Pipe wrench

How it works

The fixed (heel) jaw is forged with the handle. The movable (hook) jaw is carried on a threaded shank and is set to the pipe with an adjusting nut. The hook jaw is not rigid: it is held in a housing with springs that allow it to pivot slightly, and the RIDGID use guide says this permits the proper gripping and ratcheting action of the wrench.

When the handle is pulled in the working direction, the pipe pushes the hook jaw and its frame so that the two sets of teeth close on the pipe; the harder the pull, the tighter the grip. Stillson’s 1869 patent describes this directly: the handle is pressed forward and, turning on its pivot, shuts the jaws together and firmly clasps the pipe. When the pressure is removed the pipe is released and the wrench can be moved back for a new bite.

Stillson’s patent also describes a stop: the front end of the lower part of the frame strikes the shank and arrests the motion of the frame, which it says prevents the jaws from crushing the pipe. The RIDGID guide gives a related warning for modern wrenches: the teeth dig into the material, which marks the pipe, and high forces can crush or oval thin-wall pipe.

Anatomy

Handle: Forged or cast; RIDGID lists ductile iron and aluminum handle versions. A hanging hole at the end lets the wrench be hung up.
Heel jaw (fixed jaw): Forged with the handle and fitted with hardened, serrated teeth. Thewes’s 1925 patent describes a hardened jaw secured in a slot at the head by a pin.
Hook jaw (movable jaw): Carries the second set of teeth and is set with the adjusting nut; it pivots slightly in the housing.
Adjusting nut: Runs on the threaded shank of the hook jaw. Thewes’s 1925 patent also provides a scale on the shank so that the distance between the jaws can be read against the nut.
Housing and springs: Contains the springs that hold the hook jaw in position and let it pivot. Stillson’s 1869 patent uses a spring to hold the frame in its working position.

Variants

Heavy-duty straight: The standard form, with jaws in line with the handle; RIDGID describes it as suitable for all forms of pipe work.
End pipe wrench: Jaws at the end of the handle at a right angle, for working close to a wall or parallel to it (RIDGID).
Offset pipe wrench: Jaws offset from the handle axis for tight spots and awkward angles (RIDGID).
RapidGrip: A wrench with a V-shaped hook; RIDGID instructs that the work piece be centered in the V and touch both sides.
Compound leverage wrench: A wrench head used with a chain and trunnion that multiplies leverage, intended by RIDGID for seized joints.
Aluminum- or ductile-iron-handle wrench: Alternative handle materials offered by RIDGID.
Pipe tongs: The earlier form: two levers with a hooked jaw moved by an adjusting screw, as in James R. Brown’s 1858 patent.

Specifications

Nominal wrench length · in: 6 to 60 in. in the RIDGID seriesRIDGID’s Chart 1 pairs each wrench length with a suggested pipe range and a maximum pipe size, for example 10 in. for 1/4 to 1 in. pipe (maximum 1-1/2 in.) and 18 in. for 1 to 2 in. pipe (maximum 2-1/2 in.). The chart is for RIDGID wrenches.
Maximum hardness of work · BHN: 325 (RIDGID)The RIDGID guide says not to use the wrench on material harder than 325 BHN, because the teeth must penetrate the stock to grip.
Jaw capacity · in or mm: Maximum pipe size is a manufacturer figure; no independent standard has been sourced.

Safety and care

Safety

The RIDGID guide prohibits handle extensions (“cheaters”), powered or mechanical devices to turn a pipe wrench, and striking the wrench with a hammer to break a fitting loose, because impact and overload can damage the wrench or the teeth and cause injury.
A bent or twisted handle shows the wrench has been overloaded; RIDGID says it must not be straightened and the wrench must be removed from service.
Do not use the wrench on hard, square, hexagonal or other non-round stock; it may slip or the teeth may chip. Do not use it near flame or high heat, which can soften the teeth.
OSHA states that wrenches must not be used when the jaws are sprung to the point that slippage occurs.
Do not modify, grind or weld the wrench, and support the work piece so that the pipe cannot fall or shift (RIDGID).

Care

Clean the wrench before use so that the handle and gripping surfaces are dry and free of oil and grease; clean the jaws with a wire brush so the teeth are clean and sharp (RIDGID).
Replace jaws when the teeth are worn enough to cause slippage, and use genuine service parts (RIDGID).
Lubricate moving parts and joints as needed with light oil, wipe off the excess and store the wrench in a dry place (RIDGID).
Inspect for cracks, nicks, deformation, discoloration from heat, and bent or twisted handles; on chain wrenches, check the chain for separated links (RIDGID).

Tips

Keep a gap between the hook jaw’s shank and the pipe
RIDGID says that on a wrench of any size a gap must be kept between the shank of the hook jaw and the work piece, so that both sets of teeth do the gripping. If the shank touches the work the grip is greatly reduced, the wrench can slip, and the hook jaw may fail; a wrench too small for the work shows this fault.1
Square the wrench to the pipe and adjust with the nut
RIDGID instructs that the hook position be set by turning the adjusting nut and that the wrench be held square to the pipe, not at an angle. On the RapidGrip pattern the pipe is centered in the V so that it touches both sides.1
Pull the wrench and use body weight at the vise
RIDGID says pulling a wrench generally gives better control than pushing in unexpected circumstances. With horizontal pipe in a pipe vise at waist height it is often most effective to use body weight to tighten or loosen, keeping both feet on the ground.1
Choose the wrench length from the pipe size
Each wrench length has a suggested range and a maximum pipe size. RIDGID’s chart pairs, for example, the 14 in. wrench with 1/2 to 1-1/2 in. pipe and the 24 in. wrench with 1-1/2 to 2-1/2 in. pipe, with a larger maximum for each.1
The wrench ratchets: release pressure to reset the bite
Stillson’s patent describes a jaw that grips when the handle is pressed forward and releases when pressure is taken off, so the wrench can be moved back and re-set without being removed. The Matheson museum describes this as a semi-ratcheting action in which the wrench can also be swung in a full circle without losing its grip while pressure is held.1 2
For a seized joint use a larger or compound-leverage wrench
Where more torque is needed RIDGID directs the user to a larger wrench or a compound leverage wrench, whose trunnion is mounted on the pipe close to the threads with its shank pointing toward them. It also suggests breaking the connection another way, such as heat or hammering on the joint (not on the wrench), or taking the system apart at the next connection and loosening the joint in a vise.1
Check that the hook jaw floats
The hook jaw should move smoothly when the nut is turned, and the springs in the housing should let it pivot slightly. RIDGID gives this as a pre-use check because it is what allows the proper grip and ratcheting action.1

History

Earliest documented

1858 (documentary)

Boston, Massachusetts

James R. Brown of Boston was granted US Patent 22,157 on 30 November 1858 for pipe-tongs: a lever pair with a hooked jaw that an adjusting screw moves toward or away from a tooth to fit a pipe. William Kearney of Union, New Jersey, was granted US Patent 30,579 on 6 November 1860 for a wrench for pipes and stud-bolts. The Matheson History Museum blog dates an earlier “Screw Wrench for Grasping Cylindrical Forms” to 1849 but gives no patent number, and the original has not been read here.1 2 3

The pipe wrench answered a problem that a nut wrench cannot solve. The Matheson History Museum blog notes that water, steam and gas lines were assembled from threaded iron pipe, that each joint had to be leak-proof and so needed considerable torque, and that nut wrenches could not get a grip on round objects. Wrenches made for round work appeared in the middle of the nineteenth century. Two United States patents show the earliest forms: Brown’s 1858 pipe-tongs, with a hooked jaw adjusted by a screw, and Kearney’s 1860 wrench for pipes and stud-bolts. The Matheson blog dates a still earlier screw wrench for cylindrical forms to 1849.

Stillson’s 1869 patent described a wrench whose jaws carry teeth raking in opposite directions and whose movable jaw is joined to the fixed jaw by a pivoted frame. His specification states how it works: pressing the handle forward shuts the jaws on the pipe, a stop prevents the jaws from crushing it, and removing the pressure releases it. He claimed ease of adjustment and certainty of operation as its advantages. His patents of 1870 and 1872 refined the screw and the frame; the 1872 patent lets the frame swing so that the angles of the jaw faces change.

The design was a commercial success. Alloy Artifacts identifies Walworth as the original maker and says the royalties made a small fortune for the inventor, and it argues that the Stillson patent may have been the most important tool patent of the nineteenth century. A collector’s page reports that Stillson was paid over $80,000 in royalties in his lifetime. Alloy Artifacts adds that by 1895 a catalog page was needed to show the many competing designs, that the Stillson pattern remained the leading pipe wrench for more than fifty years, and that by 1908 the patent had expired and many makers sold Stillson-pattern wrenches.

The next change came from Ohio. The North Ridgeville Historical Society says William Thewes, working from the Stillson wrench, proposed a slanted jaw that would give more gripping power on pipe of varying sizes and shapes, applied for a patent in 1922, and that the Ridge Tool Company began producing the wrench in early 1923 under the name RIDGID. Thewes’s 1925 patent describes a wrench that can be adjusted and operated by one hand, a casing that holds the threaded jaw shank by friction, a scale on the shank to read the distance between the jaws, and jaw teeth built to withstand maximum usage. His 1929 patent describes jaws that move longitudinally and also angularly so that they bite into the pipe when pressure is applied. Alloy Artifacts says Ridgid-style wrenches became a commodity after the Thewes patents expired.

The modern pipe wrench is a family of tools. The RIDGID use guide lists straight, end, offset, RapidGrip and compound-leverage wrenches, with ductile iron and aluminum handles, and sets limits that follow from the way the tool works: work no harder than 325 BHN, round stock only, no extensions. O*NET’s Tools Used table lists pipe wrenches in 6 of the 24 occupations mapped to this archive’s trades.

Timeline

1849
A US patent for a “Screw Wrench for Grasping Cylindrical Forms” is issued, according to the Matheson History Museum blog (no patent number given).1
1858
James R. Brown of Boston is granted US Patent 22,157 for pipe-tongs with a screw-adjusted hooked jaw (30 November).1
1860
William Kearney of Union, New Jersey, is granted US Patent 30,579 for a wrench for pipes and stud-bolts (6 November).1
1869
Daniel C. Stillson of Charlestown, Massachusetts, is granted US Patent 95,744 for a pipe wrench with toothed fixed and adjustable jaws joined by a pivoted frame (12 October).1
1870
Stillson is granted US Patent 107,304 for an improved screw wrench (13 September).1
1872
Stillson is granted US Patent 126,161 for a pipe wrench whose frame swings so that the angle between the jaw faces changes (30 April).1
1882
Caleb C. Walworth of Boston is granted US Patent 262,263 for a pipe wrench in which the force passes through the body of the wrench rather than through the guide piece of the movable jaw (8 August).1
1895
The Strelinger catalog devotes a page to illustrations of pipe wrench designs, according to Alloy Artifacts.1
1908
An August 1908 Walworth advertisement in Machinery urges buyers to “Ask for the GENUINE Stillson”; the patent had expired and other makers offered Stillson-pattern wrenches, according to Alloy Artifacts.1
1922–1923
William O. Thewes applies for a patent in 1922 on a pipe wrench with slanted jaws; the Ridge Tool and Machine Company begins production of the Thewes wrench in early 1923 under the name RIDGID, according to the North Ridgeville Historical Society.1 2
1925
Thewes is granted US Patent 1,552,091 (1 September) and US Patent 1,565,338 (15 December), both assigned to the Ridge Tool Company.1 2
1929
Thewes is granted US Patent 1,727,623 for a wrench whose jaws move longitudinally and also angularly to bite into the pipe (10 September).1

Where the sources disagree

Was the Stillson wrench the first wrench for pipe?

No. Pipe-gripping wrenches were patented before Stillson: a screw wrench for cylindrical forms in 1849 (no number given), pipe-tongs in 1858 (US 22,157) and a wrench for pipes in 1860 (US 30,579).1 2 3
Matheson History Museum blog; US Patents 22,157 and 30,579
The Stillson design was the original of the modern pipe wrench and its patent may have been the most important tool patent of the nineteenth century.1
Alloy Artifacts

Where and when was the Ridge Tool Company founded?

Thewes’s patent application was made in 1922; the company was formed with the purchase of the Schwartz-Van Wormer Company’s building, land and machinery in North Ridgeville, and production of the Thewes wrench began in early 1923.1
North Ridgeville Historical Society
Ridge Tool was founded as the Ridge Tool Machinery Company in 1922 in Elyria, Ohio, per an April 1922 trade notice, and used the Ridgid brand by 1923.1
Alloy Artifacts
Thewes’s patents, filed in 1923 and 1924, give North Ridgeville, Ohio, as his residence and as the assignee’s address.1 2
US Patents 1,565,338 and 1,552,091

Where was Walworth’s company located?

Boston, Massachusetts.1 2
Alloy Artifacts; Caleb C. Walworth’s 1882 patent
Cambridge, Massachusetts.1
Mental Floss
Stillson himself is described as of Charlestown, Massachusetts, in his patents.1 2 3
US Patents 95,744, 107,304, 126,161

Gaps in the record (7)

The 1849 patent for a screw wrench for cylindrical forms is known here only from the Matheson blog; its number and text have not been located.
The filing date of Stillson’s 1869 patent is not stated in the readable text of the patent and has not been confirmed.
Stillson’s $80,000 royalty figure comes from a collector’s web page and has no primary source here.
RIDGID’s own company timeline page refused access from this machine, so Ridge Tool’s founding date and place rest on a local historical society and a collector’s reference site.
The patent that resulted from Thewes’s 1922 application has not been identified; the earliest Thewes patents located here were filed in 1923 and 1924.
No standard or independent specification for pipe wrenches has been located; a retailer’s guide says they fall outside ASME B107, which is unconfirmed, so standards is empty.
No independent test data has been found, so buying is null.