Before you start
- The chisel is sharp. A dull edge crushes fibres instead of severing them and needs force that makes it slip. The sharpening guide covers the edge.
- The work is held. Clamp it or hold it in a vice so that both hands are free for the chisel, as OSHA’s hand-tool guidance advises.
- The line is knifed. A knife line gives the chisel a wall to register against. The measuring and marking guide covers the layout.
- You know which chisel you need. Paring, chopping and mortising call for different blades; see the chisel guide.
Hands and body
In both techniques, the hands have separate jobs (see the plate above). In paring, the rear hand holds the handle and supplies the push, ideally from the shoulder and body rather than the wrist, while the front hand rests on the blade near the edge. That front hand steers the edge and acts as a brake, so the cut stops where you want it to. Paring chisels are made only for this: Narex states that they are pushed by hand, not struck.
In chopping, the chisel is held upright in one hand and struck along the line of its handle with a mallet held in the other. An off-axis blow tips the chisel and drives the edge off the line. Keep both hands behind the edge in every cut.
Which way the bevel faces
With the flat back down, the back rides on the surface as a reference: this is how to pare a surface flat, level the floor of a housing or trim a tenon cheek. With the bevel down, the bevel acts as a fulcrum: raising or lowering the handle steers the edge up or down, which is useful for scooping waste out of a recess and for easing the edge out of a cut before it reaches the far side.
Read the grain first
Wood splits easily along the grain and resists across it, because its cells run lengthways — the Wood Handbook describes most of them as lying with their long axes parallel to the trunk. A chisel is a wedge, so when its edge is driven along the grain it can open a split that runs ahead of the edge and past your line. Across the grain, it cuts.
- Pare downhill. When paring along a surface, cut in the direction in which the fibres run down into the wood ahead of the edge. Cutting the other way, the edge gets under fibres rising toward the surface and lifts them out.
- Chop across before along. When removing waste from a recess, sever the fibres across the grain at the ends first, so that a split along the grain stops at those cuts.
- Take lighter cuts in hard woods. Lie-Nielsen’s own guidance for its chisels is to take lighter cuts in hard woods and not to force the tool.
Paring accurately to a line
Paring to a line
Remove the bulk first
Saw or chop away most of the waste, leaving a small amount to pare. A thin shaving is controllable; a thick one is not.
Set the body behind the chisel
Stand so the push comes from your shoulder along the chisel’s axis, with the front hand on the blade.
Pare in thin shavings, working toward the line
Take a series of light cuts, each a little closer, with the flat back registering on the surface where possible.
Work from the edges toward the middle
Paring right across a narrow edge can break out the far corner. Pare in from each side and meet in the middle.
Make the last cut in the knife line
For the final shaving, drop the edge into the knife line and pare down or across to it, so the finished surface is the line itself.
Check against the reference
Check the surface with a square from the reference face or edge, and take one more fine shaving only where it is needed.
Chopping across the grain to a knife line
Chopping to a shoulder or a dovetail baseline uses the knife line in three stages. The knife line cuts the surface fibres; a small V pared from the waste side gives the chisel a wall to sit against; the final chop puts the chisel’s flat back in that wall.
Chopping across the grain
Knife the line and pare a V
Deepen the knife line slightly, then pare a shallow V from the waste side so that its vertical wall is the knife line.
Chop first in the waste
Set the chisel a little back from the line, bevel toward the waste, and chop down. The first cuts relieve the wood so that the final cut does not have to push waste aside.
Clear the waste in stages
Pare the chopped waste away toward the line, then chop again, going deeper a little at a time.
Make the final chop in the wall
Put the flat face of the chisel in the knife wall, check that it stands upright, and chop to depth.
For a through cut, work from both faces
Chop halfway from one face, turn the work over and finish from the other, so the far face does not break out.
Note— Why chopping directly on the line undercuts
The bevel is a wedge. Driven deep in one blow, it pushes the chisel toward its flat face — toward the part — so the edge runs under the line and the shoulder is undercut. Chopping first in the waste leaves room for the wedge, and the final cut then only removes a thin sliver.
Clearing a housing or recess
A housing, a stopped groove or a recess for hardware uses both techniques together: chopping to set the walls and depth, paring to clear and level the floor.
Clearing a housing across the grain
Knife and saw the walls
Knife both walls, then saw them to depth on the waste side of each line, or chop them to the knife lines as described above.
Chop across the waste
Chop a series of cuts across the waste between the walls, a little shallower than the finished depth. They sever the fibres into short lengths that break out easily.
Clear from both ends, bevel down
With the bevel down, pare the waste out toward the middle from each edge of the board. Working from both edges keeps the far edge from breaking out.
Level the floor, back down
Turn the chisel over and pare the floor with the flat back riding on it, in light cuts, until the floor is flat and at depth.
Check the depth
Check the floor at both edges and in the middle against a gauge line or a depth gauge before fitting the mating part.
Where the floor is wide, a slicing cut helps: pushing the chisel forward while sliding it sideways, or holding it skewed to the direction of travel, draws the edge through the fibres rather than pushing straight into them, and takes less force. End grain in particular pares more cleanly this way.
Avoiding common faults
| Symptom | Cause | Correction |
|---|---|---|
| Crushed, bruised fibres at the line | A dull edge, or a heavy cut taken right at the line | Sharpen; leave only a thin sliver for the final cut |
| Shoulder undercut below the line | Chopping on the line in one deep blow | Chop first in the waste; finish with light cuts in the knife wall |
| A split running past the line | Driving the chisel along the grain before the ends were cut | Chop across the grain first to stop splits |
| Far edge broken out | Paring or chopping right through from one side | Pare from both edges; chop through cuts from both faces |
| Torn surface when paring | Paring against the grain | Reverse the direction and pare downhill |
| Edge wanders off the line | An off-axis mallet blow, or a chisel not held upright | Strike along the handle; check the chisel is vertical before each blow |
For faults in the finished joint, see common technique faults.
Mortising adds levering to chopping, with a heavier chisel built for it; the mortise chisel guide covers the tool and sizing, and the mallet guide matches the mallet to the job.
Sources
The technique is established bench practice, explained here in BenchRoot’s own words; the sources support the statements about wood structure, securing the work and how particular chisels should be used.
- 1.
Alex C. Wiedenhoeft and Thomas L. Eberhardt. Chapter 3: Structure and Function of Wood. USDA Forest Service, Forest Products Laboratory — Wood Handbook, FPL-GTR-282, 2021.
Used for: Most wood cells run with their long axes along the grain, which is why a wedge driven along the grain splits it and one driven across it does not.
- 2.
Hand and Power Tools (OSHA 3080). Occupational Safety and Health Administration, 2002.
Used for: Securing work with clamps or a vice so both hands are free for the tool.
- 3.
Narex Imperial Paring Chisels. Narex, as listed by Infinity Tools.
Used for: Paring chisels are pushed by hand, not struck.
- 4.
1/4" Mortise Chisel. Lie-Nielsen Toolworks.
Used for: Taking lighter cuts in hard woods, and not forcing the tool.
About this tutorial
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