Chisel

What Is a Chisel?

A chisel is a cutting tool with a sharpened edge on one end of a steel blade and a handle on the other. You guide it by hand or strike it with a mallet to remove thin slices or chips of material. The flat side of the blade (the "back") and the angled side (the "bevel") work together to control the cut. Chisels are made in different shapes and steels for wood, masonry, and metal, making them a go-to for precise material removal, fitting parts, and cleanup work in projects.

Key parts:
- Blade: the cutting body of the tool.
- Bevel: the angled, sharpened face.
- Back: the flat face opposite the bevel.
- Shoulder/Tang or Socket: how the blade attaches to the handle.
- Handle/Strike Cap: the grip; some wood chisels include a metal cap for striking.

Common Uses in DIY and Home Improvement

• Woodwork and carpentry: cutting hinge mortises, paring a door edge, trimming dowels and plugs flush, cleaning up joints, fitting moldings.
• Joinery: chopping mortises, refining tenons, squaring routed corners with a corner chisel.
• Masonry: cutting bricks or blocks to size, removing mortar with a plugging chisel, chasing channels for conduit, popping off tiles with a tile chisel.
• Metalwork: cutting rivets, splitting seized nuts, trimming burrs with a cold chisel.
• Repair and demo: scraping old adhesive, lifting flooring transitions, removing excess grout or thinset.

Types of Chisels

Woodworking chisels

• Bench (bevel-edge) chisel: general-purpose wood chisel with beveled sides that reach into tight corners. Common widths: 1/4 in (6 mm) to 1 in (25 mm).
• Paring chisel: longer, thinner blade for fine, hand-powered shaving cuts. Typically used without a mallet.
• Mortise chisel: thick, tough blade for chopping deep mortises. Designed to withstand mallet blows and levering in the cut.
• Firmer chisel: heavier rectangular cross-section; good for general chopping.
• Corner chisel: L-shaped edge that squares inside corners after routing.
• Woodturning chisels/gouges: used on a lathe; specialized profiles (not for mallet use).

Masonry chisels

• Brick set/bolster: wide blade and hand guard for snapping bricks and blocks.
• Plugging (mortar) chisel: narrow blade for raking out mortar joints.
• Point and pitching chisels: for shaping stone.
• Tile chisel/scraper: thin, wide edge for lifting tiles and removing thinset.

Metalworking chisels

• Cold chisel: hardened for cutting cold metal; flat, cape (narrow), round-nose, and diamond-point styles for shaping, grooves, and slots.

Power chisel attachments

• SDS-plus/SDS-max chisel bits: flat, scaling, and tile blades used in rotary hammers for fast removal of masonry, tile, and plaster.

How to Choose the Right Chisel

• Match the material: use wood chisels on wood, masonry chisels on brick/stone, and cold chisels on metal. Cross-using can damage the edge and the work.
• Pick useful widths: for general woodwork, a starter set of 1/4 in, 1/2 in, 3/4 in, and 1 in covers most tasks. A 1 in chisel is handy for common door hinges.
• Steel and edge retention: high-carbon, O1, or A2 steels are common in woodworking; look for good heat treatment and flat backs. For masonry and cold chisels, choose reputable brands and models with a safety hand guard.
• Handle style: wood handles feel great and pair well with a wooden mallet; plastic handles with strike caps tolerate metal hammers and site work.
• Bevel angle: general woodworking chisels are often ground at a 25° primary bevel with a 30° micro-bevel for strength; paring chisels may be 20–25° for easier slicing; mortise chisels often run 30–35°.

How to Use a Chisel Safely and Effectively

• Mark and score: use a sharp knife and square to define your cut. Scoring fibers reduces tear-out in wood.
• Secure the work: clamp your piece or use a bench hook. A steady workpiece is safer and yields cleaner cuts.
• Mind the grain: pare with the grain in wood; take light cuts and flip the chisel as needed to avoid digging in.
• Strike correctly: use a wooden or rubber mallet on wood chisels. Reserve steel hammers for chisels designed for them (e.g., cold chisels, cap-ended chisels).
• Control your body: keep both hands behind the cutting edge, and never push toward your hand. Small, controlled taps beat heavy blows.
• For masonry: wear eye protection and gloves; face chips away from you. Use a club hammer and keep the chisel at a slight angle to guide the fracture.
• For metal: wear safety glasses and hearing protection. Angle the cold chisel around 60° to the work and support the piece firmly in a vise.

Maintenance: Sharpening and Care

• Flatten the back: a dead-flat back is the foundation for a keen edge.
• Grind and hone: establish a primary bevel on a grinder or coarse stone, then hone on waterstones, oilstones, or diamond plates (e.g., 1000/3000/8000 grits). A honing guide helps maintain consistent angles.
• Strop: a leather strop with compound refines the edge and boosts sharpness.
• Rust prevention: wipe clean and add a light coat of oil or wax. Store with edge guards or in a roll to protect edges.
• Reshape mushroomed heads: on cold and masonry chisels, grind off any flared striking heads to prevent chips.

Common Mistakes to Avoid

• Using a wood chisel on masonry or metal (fast way to ruin the edge).
• Prying hard with a thin chisel; use a pry bar instead.
• Striking wood chisels with a steel hammer not designed for them.
• Working with a dull edge; it slips and tears fibers. Sharpen before it gets blunt.
• Ignoring grain direction and taking deep cuts that split the work.
• Not clamping the work or chiseling toward your hand.
• Forgetting eye protection on masonry and metal jobs.

Related Terms

• Mallet: soft-faced hammer for striking chisels without damaging handles.
• Bevel angle: the grind angle that defines edge strength and sharpness.
• Micro-bevel: a small, steeper bevel at the very edge to strengthen it and speed honing.
• Mortise and tenon: a classic wood joint often cut and refined with chisels.
• Honing guide: a jig that holds a chisel at a set angle on a stone.
• SDS-plus/SDS-max: shank systems for rotary hammers that accept chisel bits.

Practical Examples

• Cut a door hinge mortise:
  1) Mark hinge outline with a knife and square.
  2) Set a depth gauge to hinge leaf thickness.
  3) Pare inside the lines with a 1 in bench chisel, working from the scored edge toward the center. Use light mallet taps to reach depth, then smooth with hand pressure.

• Remove a cracked ceramic tile:
  1) Score grout lines and remove grout with a plugging or grout removal tool.
  2) Place a tile chisel at a shallow angle under a corner and tap with a club hammer. Work slowly to lift the tile and scrape away thinset. Wear eye and hand protection.

• Split a rusted nut:
  1) Secure the part in a vise. Position a cold chisel on the flat of the nut and strike to create a groove. Repeat to deepen the split, then turn the nut off.

• Trim a dowel plug flush:
  1) Set the chisel bevel-up and pare across the plug with light pressure, then sand. This avoids tear-out around the hole.