Rasp

How it works

The Nicholson File Company’s treatise of 1878 states the difference between a rasp and a file in the formation of the teeth. In a rasp each tooth is disconnected from the others and is made by a single pointed tool that file makers call a punch. The treatise says the essential requirement is that the teeth be so irregularly intermingled as to produce, in use, the smoothest possible work consistent with the number of teeth in the surface.

Grades of coarseness are set by the number and size of the punched points. The 1878 treatise lists four for rasps, coarse, bastard, second cut and smooth, and associates them with trades: coarse for horse shoers, bastard for carriage makers and wheelwrights, second cut for shoe rasps and smooth for the rasps of cabinetmakers. A review in Fine Woodworking of a hand-cut French rasp says the varied placement of the teeth gives a chatter-free cut, and that the teeth run to the edges and the tapered tip so the rasp can cut into corners.

Anatomy

Face: The toothed surface. On a flat rasp the two faces are flat; on a half-round or cabinet rasp one face is flat and the other convex. Nicholson’s cabinet rasps and files are cut from sections wider and thinner than the half-round.
Teeth: Single points raised with a punch, in the Nicholson description, rather than continuous ridges.
Edges: Cut or left smooth. Nicholson says flat wood rasps have their edges cut coarse and single, while shoe rasps have the edges left safe.
Tang: A spike at the heel for a handle. Nicholson says a file’s length is always measured without the tang; horse and shoe rasps made without a tang are measured over their full length.
Handle: Wooden on the ordinary file or rasp. Nicholson advises forcing the handle well up to the shoulder of the tang.
Point: The tapered end opposite the heel; on hand-cut rasps Fine Woodworking says the teeth extend to it.

Variants

Cabinet rasp: Flat on one face and half-round on the other; Nicholson says 8, 10 and 12 inches are the common lengths and that the cabinet rasp is usually cut smooth.
Wood rasp (flat and half-round): Nicholson’s flat wood rasp has bastard teeth on its sides and coarse single cut edges, and is used by wheelwrights and carriage builders; the half-round wood rasp comes in 10, 12 and 14 inch lengths.
Horse rasp: The tanged or plain rasp of the farrier, made from a heavy rasp section and cut coarse, according to Nicholson.
Shoe rasps: Flat, half-round and oval rasps with edges left safe, used by boot and shoe makers to trim the bottoms of boots and shoes, according to Nicholson.
File-rasp: Nicholson’s flat and half-round “File-Rasps” have a punched rasp cut on one side and a double-cut file face on the other, so the user obtains two cuts of teeth in one tool.
Rifflers: Small bent files and rasps for carvers working wood, metal and stone, sold by Nicholson in 1878 as a set of six, with a form of handle that Nicholson says keeps the unused end out of the way.
Hand-cut (hand-stitched) rasp: A rasp whose teeth are raised one at a time by hand; the French maker Auriou has made them since 1856, according to Fine Woodworking and Popular Woodworking.

Specifications

Length (without tang) · in: 8–12Nicholson gives cabinet rasps in 6 to 14 inches with 8, 10 and 12 most common, and wood rasps of 10, 12 and 14 inches.
Cut (coarseness) · coarse, bastard, second cut, smooth: Nicholson’s four rasp grades; the makers of hand-cut rasps use their own number scales.

Made to

ISO 234-1
ISO 234-2

Safety and care

Safety

Nicholson advises that a file or rasp handle be driven well up to the shoulder, not halfway, and that where heavy pressure is applied the tool be firmly fixed to the handle, because the point of the tang is dangerous if the tool suddenly comes off.

Care

Nicholson says teeth clogged with wood can be loosened by holding the tool in boiling water for a few moments and then carding the debris out.
Nicholson advises cleaning with a file card or file brush before a tool is laid aside, and not throwing files and rasps loose into a drawer with other tools, since only slight rubbing on a hard substance dulls the points of the teeth.

Tips

Irregular teeth cut smoother than regular rows
Nicholson says the points of a rasp are punched so as to be irregularly intermingled, and that the aim is the smoothest work the number of teeth allows. Fine Woodworking says the varied tooth placement of a hand-cut rasp gives a chatter-free cut.1 2
Pick the grade by the trade
Nicholson associates coarse rasps with horse shoeing, bastard with carriage and wheel work, second cut with shoe rasps and smooth with cabinetwork.1
A rasp can be a file on its other face
A file-rasp has a punched rasp cut on one side and a double-cut file face on the other, so that the user can rough with the rasp side and follow with the file side without changing tools.1
Check the edges before working near a corner
Nicholson says flat wood rasps have their edges cut coarse, while shoe rasps have the edges left safe so the edge can be presented to the work without marking an adjoining surface. Fine Woodworking says hand-cut rasps have teeth up to the edges so that they can cut into a corner.1 2
Use the round face for concave work
Nicholson says the convex side of a half-round file shapes concave work and the flat side serves for general purposes, and the cabinet rasp and wood rasp follow the half-round form. Fine Woodworking’s reviewer used the flat-and-half-round cabinet pattern to clean and shape the pierced splat and crest rail of a chair.1 2
Hot water frees baked-in wood
When the teeth are clogged with wood, Nicholson says holding the tool in boiling hot water for a few moments loosens the debris so it can be carded out, and the remaining moisture evaporates quickly from the heat retained in the steel.1

History

Earliest documented

c. 1200–1000 BC (as dated by Disston); seventh century BC for iron rasps

Egypt; Assyrian-period Thebes

A 1922 pamphlet published by Henry Disston & Sons says that small rasps of bronze, 1-1/2 to 2-1/4 inches long and made from sheet bronze punched with holes and rolled into a cone with the burrs outside, have been found in Egypt and are dated by the pamphlet to about 1200 to 1000 BC, and that a similar copper rasp from the Rammesseum is in the University of Pennsylvania museum. It says the Assyrians made a straight iron rasp, an example of which has been found, dated to the seventh century BC, and quotes Flinders Petrie on an iron armourers’ tool set found at Thebes, probably left in 666 BC, which includes a rasp and a file. The pamphlet is a company publication and a secondary account; the original excavation reports and museum records have not been read.1

The rasp is among the oldest abrading tools in metal. The Disston pamphlet reports small sheet-metal rasps from Egypt and an Assyrian iron rasp of the seventh century BC, and quotes Petrie on a rasp and a file in an armourers’ set at Thebes. The pamphlet itself observes that the sheet-metal rasps resemble those made by American Indians in recent times, which it takes as evidence that the form arises independently wherever punched teeth are needed. All of this comes from a company’s popular history, and the dates are the pamphlet’s own.

The Roman evidence is indirect. The Art of Making essay says that Roman sculptors used the rasp as a finishing tool on marble, leaving crisscrossing fine scratches, and that clear rasp marks can be seen over the Column of Trajan. The same essay notes that whether Roman rasps had one end or two is unknown. No Roman rasp itself is cited here.

Nicholson’s treatise of 1878 fixes the rasp as an industrial product with defined grades. It separates the rasp cut from the single and double cuts of files by the disconnected punched tooth, associates each grade with a trade, and describes each tooth as made by a single punch, with the points irregularly intermingled. The same treatise says that elaborate arrangements of cabinet-rasp teeth designed to please particular trades had mostly disappeared, so that by 1878 the cabinet rasp was ordinarily cut smooth and the pattern had been standardized.

The regular, machine-made rasp trades off against the hand-cut one. Fine Woodworking’s reviewer says hand-cut rasps cut more smoothly because the tooth placement is varied, and that the cabinetmaker’s rasp he tested cost about twice a good machine-made tool. Popular Woodworking reports that the French firm Auriou, which had made rasps by hand since 1856, closed in 2007 after a labor dispute, and Fine Woodworking records that production resumed in November 2008 under the name Forge de St Juery. O*NET’s Tools Used table lists rasps in 4 of the 24 occupations mapped to this archive’s trades, among them plumbers, machinists, drywall installers and automotive technicians, rather than carpenters.

Timeline

c. 1200–1000 BC
Small bronze and copper rasps made of punched sheet metal, found in Egypt, according to the Disston pamphlet.1
7th century BC
Assyrian iron rasp, and a rasp and file in a set of iron armourers’ tools at Thebes dated to about 666 BC, according to the Disston pamphlet quoting Petrie.1
Roman imperial period
Rasp marks cover the figures of the Column of Trajan, where the rasp was used to smooth clothing and skin, and appear on the Arch of Trajan at Benevento, according to the Art of Making essay on Roman stone tools.1
1856
The French firm of Auriou is founded and begins to make rasps by hand, according to Fine Woodworking and Popular Woodworking.1 2
1878
The Nicholson File Company of Providence publishes A Treatise on Files and Rasps, defining the rasp cut as separate punched teeth and listing coarse, bastard, second cut and smooth grades.1
1878
Nicholson reports that great ingenuity had formerly gone into arranging the teeth of cabinet rasps in rows, spirals and crescents to suit the preferences of trades, and that such arrangements were rarely found by its day.1
2007
Auriou closes its factory at Saint-Juéry after a labor dispute and the company is handed to liquidators, according to Popular Woodworking.1
2008
Production resumes in November under the name Forge de St Juery, according to Fine Woodworking’s editor’s note.1

Gaps in the record (8)

The Science Museum Group holds a 1926 replica of an ancient Roman rasp or cross file (object 1926-569, credited to Elkington and Company); its record gives no date, findspot or description of the original, so it is not used as evidence.
The Disston pamphlet’s dating of the Egyptian rasps to a “Lisht Dynasty” of about 1200 to 1000 BC uses a dynasty name that is not recognized, and no excavation report or museum record for the Egyptian, Rammesseum or Assyrian rasps has been read.
No Roman rasp or any medieval rasp has been located in a museum record; Roman use is inferred from toolmarks.
Wood-rasp development between the Roman period and 1878 is not sourced; Moxon’s Mechanick Exercises (1703) has no passage on rasps.
The history of machine-cut rasps and of the Stanley Surform and other perforated planes (rasp-like tools) is not sourced.
A retailer’s page gives 1858 rather than 1856 as Auriou’s founding date; retailer pages are not cited here, so the question is not carried into the disputed list.
No standards for rasp grades or tooth counts have been read; standard slugs are guesses.
No independent test of rasps is cited, so buying is null.