To follow a curve, a bandsaw blade has to twist a little in the cut. The wider the blade, the less it can twist, so its width sets the tightest curve you can saw. Narrow blades turn tightly. Wide blades track straighter, which is why they are used for resawing and long straight cuts.
What “width” means.
Blade width is measured from the back edge of the blade to the tips of the teeth. Blades are sold in inch widths such as 1/8, 3/16, 1/4, 3/8, 1/2, 5/8 and 3/4 in, or in millimetres, for example 6, 10, 13 or 20 mm.
The tightest curve for each width.
Blade makers and woodworking publishers print charts of the smallest radius each width can follow. They agree on the pattern but not on every figure, so here are two side by side. Where they differ, plan for the larger radius. A radius is half the width of the circle: a 5/8 in radius is a circle about 1-1/4 in across.
| Blade width | Smallest radius, Woodcraft | Smallest radius, chart from Starrett, Lenox and Fine Woodworking data |
|---|---|---|
| 1/8 in 3.2 mm | 3/16 in 4.8 mm | 1/8 in 3.2 mm |
| 3/16 in 4.8 mm | 5/16 in 7.9 mm | 5/16 in 7.9 mm |
| 1/4 in 6.4 mm | 5/8 in 15.9 mm | 5/8 in 15.9 mm |
| 3/8 in 9.5 mm | 1-7/16 in 36.5 mm | 1-1/2 in 38.1 mm |
| 1/2 in 12.7 mm | 2-5/8 in 66.7 mm | 2-1/2 in 63.5 mm |
| 5/8 in 15.9 mm | 4 in 101.6 mm | 3-3/4 in 95.3 mm |
| 3/4 in 19.1 mm | 5-1/2 in 139.7 mm | 5-1/2 in 139.7 mm |
Millimetre figures are exact conversions, rounded to one decimal. Metric widths fall between these rows: a 6 mm blade is a little narrower than 1/4 in, a 10 mm blade a little wider than 3/8 in.
Use the widest blade the curve allows.
A wider blade gives a straighter, smoother cut, so the usual advice is to pick the widest blade that still manages the tightest curve in the job. Never push a blade round a curve tighter than its width allows: it twists, binds, and can break.
What your machine allows.
Every bandsaw takes a limited range of widths, and both ends of the range matter. The guides have to support a narrow blade without touching its teeth, and some guide systems need different inserts or settings for the narrowest blades. A wide blade needs more tension than a small saw may be able to give. Our machine pages show the width range where the manufacturer documents one: the JET JWBS-9, for example, takes blades from 1/8 in to 3/8 in wide. Stay inside the documented range, and if the manual recommends a blade for curves, start with that.
Getting round tighter curves.
- Relief cuts. Before following the line, saw straight in from the edge of the waste to just short of the line, at several points round the curve. As you cut along the line, the waste falls away in pieces and the blade never has to twist further than it can.
- Drill the tightest corners. A hole drilled at an inside corner gives that corner its radius; the bandsaw only has to cut in to meet the hole.
- Change blades for the job. If most of the work is tight curves, a narrow blade for that work and a wider one for everything else beats one blade that does both badly.
- Stop when it fights. If the blade starts to twist, bind or burn, stop and make another relief cut rather than forcing it.
Sources
- Jody Garrett, “Choosing the Right Bandsaw Blade”, Woodcraft, updated April 2026.
- “Minimum Cut Radius for Blade Width”, ACE Makerspace, compiled from Starrett, Lenox and Fine Woodworking data.