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How to use a mortice chisel without bruising the ends

Updated: 23 October 2026

A heavy blow is what bruises the ends of a first mortice. You use a mortice chisel by clamping the wood, honing the edge, striking the hoop with a mallet, and levering the chip inside the hole. This page does not rank the listings on the [mortise chisel comparison](/hub/hand-tools/mortise-chisel), and it does not set up a drill press. Peter F. set the sequence from published hand-tool methods and UK safety notes checked on 22 October 2026. There is no filmed joint. If a bevel-edge chisel might do this, read [mortice chisel or bevel-edge chisel](/hub/hand-tools/mortise-chisel/sub/mortise-chisel-vs-bevel-edge) first. A qualifying purchase can earn us a commission at no extra cost to you.

A heavy blow is what bruises the ends of a first mortice. You use a mortice chisel by clamping the wood, honing the edge, striking the hoop with a mallet, and levering the chip inside the hole.

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Narex Narex Richter 13 mm

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On this page
  1. 1.Set the wood and the edge
  2. 2.Chop and lever
  3. 3.Depth and the through mortice
  4. 4.When this method is the wrong tool

Set the wood and the edge

Clamp the piece so a mallet blow cannot bounce it. A bench vice often holds a stile at a bad angle, so older accounts prefer a morticing block or a cramp. Mark the mortice with a knife, because a pencil line disappears under the first chip. Tape on the blade, set to the tenon or to about two-thirds of the stock on a stopped mortice, is the depth mark. Hone first. Several of the 31 United Kingdom reviews on the Narex set say the factory grind still needed work. A blunt edge crushes the fibres. The Eyecare Trust tells DIY readers that chips from chiselling call for protection to BS EN 166, and that ordinary spectacles do not count. Strike the hoop or ferrule with a wooden joiner's mallet. A steel hammer splits a beech handle.

Chop and lever

Start inside the knife lines, a few millimetres in from each end, with the bevel facing the way you are travelling. The bevel is the fulcrum. Levering on the finished end dents the line you still need. Paul Sellers cites about 35°. The Richter bullet says a 25° front bevel and a 30° to 35° secondary for hardwood. Those are two published figures, not an angle measured here. Take a chip, step forward, and lever the waste while wood is still left at both ends. If the mortice grows wider than the chisel, you are tipping it. If it sticks, ease it. The taper on the Narex set is side relief. Twisting a stuck chisel bruises the walls. Leave the knife lines until the hole is at depth.
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Depth and the through mortice

On a stopped mortice, stop when the tape meets the surface, then pare the bottom flat. One last heavy blow drives the corner past the tenon. On a through mortice, chop from the first face to a little past halfway, clear the chips, turn the wood, and meet it from the other face. Blowing out the far side leaves a ragged mouth a shoulder will not hide. Pare the ends back to the knife lines only when the depth is there. A mouth that is square on one face and drunk on the other usually means the second face had no fresh knife line, or the wood moved. Check both mouths before you cut the tenon. On 18 mm stock the depth mark should match the tenon you have sawn, not a 145 mm blade from a listing bullet.

When this method is the wrong tool

This sequence is for a few mortices at the bench. A run of identical square holes is a machine job, and only if something clamps the sleeve. That choice, including a hand caught in a bit, is on the hollow mortise chisel page. Do not chuck a square-hole bit in a cordless drill mid-cut. Stop and get a joiner for a fire door, a stair or a joist, or if a cut has already slipped. The Provision and Use of Work Equipment Regulations 1998 apply to work equipment, not a one-off job at home, and they do not make a sleeve safe in a hand drill. Use the mortice chisel for the socket and a bevel-edge for the shoulder. Width, if you have not bought yet, is the buying guide. The part people skip is the hone.

Common questions

Do I hit a mortice chisel with a hammer or a mallet?
Use a wooden joiner's mallet on the hoop or the ferrule. A steel hammer dents and splits the beech handles these listings describe. The Narex bullets name ferrules and a hoop. They do not name a hammer. If the handle is already mushroomed, stop and sort the handle before you take the bruise into the next mortice.
Where do I start the first blow?
Inside the knife lines, not on them, with the bevel pointing toward the rest of the mortice. Leave a few millimetres of waste at each end so the levering happens on that waste. You pare to the line last, when the hole is deep enough. Starting on the line and levering backwards is how the end becomes wider than the chisel.
How do I stop the mortice getting wider than the chisel?
Keep the blade vertical and lever on the bevel, in the middle of the hole, rather than twisting or prising against the side wall. A chisel that is wider at the edge than behind it, which is the taper these Narex bullets describe, will still cut a wide mouth if you tip it. Check with a square after the first few chips, not after the mortice is finished.
What angle should the edge be?
There is no single legal angle. One published hand method cites about 35°. The Richter amazon.co.uk bullet cites a 25° front bevel and a 30° to 35° secondary for hardwood. Hone a secondary bevel you can feel catching, and keep the primary intact. A blunt 25° edge still crushes. Neither figure was measured on these listings.
How do I know the depth?
Put tape on the blade at the depth of the tenon, or at the depth you marked on the face of the wood. Stop when the tape meets the surface. On a through mortice, chop from both faces so you are not driving out the far side. Guessing from the handle length is how a stopped mortice breaks through a 20 mm rail.
When should I stop and get a joiner?
Stop if the work is a fire door, a stair or a joist, if you cannot clamp the wood, or if the chisel has already slipped and damaged the face. A hollow bit you cannot hold still is the same kind of stop, and it belongs with the machine page rather than with another mallet blow. A one-off furniture mortice in a cramp, with eye protection and a sharp edge, is the job this method is for.

Related pages

Chisel honing guide

Mortise chisel

Best mortice chisel for a first joint or a full set

Mortice chisel sizes: width, pattern and first tool

Hollow mortise chisel or a hand chisel and the clamp

Mortice chisel vs bevel edge when the hole is deep

Sources

Public UK sources and amazon.co.uk listing files. Checked on 22 October 2026.

  1. HSE: PUWER overview (retrieved 22.10.2026)
  2. Consumer Rights Act 2015, goods contract rights (retrieved 22.10.2026)
  3. HSE: using the right type of PPE (retrieved 22.10.2026)
  4. Eyecare Trust: eye protection for DIY (retrieved 22.10.2026)
  5. UK Workshop: recommendations for mortise chisels (retrieved 22.10.2026)
  6. UK Workshop: mortise chisels (retrieved 22.10.2026)
  7. Toolnut: Narex mortice chisel (retrieved 22.10.2026)
  8. Workshop Heaven: Narex Richter mortice chisels (retrieved 22.10.2026)