Chisel sharpening angle
Most chisels come from the factory at 25° or 30°. That's fine for softwoods but too steep for hardwoods and too fragile for paring. The right bevel angle depends on the wood you're cutting and the operation — and a small micro-bevel changes the trade-off dramatically. This calculator picks an angle and a sharpening plan.
Calculator
Suggested sharpening plan
Why a micro-bevel is almost always worth it
A primary bevel is what most people sharpen. A micro-bevel is a small extra angle — typically 2° steeper — that's added after the primary is established. Two effects:
- The edge is supported by more steel behind it, so it doesn't roll as quickly.
- The micro-bevel is a tiny area, so it's fast to re-sharpen — five seconds on an 8000-grit stone and you're back to hair-popping sharp.
The trade-off is slightly more cutting force. For paring work where you push the chisel with your hand, that's worth it. For heavy chopping mortises where you need maximum edge strength, a steeper micro-bevel (4°) is right.
The wood angle trade-off
A steeper angle (higher number, e.g. 35°) gives a stronger edge that lasts longer. A shallower angle (lower number, e.g. 20°) gives a sharper edge that cuts cleaner but dulls faster. Hardwoods eat soft edges, so harder wood wants a steeper angle; softwoods let you cut with a finer angle and a sharper edge.
Limitations
- Recommendations are general. Chisel makers' factory angles (typically 25° or 30°) sometimes have specific reasons.
- Doesn't predict edge life — that's a function of hours cutting, not angle alone.
- Doesn't model specific alloys. Cryogenically treated steels cut differently at the same angle.
- Sharpening skill matters as much as angle. A perfectly sharp 30° edge cuts better than a poorly sharpened 20° one.
Frequently asked questions
Can I just use the factory angle forever?
For most chisels, the factory angle (25–30°) is a compromise that works on softwood and doesn't fail immediately on hardwood. With a micro-bevel, you'll get longer edge life. For heavy hardwood mortising, regrinding to 30–35° primary + 4° micro gives noticeably longer edge life.
Should I grind on a grinder or hand stones?
Hand stones (or a slow-speed wet grinder) keep the steel cool. A high-speed dry grinder overheats the edge, softening the steel — that "sharp" edge you just ground will dull in minutes. If you grind, cool the edge every pass.
What grit should I stop at?
For paring chisels, 8000+ grit gives a polished edge that slides through wood. For heavy chopping, 1000–4000 is more durable — a polished micro-bevel can chip on heavy cuts. The calculator's plan assumes a finishing stone is available; adjust if you only have coarser stones.