Claw hammer

How it works

The user swings the hammer from the handle so that the face meets the nail head squarely. CCOHS advises striking with the face parallel to the surface being struck and avoiding glancing blows, and notes that hammers with beveled faces are less likely to chip or spall.

To draw a nail, the user slips the V of the claw under the nail head and rocks the hammer back on the curve of the claw, so that the handle acts as a lever arm and the head as the fulcrum. Petrie, writing in 1917, describes the carpenter’s hammer or claw hammer as the hammer “for drawing nails.”

The head must stay on the handle. Parton’s account of the hammer-maker David Maydole records that carpenters valued his hammers because the head and handle were so united that the head would not fly off, and Ernest Estwing’s 1924 patent sets out to remove the objections to a separate head and handle by drop-forging both in one piece.

Anatomy

Face: The striking surface. CCOHS recommends discarding any hammer with a mushroomed or chipped face.
Claw: Two curved, tapering prongs with a V-shaped slot between them for gripping a nail under its head. CCOHS recommends discarding a hammer with cracks in the claw or eye.
Eye: The hole through the head that receives the handle. In the adze-eye form described by Parton, the eye is lengthened so the handle has a firmer hold of the head.
Handle: Wood, or steel forged in one piece with the head. Estwing’s 1924 patent fitted the forged steel handle with riveted scales or grips, of wood in the illustrated example.
Wedge: On a wooden handle, the means of tightening the handle in the eye; Parton says a well-seasoned, well-wedged adze-eye handle will not let the head fly off.

Variants

Adze-eye claw hammer: The head carries a lengthened eye, after the manner of an adze, for a longer and tighter grip on the handle; credited by Parton to David Maydole.
One-piece forged steel claw hammer: Head and handle drop-forged from one piece of steel, with grips fitted to the handle; patented by Ernest O. Estwing (US 1,578,502, 1926).
Continental claw hammer: Petrie observed in 1917 that the claw hammer of about four centuries earlier was made exactly as on the Continent in his own day. The Science Museum Group holds German examples of the seventeenth and eighteenth centuries.

Specifications

Head weight · oz or lb (head without handle): Sargent & Co.’s 1869 catalog lists Maydole’s cast steel hammers by number and by weight of the head without the handle, from 7 oz to over 1 lb.
Face diameter relative to struck tool · mm: For striking another tool, CCOHS recommends a face about 12 mm (0.5 in) larger than the face of the tool being struck.

Made to

ASME B107.400

Safety and care

Safety

Wear safety glasses or goggles, or a face shield over safety glasses or goggles (CCOHS).
Do not strike one hammer with another, or strike other hard metal objects, stones or concrete; misuse can chip the striking face and cause serious injury (CCOHS).
Do not strike with the side or cheek of the hammer (CCOHS).
Do not use a hammer whose handle is loose, cracked, splintered or loosely attached to the head (CCOHS).
Use hammers with electrically insulated handles for work on or around exposed energized parts, and de-energize and lock out where possible (CCOHS).

Care

Replace loose, cracked or splintered handles (CCOHS).
Discard a hammer with a mushroomed or chipped face or with cracks in the claw or eye (CCOHS).

Tips

Put a block under the head for long nails
When a long nail is being pulled, the manual says to place a block of wood under the hammer head for better leverage.1
Seat the claw fully before pulling
The claw is slipped under the nail head as far as it will go, to prevent bending the head up, and the handle is then pulled to a vertical position to withdraw the nail.1
Hold near the end of the handle
The manual says the proper hold on any hammer is near the end of the handle, which is shaped to grip without slipping, and gives the best control and impact with the least effort. A nail should be struck squarely and on center to keep the hammer from glancing off.1
Match the swing to the nail
Small nails take light blows almost entirely from the wrist. Heavy blows for large nails come from the wrist, forearm and shoulder.1

History

Earliest documented

Roman period

Roman world (findspots not stated in the text)

Petrie, cataloging ancient tools in 1917, states that the carpenter’s hammer or claw hammer, for drawing nails, is a Roman type, illustrated by two examples (his nos. 108 and 109), the second of which resembles a modern farrier’s hammer. The earliest excavated claw-hammer head located for this entry with a stated context is medieval: an iron head with incomplete flat claws from a thirteenth-century context at Rhuddlan, Denbighshire, now in Museum Wales.1 2

The claw hammer combines two tasks that the nail creates: driving it and removing it. Petrie, surveying ancient tools in 1917, found that the true hafted hammer appears in Europe only just before iron came into general use, and placed the claw hammer for drawing nails among Roman types. The form then persisted with little change. A thirteenth-century head from Rhuddlan in Museum Wales already has flat claws, and Petrie judged a claw hammer of about four centuries before his time to be made exactly as Continental claw hammers still were. The Science Museum Group’s German claw hammers of the seventeenth and eighteenth centuries fall within the same tradition.

For most of that history the weak point was the joint between head and handle. The Rhuddlan head had an unusually deep socket that did not hold, and someone drove a nail through the eye to keep the loose handle in place. Parton’s account of David Maydole, a New York blacksmith, turns on the same fault. Maydole showed Parton older hammers that tried to solve it with an iron rod run through the handle and a nut at the end, or with head and handle made of one piece of iron. Maydole’s answer was the adze-eye: a longer eye that gave the handle a firmer hold and could be wedged tight.

Maydole’s hammers moved from a blacksmith’s order book into the national hardware trade. Parton reports that a New York tool dealer left a standing order for as many as Maydole could make, and that the business grew to employ 115 men. By 1869 Sargent & Co. of New York were cataloging Maydole’s cast steel hammers by number and by head weight. Parton also records that Maydole tried machinery and abandoned it, hammering and tempering each head by hand over charcoal.

The twentieth-century answer to the same problem was to remove the joint altogether. Ernest Estwing’s patent, filed in 1924, describes axes, hammers and hatchets drop-forged in one piece, then normalized, annealed and hardened, so that the many objections to the conventional head-and-handle construction disappear. The company says it was the first to manufacture and sell hammers forged in one piece of solid steel. The forged handle needed grips; the patent shows wooden scales riveted to the sides, and the company dates its leather handle to the 1930s.

The claw hammer remains one of the most widely listed tools in occupational data. O*NET’s Tools Used table lists claw hammers among the tools of 106 occupations. Its hazards are those of any striking tool used on hardened objects. CCOHS warns against striking another hammer or other hard metal, which can chip the face and cause serious injury, and recommends eye protection.

Timeline

Roman period
Claw hammers for drawing nails are in use, according to Petrie’s 1917 catalog of ancient tools (his nos. 108 and 109).1
1200s
An iron claw-hammer head is lost at Rhuddlan, Denbighshire, in a feature associated with a drying kiln of the thirteenth century; X-rays show incomplete flat claws and a nail driven through the eye to hold the now-lost wooden handle.1
c. 1500s
A claw hammer of about four centuries before 1917 is, in Petrie’s description, made exactly as claw hammers were on the Continent in his day (his no. 112).1
1600s
A German wrought-iron claw-hammer head and a German claw hammer of this century enter the Science Museum Group collection (objects 1931-290 and 1953-431).1 2
1700–1800
A large claw hammer of iron and wood, probably German, is dated to this period by the Science Museum Group (object 1953-432).1
mid-1800s
David Maydole, a village blacksmith in New York State, develops the adze-eye hammer, whose lengthened eye holds the handle tightly; Parton reports Maydole saying he had made hammers for twenty-eight years when they met.1
1869
Sargent & Co. of New York list Maydole’s cast steel hammers by number and head weight in their hardware catalog.1
1869
Vaughan begins business, with an improved post auger; the company later expands into hammers and other hand tools.1
1923
Ernest O. Estwing establishes the Estwing Manufacturing Company in Rockford, Illinois, according to the company.1
1926
Estwing is granted US Patent 1,578,502 (filed 1924) for axes, hammers and hatchets with head and handle drop-forged in one piece; it is reissued in 1927 as Re. 16,820.1 2
1930s
Estwing introduces its leather handle, according to the company.1
2005
An Estwing hammer is added to the Industry and Manufacturing collection of the Smithsonian’s National Museum of American History, according to the company.1

Where the sources disagree

Who first made hammers with head and handle in one piece?

Estwing was the first company to manufacture and sell hammers with the head and handle forged from one piece of solid steel.1
Estwing Manufacturing Company
Before Maydole’s improvements in the nineteenth century, one of the older hammers he kept was wholly of iron, the head and handle being all of one piece; Parton describes such devices as clumsy.1
James Parton, from David Maydole’s own collection and account

Gaps in the record (5)

Petrie’s Roman claw hammers (nos. 108 and 109) are not given findspots or dates in his text; no museum record of a Roman claw hammer has yet been located and read.
Parton does not name Maydole’s village or date the adze-eye hammer; no patent or dated document for it has been located.
The Science Museum Group records for the two claw hammers of object 1979-816/20 and the old claw hammer stamped with a crown and C (1929-238) give no date, so they are not used in the timeline.
No published test or failure data has been located to judge handle materials or head designs, so buying is null.
ASME B107 striking-tool standard text was not read; the standard slug is unverified.