speed.
Band blade width
The width of a blade is the measurement from the top of the tooth to the back edge of the blade. The wider blades are stiffer overall (more metal) and tend to track better on the band wheels than narrow blades. When cutting thicker material, the wider blade has less ability to deviate because the back end, when in the cut, helps steer the front of the blade, especially if the side clearance is not excessive.
Special note: When resawing a piece of wood, the narrower blade will actually cut straighter than a wider blade. The force of cutting will make a wide blade deviate sideways, while with a narrow blade, the force will push it backwards, but not sideways. This is not what might be expected, but it is true.
Narrow blades can, when cutting a curve, cut a much smaller radius than a wide blade. For example, a 3/4-inch- wide blade can cut a 5-1/2-inch radius (approximately), while a 3/16-inch blade can cut a 5/16-inch radius. (Note: The kerf determines the radius, so these two examples are typical values. A wider kerf, meaning more sawdust and a wider slot, allows smaller radius cuts than with a narrow kerf. Yet a wider kerf means that the straight cuts will be rougher and have more wandering.)
When sawing hardwoods and high density softwoods like Southern yellow pine, it is my preference to use as wide a blade as possible; low density wood can use a narrower blade, if desired.
Band blade thickness
In general, the thicker the blade, the more tension that can be applied. Thicker blades are also wider blades and more tension means straighter cuts. However, thicker blades mean more sawdust. Thicker blades are also more difficult to bend around the band wheels, so most bandsaw manufacturers will specify a thickness or thickness range.
Smaller diameter band wheels need thinner blades. For example, a 12-inch diameter wheel is often equipped with a 0.025-inch thick (maximum) blade that is 1/2 inch or narrower. An 18-inch diameter wheel can use a 0.032-inch thick blade that is 3/4 inch wide.
In general, thicker and wider blades will be the choice when sawing dense wood and woods with hard knots. Such wood needs the extra strength of a thicker, wide blade to avoid breaking. Thicker blades also deflect less when resawing.
The thickness of the blade is reported in terms of actual measurement; sometimes the thickness is called the gauge.