Two blades of the same length, width and teeth per inch can differ several times over in price. The difference is what they are made of. All of them fit the same machine; what changes is what they cut well and how long they stay sharp.
Carbon steel.
Most woodworking blades are high-carbon steel. In the common “hard edge, flexible back” type, only the teeth are hardened; the rest of the band stays soft enough to flex round the wheels thousands of times. Carbon-steel blades are cheap, easy to find in any length and sharp enough for nearly all wood. When they go dull, you replace them.
Choose it for: general woodworking, curves, softwoods and most hardwoods, and blades you change often for different jobs.
Bi-metal.
A bi-metal blade has a strip of high-speed steel welded along a flexible spring-steel back, and the teeth are cut into the high-speed steel. The teeth stay sharp far longer and survive heat that would soften carbon steel. Almost all blades for metal-cutting and portable band saws are bi-metal.
Choose it for: metal, abrasive woods such as teak, and work where a carbon blade dulls too quickly. It costs more, so it makes most sense in widths and lengths you use a lot.
Carbide-tipped.
Carbide teeth are brazed or welded onto a steel back. They are by far the hardest-wearing and can be resharpened, and they leave a very smooth surface when resawing. They are also the most expensive, often costing many times a carbon blade, and they need a saw that can tension a wide blade properly.
Choose it for: resawing, very hard or abrasive species, and production work where downtime for blade changes costs more than the blade.
Fine Woodworking’s rule of thumb.
For domestic woods use high-carbon steel, for abrasive woods bi-metal, and for extremely hard species carbide. Resawing benefits from carbide-tipped blades.
What doesn’t change.
The material never changes the size your machine needs. The loop length is fixed by your machine, and the width and thickness have to stay within the range it is documented for. A thicker bi-metal or carbide blade can be too stiff for small wheels; if your manual gives a maximum thickness, stay within it. Teeth per inch and tooth shape are a separate choice, covered in choosing TPI and tooth shape.
Find your machine’s blade size ↗︎Sources
- Roland Johnson, “Essential Bandsaw Blades”, Fine Woodworking #252, January/February 2016.