Screw
A screw is an externally
The screw head on one end has a
Most screws are tightened by
The
History
Fasteners had become widespread involving concepts such as
Metal screws used as fasteners were rare in Europe before the 15th century, if known at all.[16] The metal screw did not become a common fastener until machine tools for mass production developed toward the end of the 18th century. This development blossomed in the 1760s and 1770s.[17] along two separate paths that soon converged:[18]
The first path was pioneered by brothers Job and William Wyatt of Staffordshire, UK,[19] who patented in 1760 a machine that one might today best call a screw machine of an early and prescient sort. It made use of a leadscrew to guide the cutter to produce the desired pitch,[19] and the slot was cut with a rotary file while the main spindle held still (presaging live tools on lathes 250 years later). Not until 1776 did the Wyatt brothers have a wood-screw factory up and running.[19] Their enterprise failed, but new owners soon made it prosper, and in the 1780s they were producing 16,000 screws a day with only 30 employees[20]—the kind of industrial productivity and output volume that would later become characteristic of modern industry but which was revolutionary at the time.
Meanwhile, English instrument-maker Jesse Ramsden (1735–1800) was working on the toolmaking and instrument-making end of the screw-cutting problem, and in 1777 he invented the first satisfactory screw-cutting lathe.[21] The British engineer Henry Maudslay (1771–1831) gained fame by popularizing such lathes with his screw-cutting lathes of 1797 and 1800, containing the trifecta of leadscrew, slide rest, and change-gear gear train, all in the right proportions for industrial machining. In a sense he unified the paths of the Wyatts and Ramsden and did for machine screws what had already been done for wood screws, i.e., significant easing of production spurring commodification. His firm would remain a leader in machine tools for decades afterward. A misquoting of James Nasmyth popularized the notion that Maudslay had invented the slide rest, but this was incorrect; however, his lathes helped to popularize it.[citation needed]
These developments of the 1760–1800 era, with the Wyatts and Maudslay as arguably the most important drivers, caused great increase in the use of threaded fasteners.
In 1821 Hardman Philips built the first screw factory in the United States – on Moshannon Creek, near Philipsburg – for the manufacture of blunt metal screws. An expert in screw manufacture, Thomas Lever, was brought over from England to run the factory. The mill used steam and water power, with hardwood charcoal as fuel. The screws were made from wire prepared by "rolling and wire drawing apparatus" from iron manufactured at a nearby forge. The screw mill was not a commercial success. It eventually failed due to competition from the lower-cost, gimlet-pointed screw, and ceased operations in 1836.[23]
The American development of the turret lathe (1840s) and of automatic screw machines derived from it (1870s) drastically reduced the unit cost of threaded fasteners by increasingly automating the machine-tool control. This cost reduction spurred ever greater use of screws.[citation needed]
Throughout the 19th century, the most commonly used forms of screw head (that is,
In the early 1930s American Henry F. Phillips popularized the Phillips-head screw.[27]
Threadform standardization further improved in the late 1940s, when the ISO metric screw thread and the Unified Thread Standard were defined.[citation needed]
Precision screws, for controlling motion rather than fastening, developed around the turn of the 19th century, and represented one of the central technical advances, along with flat surfaces, that enabled the
Manufacture
There are three steps in manufacturing a screw: heading, thread rolling, and coating. Screws are normally made from wire, which is supplied in large coils, or round bar stock for larger screws. The wire or rod is then cut to the proper length for the type of screw being made; this workpiece is known as a blank. It is then cold headed, which is a cold working process. Heading produces the head of the screw. The shape of the die in the machine dictates what features are pressed into the screw head; for example a flat head screw uses a flat die. For more complicated shapes two heading processes are required to get all of the features into the screw head. This production method is used because heading has a very high production rate, and produces virtually no waste material. Slotted head screws require an extra step to cut the slot in the head; this is done on a slotting machine. These machines are essentially stripped down milling machines designed to process as many blanks as possible.
The blanks are then polished[
Types of screws
Threaded fasteners either have a tapered shank or a non-tapered shank. Fasteners with tapered shanks are designed to either be driven into a substrate directly or into a pilot hole in a substrate, and most are classed as screws. Mating threads are formed in the substrate as these fasteners are driven in. Fasteners with a non-tapered shank are generally designed to mate with a nut or to be driven into a tapped hole, and most would be classed as
Sheet-metal screws do not have the chip-clearing flute of self-tapping screws. However, some wholesale vendors do not distinguish between the two kinds.[29]
Wood screw
Early wood screws were made by hand, with a series of files, chisels, and other cutting tools, and these can be spotted easily by noting the irregular spacing and shape of the threads, as well as file marks remaining on the head of the screw and in the area between threads. Many of these screws had a blunt end, completely lacking the sharp tapered point on nearly all modern wood screws.[30] Some wood screws were made with cutting dies as early as the late 1700s (possibly even before 1678 when the book content was first published in parts).[31] Eventually, lathes were used to manufacture wood screws, with the earliest patent being recorded in 1760 in England.[30] During the 1850s, swaging tools were developed to provide a more uniform and consistent thread. Screws made with these tools have rounded valleys with sharp and rough threads.[32][33]
Once screw turning machines were in common use, most commercially available wood screws were produced with this method. These cut wood screws are almost invariably tapered, and even when the tapered shank is not obvious, they can be discerned because the threads do not extend past the diameter of the shank. Such screws are best installed after drilling a pilot hole with a tapered drill bit. The majority of modern wood screws, except for those made of brass, are formed on thread rolling machines. These screws have a constant diameter and threads with a larger diameter than the shank and are stronger because the rolling process does not cut the grain of the metal.[citation needed]
Machine screw
A machine screw is generally a smaller fastener (less than 1⁄4 inch (6.35 mm) in diameter) threaded the entire length of its shank that usually has a recessed drive type (slotted, Phillips, etc.). Machine screws are also made with socket heads (see above), in which case they may be referred to as socket head machine screws.
Hex cap screw
ASME standard B18.2.1-1996 specifies hex cap screws whose size range is 0.25–3 in (6.35–76.20 mm) in diameter. In 1991, responding to an influx of counterfeit fasteners, Congress passed PL 101-592,[35] the "Fastener Quality Act". As a result, the ASME B18 committee re-wrote B18.2.1,[36] renaming finished hex bolts to hex cap screw – a term that had existed in common usage long before, but was now also being codified as an official name for the ASME B18 standard.
Lug bolt and head bolts are other terms that refer to fasteners that are designed to be threaded into a tapped hole that is in part of the assembly and so based on the Machinery's Handbook distinction they would be screws. Here common terms are at variance with Machinery's Handbook distinction.[37][38]
Lag screw
Lag screws (US) or coach screws (UK, Australia, and New Zealand) (also referred to as lag bolts or coach bolts, although this is a misnomer) or French wood screw (Scandinavia) are large wood screws. Lag screws are used to lag together lumber framing, to lag machinery feet to wood floors, and for other heavy carpentry applications. The attributive modifier lag came from an early principal use of such fasteners: the fastening of lags such as barrel staves and other similar parts. These fasteners are "screws" according to the Machinery's Handbook criteria, and the obsolescent term "lag bolt" has been replaced by "lag screw" in the Handbook.[39] However, based on tradition many tradesmen continue to refer to them as "bolts", because, like head bolts, they are large, with hex or square heads that require a wrench, socket, or specialized bit to turn.
The head is typically an external hex. Metric hex-headed lag screws are covered by DIN 571. Inch square-headed and hex-headed lag screws are covered by ASME B18.2.1. A typical lag screw can range in diameter from 4 to 20 mm or #10 to 1.25 in (4.83 to 31.75 mm), and lengths from 16 to 200 mm or 1⁄4 to 6 in (6.35 to 152.40 mm) or longer, with the coarse threads of a wood-screw or sheet-metal-screw threadform (but larger). The materials are usually carbon steel substrate with a coating of zinc
Bone screw
Like aerospace and nuclear power, medical involves some of the highest technology for fasteners where performance, longevity, and quality are reflected in the price. Bone screws tend to be made of stainless steel or titanium, and they often have high-end features such as conical threads, multistart threads, cannulation (hollow core), and proprietary screw drive types (some not seen outside of these applications).
Screw heads
There are a variety of screw head shapes. Some varieties of screw are manufactured with a break-away head, which snaps off when adequate torque is applied. This prevents tampering.
- Pan head
- A low disc with a rounded, high outer edge with large surface area.
- Button or dome head (BH)
- Cylindrical with a rounded top.
- Round head
- A dome-shaped head used for decoration.[40]
- Truss head
- Lower-profile dome designed to prevent tampering.
- Flat head
- Conical, with flat outer face and tapering inner face allowing it to be countersunk into the material. The angle of the screw is measured as the aperture of the cone.
- Oval or raised head
- A decorative screw head with a countersunk bottom and rounded top.[40] Also known as "raised countersunk" or "instrument head" in the UK.[citation needed]
- Bugle head
- Similar to countersunk, but there is a smooth progression from the shank to the angle of the head, similar to the bell of a bugle.
- Cheese head
- Cylindrical.
- Fillister head
- Cylindrical, but with a slightly convex top surface.
- Flanged head
- A flanged head can be any of the above head styles (except the countersunk styles) with the addition of an integrated flange at the base of the head. This eliminates the need for a flat washer.
- Hex head
- Hex shaped, similar to the head of a hex bolt. Sometimes flanged.
Metric
The international standards for metric externally threaded fasteners are ISO 898-1 for property classes produced from carbon steels and ISO 3506-1 for property classes produced from corrosion resistant steels.
Head markings and properties for metric hex-head cap screws[41] | |||||||||
---|---|---|---|---|---|---|---|---|---|
Head marking | Grade, material and condition | Nominal size range (mm) | Proof strength | Yield strength, min. | Tensile strength, min. | Core hardness (Rockwell) | |||
MPa | ksi | MPa | ksi | MPa | ksi | ||||
Class 3.6[42] | 1.6–36 | 180 | 26 | 190 | 28 | 330 | 48 | B52–95 | |
Class 4.6 Low or medium carbon steel |
5–100 | 225 | 32.6 | 240 | 35 | 400 | 58 | B67–95 | |
Class 4.8 Low or medium carbon steel; fully or partially annealed |
1.6–16 | 310 | 45 | 340 | 49 | 420 | 61 | B71–95 | |
Class 5.8 Low or medium carbon steel; cold worked |
5–24 | 380 | 55 | 420 | 61 | 520 | 75 | B82–95 | |
Class 8.8[43] Medium carbon steel; quench and tempered |
Under 16 (inc.) | 580 | 84 | 640 | 93 | 800 | 120 | ||
17–72 | 600 | 87 | 660 | 96 | 830 | 120 | C23–34 | ||
Class 8.8 low carbon Low carbon boron steel; quench and tempered | |||||||||
Class 8.8.3[44] Atmospheric corrosion resistant steel; quench and tempered | |||||||||
Medium carbon steel; quench and tempered |
12–36 | ||||||||
ASTM A325M - Type 3[45][46] Atmospheric corrosion resistant steel; quench and tempered | |||||||||
Class 9.8 Medium carbon steel; quench and tempered |
1.6–16 | 650 | 94 | 720 | 104 | 900 | 130 | C27–36 | |
Class 9.8 low carbon Low carbon boron steel; quench and tempered | |||||||||
Class 10.9 Alloy steel; quench and tempered |
5–100 | 830 | 120 | 940 | 136 | 1,040 | 151 | C33–39 | |
Class 10.9 low carbon Low carbon boron steel; quench and tempered | |||||||||
Class 10.9.3[44] Atmospheric corrosion resistant steel; quench and tempered | |||||||||
Alloy steel; quench and tempered |
12–36 | ||||||||
ASTM A490M - Type 3[45][47] Atmospheric corrosion resistant steel; quench and tempered | |||||||||
Class 12.9 Alloy steel; quench and tempered |
1.6–100 | 970 | 141 | 1,100 | 160 | 1,220 | 177 | C38–44 | |
A2[43] Stainless steel with 17–19% chromium and 8–13% nickel |
up to 20 | 210 minimum 450 typical |
30 minimum 65 typical |
500 minimum 700 typical |
73 minimum 100 typical |
||||
ISO 3506-1 A2-50[citation needed] 304 stainless steel-class 50 (annealed) |
210 | 30 | 500 | 73 | |||||
ISO 3506-1 A2-70[citation needed] 304 stainless steel-class 70 (cold worked) |
450 | 65 | 700 | 100 | |||||
ISO 3506-1 A2-80[citation needed] 304 stainless steel-class 80 |
600 | 87 | 800 | 120 |
Inch
There are many standards governing the material and mechanical properties of imperial sized externally threaded fasteners. Some of the most common consensus standards for grades produced from carbon steels are ASTM A193, ASTM A307, ASTM A354, ASTM F3125, and SAE J429. Some of the most common consensus standards for grades produced from corrosion resistant steels are ASTM F593 & ASTM A193.
Head markings and properties for inch-system hex-head cap screws[43] | |||||||||
---|---|---|---|---|---|---|---|---|---|
Head marking | Grade, material and condition | Nominal size range (in) | Proof strength | Yield strength, min. | Tensile strength, min. | Core hardness (Rockwell) | |||
ksi | MPa | ksi | MPa | ksi | MPa | ||||
SAE Grade 0[48] | Strength and hardness is not specified | ||||||||
SAE grade 1 ASTM A307[49] Low carbon steel |
1⁄4–1+1⁄2 | 33 | 230 | 60 | 410 | B70–100 | |||
ASTM A307 - Grade B[49] Low or medium carbon steel |
1⁄4–4 | 60 minimum 100 maximum |
410 minimum 690 maximum |
B69–95 | |||||
SAE grade 2 Low or medium carbon steel |
1⁄4–3⁄4 | 55 | 380 | 57 | 390 | 74 | 510 | B80–100[50] | |
Greater than 3⁄4 | 33 | 230 | 36 | 250 | 60 | 410 | B70–100[50] | ||
SAE grade 4[51] Medium carbon steel; cold worked |
1⁄4–1+1⁄2 | 100 | 690 | 115 | 790 | ||||
SAE grade 3[49] Medium carbon steel; cold worked |
1⁄4–1 | 85 | 590 | 100 | 690 | B70–100 | |||
SAE grade 5 Medium carbon steel; quench and tempered |
1⁄4–1 (inc.) | 85 | 590 | 92 | 630 | 120 | 830 | C25–34[50] | |
1–1+1⁄2 | 74 | 510 | 81 | 560 | 105 | 720 | C19–30[50] | ||
ASTM A449 - Type 1[49] Medium carbon steel; quench and tempered |
1–1+1⁄2 (inc.) | 74 | 510 | 105 | 720 | C19–30 | |||
1+1⁄2–3 | 55 | 380 | 90 | 620 | Brinell 183–235 | ||||
SAE grade 5.1[52] Low or medium carbon steel; quench and tempered |
No. 6–1⁄2 | 85 | 590 | 120 | 830 | C25–40 | |||
SAE grade 5.2[52] Low carbon martensitic steel; quench and tempered |
1⁄4–1 | 85 | 590 | 120 | 830 | C26–36 | |||
ASTM A449 - Type 2[52] Low carbon martensitic steel; quench and tempered |
C25–34 | ||||||||
or | ASTM A325 - Type 1[49] Medium carbon steel; quench and tempered |
1⁄2–1 (inc.) | 85 | 590 | 92 | 630[51] | 120 | 830 | C24–35 |
1–1+1⁄2 | 74 | 510 | 82 | 570[51] | 105 | 720 | C19–31 | ||
[53] | ASTM A325 - Type 3[49] Atmospheric corrosion resistant steel; quench and tempered |
1⁄2–1 | 85 | 590 | 92 | 630[51] | 120 | 830 | C24–35 |
1–1+1⁄2 | 74 | 510 | 82 | 570[51] | 105 | 720 | C19–31 | ||
ASTM A354 - Grade BC[49] Medium carbon alloy steel; quench and tempered |
1⁄4–2+1⁄2 (inc.) | 105 | 720 | 109 | 750[51] | 125 | 860 | C26–36 | |
2+1⁄2–4 | 95 | 660 | 99 | 680[51] | 115 | 790 | C22–33 | ||
SAE grade 7 Medium carbon alloy steel; quench and tempered |
1⁄4–1+1⁄2 | 105 | 720 | 115 | 790 | 133 | 920 | ||
SAE grade 8 Medium carbon alloy steel; quench and tempered |
1⁄4–1+1⁄2 | 120 | 830 | 130 | 900 | 150 | 1,000 | C32–38[50] | |
ASTM A354 - Grade BD[54] | 1⁄4–2+1⁄2 (inc.) | 120 | 830 | 130 | 900[54] | 150 | 1,000 | C33–39 | |
2+1⁄2–4 | 105 | 720 | 115 | 790[54] | 140 | 970 | C31–39 | ||
SAE grade 8.2[50] Medium carbon boron martensitic steel; fully kilned, fine grain, quench and tempered |
1⁄4–1 | 120 | 830 | 150 | 1,000 | C33–39 | |||
ASTM A490 - Type 1[49] Medium carbon alloy steel; quench and tempered |
1⁄2–1+1⁄2 | 120 | 830 | 130[51] | 900 | 150 minimum 170 maximum |
1,000 minimum 1,200 maximum |
C33–38 | |
[53] | ASTM A490 - Type 3[49] Atmospheric corrosion resistant steel; quench and tempered | ||||||||
18/8 Stainless Stainless steel with 17–19% chromium and 8–13% nickel |
1⁄4–5⁄8 (inc.) | 40 minimum 80–90 typical |
280 minimum 550–620 typical |
100–125 typical | 690–860 typical | ||||
5⁄8–1 (inc.) | 40 minimum 45–70 typical |
280 minimum 310–480 typical |
100 typical | 690 typical | |||||
over 1 | 80–90 typical | 550–620 typical |
Tools
Part of a series on |
Screw drive types |
---|
Slotted |
Cruciform |
External polygon |
Internal polygon |
Hexalobular |
Three-pointed |
Special |
The hand tool used to drive in most screws is called a
Modern screws employ a wide variety of
Screw threads
There are many systems for specifying the dimensions of screws, but in much of the world the ISO metric screw thread preferred series has displaced the many older systems. Other relatively common systems include the British Standard Whitworth, BA system (British Association), and the Unified Thread Standard.
ISO metric screw thread
The basic principles of the ISO metric screw thread are defined in
The nominal diameter of a metric screw is the outer diameter of the thread. The tapped hole (or nut) into which the screw fits, has an internal diameter which is the size of the screw minus the pitch of the thread. Thus, an M6 screw, which has a pitch of 1 mm, is made by threading a 6 mm shank, and the nut or threaded hole is made by tapping threads into a hole of 5 mm diameter (6 mm − 1 mm).
Metric hexagon bolts, screws and nuts are specified, for example, in International Standards ISO 4014, ISO 4017, and ISO 4032. The following table lists the relationship given in these standards between the thread size and the maximum width across the hexagonal flats (wrench size):
ISO metric thread | M1.6 | M2 | M2.5 | M3 | M4 | M5 | M6 | M8 | M10 | M12 | M16 | M20 | M24 | M30 | M36 | M42 | M48 | M56 | M64 |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Wrench size (mm) | 3.2 | 4 | 5 | 5.5 | 7 | 8 | 10 | 13 | 16 or 17 | 19 | 24 | 30 | 36 | 46 | 55 | 65 | 75 | 85 | 95 |
In addition, the following non-preferred intermediate sizes are specified:
ISO metric thread | M3.5 | M14 | M18 | M22 | M27 | M33 | M39 | M45 | M52 | M60 |
---|---|---|---|---|---|---|---|---|---|---|
Wrench size (mm) | 6 | 21 | 27 | 34 | 41 | 50 | 60 | 70 | 80 | 90 |
Bear in mind that these are just examples and the width across flats is different for structural bolts, flanged bolts, and also varies by standards organization.
Whitworth
The first person to create a standard (in about 1841) was the English engineer Sir Joseph Whitworth. Whitworth screw sizes are still used, both for repairing old machinery and where a coarser thread than the metric fastener thread is required. Whitworth became British Standard Whitworth, abbreviated to BSW (BS 84:1956) and the British Standard Fine (BSF) thread was introduced in 1908 because the Whitworth thread was too coarse for some applications. The thread angle was 55°, and the depth and pitch varied with the diameter of the thread (i.e., the bigger the bolt, the coarser the thread). Spanners for Whitworth bolts are marked with the size of the bolt, not the distance across the flats of the screw head.
The most common use of a Whitworth pitch nowadays is in all UK
British Association screw thread
British Association (BA) screw threads, named after the British Association for Advancement of Science, were devised in 1884 and standardised in 1903. Screws were described as "2BA", "4BA" etc., the odd numbers being rarely used, except in equipment made prior to the 1970s for telephone exchanges in the UK. This equipment made extensive use of odd-numbered BA screws, in order—it may be suspected—to reduce theft. BA threads are specified by British Standard BS 93:1951 "Specification for British Association (B.A.) screw threads with tolerances for sizes 0 B.A. to 16 B.A."
While not related to ISO metric screws, the sizes were actually defined in metric terms, a 0BA thread having a 6 mm diameter and 1 mm pitch. Other threads in the BA series are related to 0BA in a geometric series with the common factors 0.9 and 1.2. For example, a 4BA thread has pitch mm (0.65 mm) and diameter mm (3.62 mm). Although 0BA has the same diameter and pitch as ISO M6, the threads have different forms and are not compatible.
BA threads are still common in some niche applications. Certain types of fine machinery, such as moving-coil meters and clocks, tend to have BA threads wherever they are manufactured. BA sizes were also used extensively in aircraft, especially those manufactured in the United Kingdom. BA sizing is still used in railway signalling, mainly for the termination of electrical equipment and cabling.
BA threads are extensively used in Model Engineering where the smaller hex head sizes make scale fastenings easier to represent. As a result, many UK Model Engineering suppliers still carry stocks of BA fasteners up to typically 8BA and 10BA. 5BA is also commonly used as it can be threaded onto 1/8 rod.[55]
Unified Thread Standard
The Unified Thread Standard (UTS) is most commonly used in the
Mechanical classifications
The numbers stamped on the head of the bolt are referred to the grade of the bolt used in certain application with the strength of a bolt. High-strength steel bolts usually have a hexagonal head with an
Ultimate tensile strength is the tensile stress at which the bolt fails. Tensile yield strength is the stress at which the bolt will yield in tension across the entire section of the bolt and receive a permanent set (an elongation from which it will not recover when the force is removed) of 0.2%
Mild steel bolts have property class 4.6, which is 400 MPa ultimate strength and 0.6*400=240 MPa yield strength. High-strength steel bolts have property class 8.8, which is 800 MPa ultimate strength and 0.8*800=640 MPa yield strength or above.
The same type of screw or bolt can be made in many different grades of material. For critical high-tensile-strength applications, low-grade bolts may fail, resulting in damage or injury. On SAE-standard bolts, a distinctive pattern of marking is impressed on the heads to allow inspection and validation of the strength of the bolt.[57] However, low-cost counterfeit fasteners may be found with actual strength far less than indicated by the markings. Such inferior fasteners are a danger to life and property when used in aircraft, automobiles, heavy trucks, and similar critical applications.[58]
The Machinery's Handbook describes the distinction between bolts and screws as follows:
A bolt is an externally threaded fastener designed for insertion through holes in assembled parts, and is normally intended to be tightened or released by torquing a nut. A screw is an externally threaded fastener capable of being inserted into holes in assembled parts, of mating with a preformed internal thread or forming its own thread, and of being tightened or released by torquing the head. An externally threaded fastener which is prevented from being turned during assembly and which can be tightened or released only by torquing a nut is a bolt. (Example: round head bolts, track bolts, plow bolts.) An externally threaded fastener that has thread form which prohibits assembly with a nut having a straight thread of multiple pitch length is a screw. (Example: wood screws, tapping screws.)[59]
This distinction is consistent with
Old
See also
- Syndesmotic screw – Type of screw
- Tap and die – Tools to create screw threads
- Threaded rod – Rod with ridges wrapped around it
- Threading (manufacturing) – Process of creating a screw thread
- Wall plug – Insert for screws
References
Citations
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- ^ See:
- Henry F. Phillips and Thomas M. Fitzpatrick, "Screw," U.S. Patent no. 2,046,839 (filed: January 15, 1935; issued: July 7, 1936).
- Henry F. Phillips and Thomas M. Fitzpatrick, "Screw driver," U.S. Patent no. 2,046,840 (filed: January 15, 1935; issued: July 7, 1936).
- ^ Rybczynski 2000, p. 104.
- ^ "Faster Superstore catalog of sheet-metal screws and self-tapping screws".
- ^ a b White, Christopher. "Observations on the Development of Wood Screws in North America" (PDF).
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- ^ "Making 18th c wood screws".
- ^ "Iron Age, Volume 44". 1889.
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- ^ "Mechanical properties of bolts, screws, and studs according DIN-ISO 898, part 1" (PDF). Retrieved 2009-06-06.
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- ^ a b "ASTM F568M - 07". 2007. Retrieved 2009-06-06.
- ^ a b c d "Metric structural fasteners". Archived from the original on 1999-04-21. Retrieved 2009-06-06.
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- ^ a b "ASTM A490M - 09". 2009. Retrieved 2009-06-06.
- ^ "Mechanical Methods of Joining". Retrieved 2009-06-06.
- ^ a b c d e f g h i "Grade Markings: Carbon Steel Bolts". Retrieved 2009-05-30.
- ^ a b c d e f "Hardware, bulk — Technical information". Retrieved 2009-05-30.
- ^ a b c d e f g h "ASTM, SAE and ISO grade markings and mechanical properties for steel fasteners". Retrieved 2009-06-06.
- ^ a b c "Fastener identification marking" (PDF). Retrieved 2009-06-23.
- ^ a b Other markings may be used to denote atmospheric corrosion resistant material
- ^ a b c "FastenalTechnicalReferenceGuide" (PDF). Retrieved 2010-04-30.
- ^ "Thread Systems" (PDF). Thread Check. Archived (PDF) from the original on Feb 2, 2023.
- ISBN 0-07-048511-9.
- ^ "How to Recognize Metric and SAE Bolts Archived 2018-09-25 at the Wayback Machine", Chilton DIY, Retrieved April 26, 2016.
- ^ "SAE Standards for Mobility Knowledge and Solutions". SAE International. Retrieved 2023-02-20.
- ^ Oberg et al. 2000, p. 1492.
- ^ "screw". Cambridge Dictionary of American English. Cambridge University Press. Archived from the original on 2008-12-06. Retrieved 2008-12-03.
- ^ "screw". allwords. Retrieved 2008-12-03.
- ^ "bolt". Merriam Webster Online Dictionary. Retrieved 2008-12-03.
- ^ "bolt". Compact Oxford English Dictionary. Oxford. Archived from the original on January 6, 2005. Retrieved 2008-12-03.
- ^ "bolt". Cambridge Advanced Learner's Dictionary. Cambridge University Press. Archived from the original on 2008-12-06. Retrieved 2008-12-03.
- ^ "How to use tools and make repairs". Dyke's Automobile and Gasoline Engine Encyclopedia. A.L. Dyke. 1919. p. 701. Retrieved 2009-01-13.
- ^ "What Every Member of the Trade Community Should Know About: Distinguishing Bolts from Screws". An Informed Compliance Publication (2011-02 ed.). Washington, D.C., USA: U.S. Customs and Border Protection Agency (CBP). July 2012.
General and cited references
- Bickford, John H.; Nassar, Sayed (1998). Handbook of bolts and bolted joints. CRC Press. ISBN 978-0-8247-9977-9.
- Colvin, Fred Herbert; Stanley, Frank Arthur (1914). American Machinists' Handbook and Dictionary of Shop Terms (2nd ed.). McGraw-Hill.
- Hallowell, Howard Thomas Sr (1951). How a Farm Boy Built a Successful Corporation: An Autobiography. Jenkintown, Pennsylvania, USA: Standard Pressed Steel Company. OCLC 521866.
- Huth, Mark W. (2003). Basic Principles for Construction. Cengage Learning. ISBN 1-4018-3837-5.
- Oberg, Erik; Jones, Franklin D.; Horton, Holbrook L.; Ryffel, Henry H. (2000). Machinery's Handbook (26th ed.). New York: Industrial Press Inc. ISBN 0-8311-2635-3.
- OCLC 462234518. Various republications (paperback, e-book, braille, etc).
- Ryffel, Henry H.; et al. (1988). Machinery's Handbook (23rd ed.). New York: Industrial Press. ISBN 978-0-8311-1200-4.
- ISBN 0-87938-406-9.
External links
- How the World Got Screwed
- NASA-RP-1228 Fastener Design Manual
- Imperial/Metric fastening sizes comparison
- "Hold Everything", February 1946, Popular Science article section on screws and screw fastener technology developed during World War Two
- How to feed screws and dowels
- American Screw Sizes Chart – TPOHH Fasteners