Wood chisel

How it works

The edge is a wedge ground on one face. Petrie notes that the prehistoric Egyptian chisels sloped on both sides, but that from the First Dynasty the single slope, which he calls the true chisel edge, was preferred.

The chisel is used in two ways. Moxon described both in 1703: the former is driven with the mallet, set just outside the scribed line with its bevel outward so that it breaks off the chips, and the paring chisel, which must have a very fine edge, is not struck but pushed with the shoulder against the end of the handle to pare away what the former left. CCOHS likewise advises making finishing or paring cuts with hand pressure alone.

A chisel also levers out the waste it cuts, which is why mortise chisels are thick. Petrie traces this to the first dynasties of Egypt, where the weakness of the square bar for levering chips out of mortises led to deepening it. Moxon describes the mortise chisel as narrow but much thicker than other chisels, so that it can endure heavier blows, and ground to a very broad bevel.

Anatomy

Blade: Steel, flat on the back; bevel-edged blades have their long edges beveled as well.
Edge (bevel): Ground on one face only in the true chisel edge described by Petrie.
Tang or socket: The means of holding the handle: a tang is a spike driven into the handle; a socket is a cone formed on the blade that receives the handle. Petrie dates both to the same period of the Bronze Age.
Bolster and ferrule: A shoulder on a tanged blade and a metal collar on the handle that resist the tang splitting the handle. Petrie describes a Roman tang mortise chisel from the Fayum with handle and ferrule complete.
Handle: Wood or plastic. Stanley’s 1932 socket chisels used hickory handles with protecting leather washers; CCOHS says only heavy-duty or framing chisels with solid or molded handles are made to be struck with a steel hammer.

Variants

Firmer chisel: A general-purpose bench chisel. Shannon’s 1873 catalog lists English firmer chisels by Wm. Butcher and Isaac Greaves and American socket firmer chisels by Crossman.
Paring chisel: A long, thin chisel for hand pressure only; Moxon’s paring chisel is never struck. The Science Museum Group holds a 3/4-inch bevel-edged paring chisel from Charles Nurse & Co.’s 1926 range.
Mortise chisel: Narrow and thick, for chopping deep square holes with a mallet (Moxon). The Science Museum Group holds a Hearnshaw Bros. sash mortice chisel of 1926.
Socket framing chisel: A heavy socket chisel for framing, listed by Shannon in 1873.
Butt chisel: A short chisel; Stanley’s 1932 No. 750 bevel-edge butt chisel was about 9 1/2 to 10 1/2 inches overall.
Skew chisel (skew former): An edge ground at an angle, which Moxon says joiners seldom used except for cleaning acute angles.

Specifications

Blade width · in: Stanley’s 1932 socket chisels were offered in widths up to 2 inches.
Overall length · in: Stanley 1932: No. 720 firmer about 13 inches, No. 740 pocket 12 inches, No. 750 butt about 9 1/2 to 10 1/2 inches.

Made to

BS 3066

Safety and care

Safety

Keep hands and body behind the cutting edge, and clamp the work so it cannot move; do not hold the work in one hand while chiseling with the other (CCOHS).
Use a wooden or plastic mallet with a large striking face; only heavy-duty or framing chisels with solid or molded handles are made to be struck with a steel hammer (CCOHS).
Do not use a wood chisel as a pry or wedge, or on metal (CCOHS).
Wear eye protection where particles may be released from the workpiece or during sharpening (CCOHS).
Check the stock for knots, staples, nails and screws before chiseling (CCOHS).

Care

Keep the edge sharp; a dull chisel is harder to control and takes more effort (CCOHS).
Redress a mushroomed face or chipped edge with a file or whetstone, and do not use a grinder on heat-treated tools (CCOHS).
Store chisels in a slotted cloth or plastic roll in a drawer or tray (CCOHS).

Tips

Bevel down to remove stock, bevel up to finish
The manual states that rough cuts are made with the bevel side down and smooth finishing cuts with the bevel side up.1
Stop 1/8 inch short of the line
The cut is started about 1/8 inch from the guide line, working toward the waste area to protect the edge, and the last 1/8 inch is removed with the chisel and mallet to complete the job. Guide marks are checked often to prevent overcutting.1
Read the grain and secure the work
Before cutting, the grain is examined and the wood placed securely in a vise so that the cut runs with the grain and the wood cannot move in any direction.1
Take small cuts with short blows
The manual calls for short, rapid mallet blows to control the depth and length of cut, and for small, thin cuts, which prevent breaking or splitting of the work.1

History

Earliest documented

prehistoric Egypt (Naqada period)

Naqada, Egypt

Petrie classifies the bare metal chisel, held without any handle, as the earliest type. It occurs in the first period of prehistoric Egypt on a very small scale as a kind of hand graver, sometimes sharpened at both ends, proving that it was held by the middle; his examples come from graves at Naqada. By the First Dynasty a pad of wood was put on the flattened end for end pressure, and the single-slope edge was preferred.1

The chisel is one of the oldest metal tools, and its early history is a history of how it was held. Petrie, classifying the Egyptian collection at University College London in 1917, made the method of holding the main division: bare metal, tang in handle, and handle in socket. The bare bar came first. Predynastic Egyptian chisels were small hand gravers held by the middle; by the First Dynasty a wooden pad was fitted to a flattened end so the tool could be pushed or struck, and the single-bevel edge was preferred to the double slope.

The work of Egyptian carpentry shaped the blade. Petrie explains that the chisel was used not only to cut but to lever out the waste, especially in the many mortises cut to join planks edgeways, and that the weakness of the square bar led to a deeper section for strength. He describes this deep chisel with a double slope as peculiar to Egypt. The mortise chisel of Moxon’s joinery in 1703 answers the same need: a narrow blade made much thicker than other chisels so it can stand heavier blows of the mallet.

The tang and the socket arrived together. Petrie places the first true tangs and the first socketed chisels in the great Bronze Age hoard of Bologna, which he dates to perhaps 900 BCE, and notes that tools rarely survive because they were not buried in graves as weapons were. British Late Bronze Age finds include both forms: socketed chisels from the Cardiff flood plain in Museum Wales and a tanged chisel in the London Museum. The tang chisel with a ferrule was established by Roman times, as Petrie’s complete example from the Fayum shows.

The two fixings survived side by side into the industrial catalogs. J. B. Shannon’s 1873 Philadelphia catalog sold English firmer chisels by Butcher and Greaves next to Crossman’s socket firmer and socket framing chisels, and Stanley in 1932 was still selling socket chisels whose blade and socket were forged in one piece with no welded joint. The handle had to withstand the mallet, and Stanley fitted leather washers to protect its hickory handles. CCOHS today distinguishes ordinary chisels, to be struck only with a wooden or plastic mallet, from heavy-duty or framing chisels made to take a steel hammer.

The joiner’s set of chisels described by Moxon has changed little in its basic types. O*NET’s Tools Used table lists wood chisels among the tools of 26 occupations, 16 of them in construction and extraction, installation and maintenance, and production occupations.

Timeline

Predynastic
Small bare-metal chisels, used as hand gravers and sometimes sharpened at both ends, are buried in graves at Naqada, Egypt.1
First Dynasty
A pad of wood is fitted to the flattened end for end pressure, the single-slope chisel edge is preferred, and the deepened bar of the mortise chisel begins.1
probably Second Dynasty
A small bronze chisel of this date, given by Flinders Petrie, enters the Science Museum Group collection (object 1924-373).1
c. 1370 BCE
A bronze chisel is lost at Amarna, Upper Egypt; it is excavated in the 1921–22 season and is now in the Science Museum Group collection.1
c. 900 BCE
Tang chisels and socketed chisels first appear together in the bronze hoard (fonderia) of Bologna, which Petrie dates to perhaps 900 BCE.1
Late Bronze Age
Socketed bronze chisels are deposited on the flood plain between the Ely and Taff rivers at Cardiff (found 1928; Museum Wales 30.130/3–6), and a copper-alloy tanged chisel enters the London Museum’s prehistoric collection (A10754).1 2 3
Roman period
A tang mortise chisel with handle and ferrule complete is used at Wushym in the Fayum; Petrie classes flat iron chisels as mostly Roman.1
1703
Moxon’s Mechanick Exercises describes the joiner’s formers, paring chisel, skew former, mortise chisel and gouge, and how each is used.1
1873
J. B. Shannon of Philadelphia lists English firmer and paring chisels by Wm. Butcher and Isaac Greaves alongside Crossman’s socket firmer, socket framing and corner chisels.1
1926
Charles Nurse & Co. of London sell a 3/4-inch bevel-edged paring chisel with an octagonal box handle and a Sheffield sash mortice chisel; both are now in the Science Museum Group collection.1 2
1932
Stanley catalogs its Nos. 720 firmer, 740 pocket and 750 butt socket chisels, with blade and socket in one piece and no welded joint, in electric-furnace tool steel with hickory handles.1

Gaps in the record (5)

No conflicting accounts of the chisel’s origin or of the dates of the tang and socket have been found among the sources read; Petrie’s dating of the Bologna hoard to perhaps 900 BCE has not been checked against later archaeological dating.
The Museum Wales and London Museum records give the period only as Late Bronze Age, without absolute dates; British Museum records of socketed chisels could not be read from this machine.
The Shannon catalog text does not say whether the Butcher and Greaves firmer chisels were tanged; that is not assumed here.
No standard for woodworking chisels has been read; the standard slug is a guess.
No independent test of edge retention or steel quality has been located, so buying is null.