Quick answer: a rasp steel knife is a knife forged from a farrier's rasp, the coarse steel file a farrier uses to trim horse hooves. Quality rasps are made of high-carbon steel, so the finished knife can be hardened to hold a keen edge. The rasp's tooth pattern is left on the flats of the blade, which gives rasp knives their rugged western look.
How is a rasp steel knife made?
- Select the rasp. The maker starts with a high-carbon farrier's rasp.
- Anneal and shape. The steel is softened with heat, then forged and ground into a blade profile.
- Keep the teeth. The cutting edge is ground clean, while the rasp teeth are left visible on the upper blade and spine.
- Harden and temper. The blade is heated and quenched to harden it, then tempered so it is tough rather than brittle.
- Fit the handle. Scales of wood, horn, bone, resin or Micarta are pinned on, and the edge is sharpened.
Is rasp steel good for knives?
Yes, rasp steel is good for knives when the rasp is genuine high-carbon steel and the heat treatment is done correctly. A well-made rasp knife takes a very sharp edge, is easy to resharpen in the field and is tough enough for ranch and hunting work. The quality of the heat treatment matters more than the fact that the steel started life as a file.
Rasp steel compared with D2 and Damascus
| Property | Rasp steel | D2 tool steel | Damascus |
|---|---|---|---|
| Type | High-carbon steel | High-carbon, high-chromium tool steel | Layered forged steel |
| Edge retention | Good | Very good | Good to very good |
| Ease of sharpening | Easy | Harder | Moderate |
| Rust resistance | Low; needs oil | Moderate | Low to moderate |
| Look | Visible rasp teeth | Plain or coated | Flowing layered pattern |
Why are rasp knives popular with cowboys?
Rasps are a familiar tool in horse country. Turning a rasp into a belt knife is a long-standing western tradition, and the textured blade makes each knife easy to recognize. The teeth also give the spine extra grip under the thumb during controlled cuts.
Do rasp steel knives rust?
Yes. Rasp steel is high-carbon steel, so it will rust if it is put away wet. Rust is easy to prevent:
- Wipe the blade clean and dry after every use.
- Rub on a thin film of mineral oil, paying attention to the grooves between the teeth.
- Do not store the knife long-term in a damp leather sheath.
- Expect a grey patina to form over time. It is normal and helps protect the steel.
How do you sharpen a rasp steel knife?
Sharpen a rasp steel knife like any carbon steel blade: on a whetstone or field stone at about 20 degrees per side, then strop on leather. Carbon steel responds quickly, so a few minutes usually restores a working edge.
Rasp steel knives from ASC Forge
- Oakridge rasp steel skinner knife with wood handle.
- Stagmere rasp steel skinner knife with stag horn handle.
- Ironcrest rasp steel bull cutter knife, hardened to approximately 60 HRC.
- Handmade rasp steel cowboy hunting knife with pinecone handle.
- Ironvale rasp steel cowboy bull cutter knife with Micarta handle.
Frequently asked questions
What kind of steel is a farrier rasp?
A quality farrier's rasp is made of high-carbon steel, which can be hardened and tempered into a durable knife blade.
Does a rasp steel knife hold an edge?
Yes. A properly heat-treated rasp steel knife holds a good working edge and is quick to resharpen when it dulls.
Why does a rasp knife have teeth on the blade?
The teeth are the original file pattern of the farrier's rasp. Makers leave them on the flats of the blade as a signature look and for added thumb grip.
See all rasp steel, D2 and Damascus options in the ASC Forge cowboy knife collection.