Wrench

from Wikipedia, the free encyclopedia
Four wrenches: two open-end wrenches at the rear, two combination wrenches at the front

A wrench is a hand tool for tightening or loosening screws and nuts with certain head shapes (" drive profiles "). In the case of screw heads or nuts, wrenches are placed on the outer surface (on the sides of the screw head), the handle protrudes radially. This is not the case with screwdrivers , which grip the front of the drive profile and whose handle protrudes axially. Usually, however, also be, for example, sockets and the box wrench associated with the wrenches, although their grip (terminal) axially disposed.

The size of a wrench is indicated by the wrench size . With a metric open-end wrench with a wrench size 17, the two parallel “jaws” (theoretically) have a distance of 17 mm. The key size is stamped as a number on the respective side of the key.

The inner profile of a wrench is made with a high quality tool with a process called " broaching ".

Types of wrenches

Open-ended or open-end wrenches

Adjustable wrench with adjustable width

A common type is the open-end or open-end wrench . This can be used to turn hexagon or square screw heads or nuts or also special connecting elements with only two key surfaces arranged parallel to one another. The wrench mouth is usually arranged at an angle of 15 ° to the tool axis in order to make it easier to apply the wrench in confined working spaces. An angle of 75 ° is also common. The size of the opening of the wrench is stamped on the tool.

Most wrenches are of two different sizes, one on each end; the term for this is double open-end wrench. Most of the time, double open-end wrenches are simply called open-end wrenches. There are also open-ended wrenches that have only one handle and one end with a hexagonal socket; these are called single-ended spanners.

A special type of open-end wrench are those with an adjustable wrench size. These are:

Another special form is the open-ended wrench with a ratchet function . The two cheeks of the open-ended wrench are dimensioned so that they can accommodate the ratchet mechanism. The key can be turned freely in one direction and the nut / screw is clamped and turned in the other direction.

Ring spanner

Another wrench is the ring spanner , which can be provided with a ring-shaped hexagonal or double hexagonal profile. It does not slip off as easily as the open-end wrench and allows higher power transmission. However, ring spanners can only be used if you have open access to the screw or nut.

The ring of the wrench encloses the profile of the screw head or the nut as completely as possible in the interests of frictional connection. The ring or the wrench head can be angled, cranked or deep cranked for ergonomic reasons.

The most common shapes are double ring spanners with two different sizes (one on each end) or ring spanners with the same size on both ends, one as a ring spanner and the other as an open-ended spanner.

The open ring spanner is a special form. It is more massive than a normal ring spanner and has a recess so that it can be used in particular with union nuts for line connections, as are common in vehicle brake lines. The open ring spanner is therefore also called a brake line wrench.

A combination of open-end wrenches and ring spanners is called a combination wrench .

Block keys , also called starter (and) block keys , are ring spanners with an arched lever and thin rings, which improve accessibility when there is a lack of space, for example on motor vehicle engine blocks.

Ratchet ring wrench

Ratchet ring wrench

Ring spanners with an integrated ratchet  - i.e. a freewheel  - are used for faster screwing without having to reposition the wrench. Versions with a one-way ratchet are built flat so that they can be used for both screwing directions, often somewhat asymmetrically to the side, which clearly shows the direction of the ratchet, or they have a transverse articulation joint. Angled ratchet ring spanners have a reversible ratchet for both directions and are often riveted to the leg from two layers of sheet metal plus an intermediate layer. Hinged ratchet ring spanners open with one half of the ring and jam by lever action, similar to a pipe wrench .

There are also open ring wrenches.

Pipe wrench

Pipe wrench

One -piece tubular wrenches (tubular socket wrenches) are roughly in the form of a tubular piece, at the ends of which, for example, hexagon socket contours that fit the desired screw heads or nuts are formed. They are actuated with stable pivot pins, possibly multi-stage in diameter, which are inserted into transverse bores. Shaped from drawn tube are thin-walled, axially hollow and thus lighter and more cost-effective. Solid forged ones are more expensive, more stable and not only have two transverse bores along the slimmer center, but often also a long, possibly slightly twisted hexagon for attaching an open-ended wrench.

They are standardized in DIN 896 as form B and are referred to there as "double socket wrenches made of pipe, form B".

Socket wrench

Socket wrench set with ratchet

Flexible use are Socket -sentences with drive parts, such as plug-in handle, wrist, T-handle, offset handle, crank or ratchet (also called "ratchet") in which the actual tool part ( socket , commonly known as a nut or Socket referred) changeable is. The dimensions of the drive parts for forms A to G are specified in DIN 3122. With additional intermediate pieces such as extensions or articulations, you can also operate connecting elements in hard-to-reach places. Compared to tubular socket wrenches, sockets have the disadvantage that the length of the threaded section protruding from a nut to be turned is limited.

The interchangeable tool part is equipped with an internal square that is attached to the matching external square of the drive part. The dimensions of the connecting square are specified in the DIN 3120 or ISO 1174-1 standard. The nominal sizes are 6.3 mm, 10 mm, 12.5 mm, 20 mm and 25 mm, which are also referred to as 1 ⁄ 4 ″, 3 ⁄ 8 ″, 1 ⁄ 2 ″, 3 ⁄ 4 ″ and 1 ″ .

Common and standardized forms of socket wrench inserts are:

Further socket wrench inserts for Torx and locknut wrenches are offered. Special curved hexagonal designs put less strain on the nut edges and are therefore more gentle. There are also variations for slotted, Phillips and Pozidriv screws, especially for attachments with 1 ⁄ 4 ″ square edges on the drive side.

Torque wrenches are used as the drive part for the precise application of a defined torque . These are also equipped with the standardized external square and can therefore accommodate suitable socket wrench inserts.

In addition to the socket wrenches with exchangeable tool parts, there are also socket wrenches with a fixed tool part. Examples for this are:

Socket wrench ( wrench size 5.5) to handle plug
  • Cross wrench in which four socket wrenches are arranged as a right-angled cross
  • Socket wrench screwdriver, a fixed combination of a socket wrench (or nut) with a screwdriver handle

bone

bone

A special wrench for screws and nuts with an external hexagon on the bicycle; hardly used today.

Hook wrench / pinion puller

There is a separate hook wrench for each diameter for tightening locknuts with radial grooves . Articulated hook wrenches cover a certain range of diameters. Wrenches for turning locknuts with two or four grooves on the face - such as on old 5-way racing bike pinions - are called pinion pullers.

Face spanner

Two adjustable and one fixed (for angle grinder) face spanners

For two-hole nuts with face holes, face wrenches are available, with long legs that can be adjusted as with compasses or a joint closer to the pins. With a fixed spacing made of sheet metal with welded pins for turning the hole nut on angle grinders, they are also called flange wrenches, with a slight or strong offset for grinding wheels or high cup wheels . Although angle grinders for discs from 110 to 230 mm in diameter all have the same receptacle with 22.2 mm diameter and 14 mm screw thread, at least three hole spacings are common, nuts with two pairs of holes at different distances are common.

It is less common to find nuts with radial holes in the cylinder jacket of the nut that need a suitably shaped key - for example with an expandable bracket or in the shape of a hook. In its simplest form, it is produced by sharply bending a stiff wire such as a bicycle spoke three times.

Hole nuts are easy to manufacture because of both heavy machinery and, for reasons of space, on motorcycle exhausts, bicycle headsets and fine optics such as in microscopes.

Key with face hole for screws with a central mandrel

Multiple wrenches
Torx screw and key with face hole

The face hole (also the face hole) is a hole in a special wrench for tamper-proof screws and means the counterpart to the mandrel in the profile center of the screw. The face hole drilling occurs most frequently in Torx screwdrivers or Allen keys, which is generally called “Torx TR” or “Inbus TR” (Tamper Resistant (tamper-proof)).

Screwdrivers and wrenches with face bores and the associated screws are usually only available in specialist shops, as they are not typical for normal use.

Usual mouth widths

For metric screw connections, the wrench sizes (SW) listed in the table below are common (see ISO 272 ). The designations M1, M2 etc. stand for the metric ISO threads (ISO 1502 or DIN 13-1). The change from the old to the new standard took place in Germany and Austria in 1992, but in practice it has not yet been fully implemented. The abbreviation “HV connection” means “high-strength, prestressable connection” (common in bridge construction and offshore installations ).

DIN 3110 specifies how much the actual width across flats should be larger than the nominal distance in order to ensure sufficient tolerance while maintaining a good form fit .

Key-width for screw connection Comment / use
4 mm M2
5 mm M2.5
5.5 mm M3
6 mm M3.5
7 mm M4
8 mm M5
9 mm
10 mm M6
11 mm M7 z. B. Older French cars
12 mm
13 mm M8
14 mm old standard for M8
15 mm for axle nuts on bicycles
16 mm M10
17 mm old standard for M10
18 mm M12
19 mm old standard for M12
20 mm
21 mm
22 mm M14 M12 for high-voltage connections
23 mm
24 mm M16
25 mm
26 mm
Key-width for screw connection comment
27 mm M18 M16 for high-voltage connections
28 mm
30 mm M20
32 mm M22 M20 for HV connections,
protective cap hexagon (high pressure) gas cylinder
34 mm Rare
36 mm M24 M22 for HV connections
41 mm M27 M24 for HV connections
46 mm M30 M27 for HV connections
50 mm M33 M30 for high-voltage connections
55 mm M36
60 mm M39 M36 for high-voltage connections
65 mm M42
70 mm M45
75 mm M48
80 mm M52
85 mm M56
90 mm M60
95 mm M64
100 mm M68
105 mm M72
110 mm M76
115 mm M80
130 mm M90
145 mm M100

material

Wrenches are usually made from alloyed tool steel. Tools for use under explosion protection conditions are usually made of brass .

Web links

Commons : Wrench  - Collection of Images
Wiktionary: wrench  - explanations of meanings, word origins, synonyms, translations

The broadcast with the mouse - wrench (ring spanner) youtube.com, published November 17, 2015. Video (14:20)

Individual evidence

  1. ↑ Ratchet wrench in action Online source: youtube
  2. ↑ DIN 3122: Drive parts with external square for hand-operated socket wrench inserts . April 2017.
  3. ↑ DIN 3123: connecting parts with external square for manually operated socket wrench inserts . April 2017.
  4. ↑ DIN 3120: connecting square for hand-operated screwing tools . December 1993.
  5. ↑ DIN 3124: Socket wrench inserts with internal square for screws with hexagon, hand-operated . November 2007.
  6. ↑ DIN 7422: screwdriver bits with internal square . October 2002.
  7. ↑ DIN 2324: Screwdriver bits with internal square for screws with internal multi-point, hand-operated . October 2002.
  8. ↑ Wilhelm Jungermann GmbH: Alloyed tool steels - possible uses , accessed on January 14, 2019