A cold chisel is a heavy, usually elongated steel chisel used for cutting into stone, concrete and metal. The name comes from working metal cold: unlike forging, the material is not heated first.
Characteristics
- Length — typically 20 to 40 cm. Longer gives more reach and keeps your hand further from the hammer; shorter gives more control on fine work.
- Material — chrome vanadium steel, hardened at the cutting edge and left tougher at the striking head, so the tip stays sharp and the head does not shatter.
- Driving — struck by hand with a club hammer; SDS-shank versions are also made for breakers.
Types
- Flat chisel — a broad straight edge, for cutting out surfaces, tiles and plaster.
- Point chisel — a pointed tip that concentrates the force on one spot, for breaking concrete or starting an opening.
- Plugging chisel — a narrower version with a fine tip, for chasing and raking out joints.
- With a hand guard — a rubber or plastic disc around the shaft that shields your hand if you miss, and damps vibration at the same time.
- Non-sparking — copper alloy versions for work around flammable materials.
Using it safely and effectively
- Always wear eye protection. Concrete and stone fragments fly off at speed. This is the single most important rule in chiselling work.
- Grind the mushroom off the head. Repeated striking upsets the head and forms a sharp lip that can shatter off. Grind it away regularly — at low speed and cooled, so you do not draw the temper.
- Angle of attack. Set the chisel at an angle of roughly 30 to 45 degrees to the surface and work inward from a free edge. Striking square on from above greatly increases the chance of uncontrolled breakage.
- Work in small bites. Especially on masonry that has to stay standing: light blows along the joints rather than lifting out large lumps.
- Use the right hammer. A club hammer with enough mass; a light claw hammer bounces and damages both the tool and your wrist.
- Never use it as a wedge or pry bar. Side loading snaps the hardened tip.
Related terms
- Chisel
- Chasing chisel
- Bush hammer
- Breaker
- Club hammer
- Claw hammer
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