In the standard chart, a bolts tensile strength is represented as grade radial marks on top of the bolts head. Fine-threaded drywall ones work best with metal studs, while coarse-threaded ones work with wood studs. For custom products in a specific application, Online CNC design also serve your needs. Metric Bolt Size Chart Thread Pitch Conclusion Introduction to Bolts, Nuts and Washers A Bolt is a cylindrical object with a hexagonal (sometimes square) head on one end and threads (fully or partially) on the other end. For nuts the size dimensions used are simply diameter and pitch. A common type is the pan head with a round head. The standard metric bolt diameters are specified in the standard ISO 898-1 Tables 4 and 5. Its length is measured from its tip to the point where its shank meets the head. Because of their great holding strength, bolts have a broad range of use compared to other fasteners. [1] The charts below show which are interchangeable between metric and standard, aka imperial or. ), for this chart you can just drop the 'M' from the front and add an extra at the back (M3 = 3mm, M4 = 4mm.). The imperial system uses inches when getting the length from the tip to where the head rests and the diameter. Youll find two extra columns: one for Outside Eye Diameter and one for Inside Eye Diameter. SAE and metric nuts and bolts will need to be used with the corresponding wrench sizes. The boltchart provides both US and metric stud sizes. Metric Fasteners; Socket Screws; Hex Bolts; Nuts; . Hex head ones are an exception to this rule, which means you need to measure from the bottom of the head. In the metric chart, tensile strength is written as class numbers on a bolts head. 24 mm. Fraction . Hex bolts are designed with a hexagonal head that to be driven by a wrench and external machine threads, maybe partially threaded or fully threaded. When you get into the smaller dia sizes the pitch goes pretty small. Youll most likely use coarse threaded bolts, which have a lower thread count. Keep in mind that when I say bolt size, I refer to the bolts shank, not the head. If you spot another number next to the class, for instance, 10.8, this number is called the yield strength. The yield strength describes the level of stress it can take before it is bent past the point of no return to its original shape. There are actually up to four pitch . For example, an M10x1.5 (coarse) thread has a 1.5mm pitch, while an M10x1.25 (fine) thread has a 1.25mm pitch. Sheet metal screws secure sheet metal. For example, an M3 bolt with a medium fit would have a 3.4 mm clearance hole. Push the bolt into the holes on the gauge and find the smallest hole the bolt will fit into. This isnt the only thing thats different, though! dimensional data and technical information shown on the fastenerdata website is in the public domain and has not been acquired through the standards agencies, it has been completed and compiled by fastenerdata and is for guidance only; where discrepancies are found they are subject to change without notice. THREAD (BOLT THREADS) A raised, helical rib or ridge around the interior or exterior of a cylindrically shaped object. The length of a metric bolt is measured and defined in exactly the same way as imperial bolts (fasteners). Some require you to pre-drill, while others are self-tapping. Functional diameter is a measure of the ability to assemble the thread. However, it would take a longer time to remove or install. You can use it in metal and wood. Based on the results, the metric bolt size chart shows that you can fit an M14 bolt into the 13mm hole. US Bolts - Tensile Strength and Proof Loads - Tensile strength and proof loads SAE bolts. Note: Not all sizes are available in ALL . Ones with a flat or oval head should be measured from the top to the tip. Metric bolt sizes are available in a range of diameters, from as small as 2mm to as large as 100mm or more. Bolt heads are usually hexagonal, square, or circular. If there are four thread gaps in a one-inch length, the thread pitch would be 0.250 inches (one inch / 4 thread gaps = 0.250 inches). See Our Other FREE Downloadable Resources In the metric system, we use pitch instead of thread spacing. Standard Thread Size Tap Drill Size (Inches) Clearance Drill Size (Inches) #0-08 #56 (0.046) 1/16 (0.062) #1-64 #53 (0.059) #49 (.073) #1-72 #53 (0.059) #49 (.073) . Different Types of Roof Sheathing and Their Benefits. Facebook; Twitter; Instagram; Pinterest; Back. As an Amazon Associate we earn from qualifying purchases. Use a ruler or a measuring tape to get the most accurate measurement. The size of a bolt is determined by the diameter of the bolt's shank (separate from the bolt head). For example, 4.0 x 50 means the screw has a diameter of 4 mm and a length of 50 mm. According to their construction, eyebolts can be classified as the forged and bent eye. The thread count in the imperial system ranges from 35 to 40 threads per inch. If the packaging has measurements indicated in the metric system, the first digit represent the diameter. The M5 screw size has a diameter of 5mm. Keep in mind that when purchasing ones with measurements that are listed in the metric system, the initial number is the diameter. This International Standard specifies selected sizes for screws, bolts and nuts in the diameter range from 1 mm to 64 mm of ISO general purpose metric screw threads (M) having basic profile according to ISO 68-1. Lag boltLag bolts, also known as lag screws, one of the toughest fasteners are extremely sturdy. It can save you from buying the wrong type, leading to unnecessary expenses and wasted time and effort. Lay-over charts for quickly identifying diameter, thread count and other US fastener dimensions. However, heres a quick overview from the chart: Heres the standard & metric screw size chart you need to help you find the right products at the shop! Whether youre working on a DIY project or a construction job, what you need is a proper and basic understanding of how to use a chart for bolt sizes. For metric bolts, head size is measured in millimeters. But neither the external threads of the bolt nor the internal threads of the nut are exactly .500 in diameter. Gauge = (Head diameter in sixteenths of an inch X 2) 2. The square drive (Robertson drive) and star drive (Torx) have a head that minimizes camming out. Diameter: the width of the bolt shank, the bolt head is not included. In our case, only a 1/2 in. Take the diameter of the bolt, and multiply by 1.5. These are the M Profile limiting Dimensionings . The measurement should start wherever the head rests. Some sex bolts have knurled barrels to allow one-sided assembly. Metric & standard bolt screw sizes are determined by length and thread count. Still, there are some oddly shaped bolts out there. The diameter in the imperial system is represented in either fraction of an inch or a gauge number. Take the length of a flat head from the tip to the top of the head. It can even cause a failed project. Metric nut comparison. The diameter and length of the stud and bolt are covered in flange standard ASME B16.5 & B16.47. The shank has no threads. For any other types that are not countersunk, measure from the flat underside to the tip. 1. Kindly say, the Metric Bolt Size Chart Pdf is universally compatible with any devices to read bolts types and sizes metric imperial bolt dimensions web aug 18 2020 the size of a metric bolt is specified using pitch diameter and length in millimeters for example in m8 1 0 20 the m means the metric thread designation the digit 8 Sizing for nuts will appear as diameter and pitch. Deck screws are for fencing and decks, but they can also be used for similar outdoor projects. For round-headed ones that are countersunk, start measuring where the countersunk and the oval top meet in the middle. Dont choose rain chains before reading this + DIY options. The bolt chart provides both US and metric stud sizes. Regular lawn mower maintenance promotes lawn health. For instance, you can see the following in the chart: 1 1/8 converts to a 28.575 mm socket. The M10 screw size has a diameter of 3/16 inches. Do not use these values for standard metric internal thread design. However, metric bolt head size is measured in millimeters. FASTENERS 101 Fastener Reference Tables Conversions, Hardness, Thread Pitch, Tensile Strength The tables below are provided as a general guide to help you better understand metric and imperial measurements. Always refer to project specifications and consult an engineer to ensure that your application is appropriate. Remember that the standard bolt size equivalent is an approximation, not a direct equivalence. Youll most likely need to know the bolt head diameter to determine the wrench size to tighten or loosen the bolt. To measure screw size, we take its diameter. A bolt size chart describes its size based on its proportions. metric-size-chart-hex-bolt Created Date: 2/16/2017 12:47:07 PM . | CNCLATHING, Compare Different Fasteners: Difference Between Bolt, Screw, Rivet and Nut | CNCLATHING, What are UNF Threads and UNC Threads? In the metric system, its the distance between two threads in millimeters. It evolved through a series of amendments in the said act. Several kinds of bolts exist, which include Hex bolts, J bolts, T bolts, Anchor bolts, and Flange bolts. How to Tighten Your Door Handle Quick & Easy! Brass, nylon, stainless steel, steel, aluminum, and titanium are a few of the materials used in fabricating this type. Most of us are more familiar with standard measurements. The diameter of an M6 screw is 6mm. It may take additional time to adjust if you are already comfortable with the imperial system. The M12 is even wider and can shoulder heavier loads. Generally, the first column of a well-made comprehensive chart like the ones below or a size chart pdf contains the nominal bolt sizes. US Screw size conversion chart: Screw Size . The M6 screw size has a diameter of 9/64 inches. By the late 20th century, several countries have adopted the metric system. Metric & standard bolt screw sizes are determined by length and thread count. In fact, the bolt diameter is a little smaller and the nut diameter a little larger. But for flat head bolts, the length includes the height of the bolt head and for dome head bolts the length is measured from the highest point on the curved head. You can screw bolts on anything from drywall, metal, wood, to steel. 22 mm. Finding the correct size can be a daunting task if you dont know the imperial or metric system. Elevator boltSimilar to the carriage bolt but elevator bolt with a thin flat or countersunk head and a square undercut, used in conveyor system setups. They come in several types and sizes, which you can use in metal and wood. ANSI B1.13M, also identified as ASME B1.13M, defines the standard for metric screw threads in American units with metric units in parenthesis. Definitions of terms are located below the chart. For flat-headed ones that are countersunk, measure from the tip to the top of the head. Because this is approximately the same as the Major or Thread diameter the thread diameter measurement can be used for fully threaded bolts. If you use a bolt smaller than the hole it should go in, the bolt may fall out. fastenerdata makes no warranties or representations regarding . A wood screw has a pointed tip that aids in wood-to-wood fastening. Instead of using gauges in expressing diameter, the metric system uses millimeters. Metric Bolt Specification We refer to metric bolts using 'M' sizes followed by the diameter, thread pitch, and length. As a rule of thumb, the more lines a bolt has, the greater its strength. 4mm. From this number, you can gather a lot of information. These standards dictate things like thickness and screw thread. To do this, place the bolt head on a flat surface and place the ruler alongside it, aligning one end of the ruler with the center of the bolt head. Thread pitch and thread spacing mean the same thing, so dont get those two confused. US Hex Bolts. So, next time youre working on a project, you can acquire the bolt dimensions that you need easily. The M5s dimensions are significantly thicker than an M4 but can be used in several applications. All units in inches. Bolt size is measured across the head of hex and square bolts, from flat side to flat side, just like Standard bolts. These standards are very strict. Why? The gauge indicates the diameter. When measuring the length of a flathead screw, start on top of the head down to the stem. Some are a combination that works for either type. Flange bolts feature a nozzle, thereby speeding the assembly while eliminating the washer. Length is measured from under the head to the end of the bolt Note: Head sizes may dier from what is shown due to dierences between metric standards Length 16mm 12mm 8mm 7mm 6mm 5mm 4mm 3mm 10mm 14mm Coarse thread . SAE J429: The SAE J429 standard is a specification for bolts, screws, and studs that are used in automotive and related industries. That figure also refers to the bolts diameter. The metric system is based on millimeters, so metric socket sizes are generally sized like 8mm, 10mm, 12mm, and so on. The good news is that you can now confidently say that you know all about bolts and bolt size charts. You can use the same method to read a metric chart, but keep in mind that all measurements are in millimeters. Say, youve drilled a 33/64 inches hole, then 33 divided 64 is 0.515625 inches. The coating prevents corrosion from happening as a result of mortar and moisture. The defined diameter of metric bolts is actually slightly larger than the actual diameter. Just make sure youve got a high bolt grade or class. Make sure you get the right screw length, thread diameter, and screw threads for your project. The metric system was based on the meter, a system of measurement whose origin was in France in the 1970s. In general, smaller fasteners have finer threads, so the thread count is higher. M3 bolt = 5.5 mm M4 bolt = 7 mm M5 bolt = 8 mm M6 bolt = 10 mm (most common small engine bolt size) M7 bolt = 11 mm M8 bolt = 13 mm (very common bolt size) M9 bolt = 17 mm (very common bolt size) M10 bolt = 19 mm M12 bolt = 22 mm How to Read a Metric Screw Chart (ISO) ISO machine screw charts typically contain four things: Major diameter Minor diameter Pitch diameter Stress Area By now, you should know the major diameter and stress area of a machine screw. In standard bolt size charts, the thread pitch is the number of threads in one inch. A bolt gauge is divided into standard and metric sections. Use this tool to distinguish between coarse and fine thread bolts and machine screws, as well as the many thread pitches used on metric bolts and machine screws. The sixth column in both charts is the second most essential bolt dimension. Nuts and bolts are produced in standard sizes and dimensions. The next clue narrows things down for us. US Wood Screws - Nominal Sizes - Wood screws - nominal sizes vs. diameters. One part has coarse threads, while the other is an unthreaded shank. Bolts can me specified in metric using millimeters, but the standard, internationally-recognized descriptions of bolt sizes are in inches. Theyre commonly used in automotive applications and construction. Metric bolts are referenced using M sizes, such as the M8 bolt size. Now that you know how to take the measurement, the next step is to place the ruler down the axis to get the thread count. These dimensions are useful when attempting to tighten or loosen a bolt. Hex bolts can be used for infrastructure that requires a strong fastener with high tensile strength properties, they can also be used in tight spaces with limited access because tools can access them from all angles, or fastening wood, steel, or other materials in bridges, buildings, and more construction projects. Do you need to take your chances with any bolt that goes in the hole or give up the task altogether? Body Diameter - There may be a reasonable swell or fin under the head or die seam on the body not to exceed the basic bolt diameter by the following: 0.030" for sizes up to 1/2" 0.050" for sizes 5/8" and 3/4" 0.060" for sizes over 3/4" to 1-1/4" 0.090" for sizes over 1-1/4" to 2" 0.120" for sizes over 2" to 3" 0.190" for sizes over 3" Structural wood screws have an unthreaded shaft and coarse threads. In the standard size chart, the bolts are labeled as fractions, which happen to be the bolts diameters. " Drive. It specifies the dimensions and tolerances for both metric and imperial bolt head sizes, as well as the corresponding wrench sizes and other details. It comes in several sizes, which you can find in the packaging. Pitch combinations that seem to be in the middle can simply be described as fine pitch. The bolt head size is often only used to determine the wrench to use when tightening or loosening the bolt. In the metric system, its class is indicated via a class number that is imprinted on the bolt head. The M5 screw size has a diameter of 1/8 inch. You dont always measure from the top of the head. It most likely looks the same for all bolt types. What about using a metric bolt size chart? This kind of bolts was used in a carriage which was the basic transportation during inactive times. Phillips and slotted drives are the two main types. It doesnt matter if youre working outside or on furniture. Use a caliper: A caliper is a precision measuring instrument that can be used to measure the diameter of the bolt head. Theyre also common in laptops and the like. In both charts, theres a minimum and maximum diameter for each bolt. Inch. Metric Hex Bolt Dimensions | Atlanta Rod and Manufacturing | Manufacturing of Bolts, Concrete Embeds, Construction Fasteners, and Stainless Steel Bolts - Atlanta Rod and Manufacturing Common metric dimensions for hex bolts from Atlant Rod. It was introduced in the British Weights and Measures Act of 1824. If the bolt has threads, the threaded area is also included in this measurement. Thread Pitch The simplest and strongest form of anchor bolt is cast-in-place, another type is post-installed anchors. It happens, its frustrating, its time-consuming, I get it. Say youre building a treehouse, and you have a hole that fits the following description: It sounds a bit confusing, right? [in] Normal Fit [in] Close Fit [in] Loose Fit [in] #0: 0.0600: 0.076: 0.067: 0.094 #2: 0.0860: 0.102: 0.094: 0.116 #4: 0.1120: 0.128: 0.120: 0.144 . If you often do DIY, one of the popular items you are using is screws. Metric Bolt Sizes Metric nuts and bolts are commonly referenced using 'M' sizes, for example: M3, M8, M12. Do keep in mind that in reality, the actual diameter would vary between 1.9mm to 2mm because of manufacturing tolerances. These charts can give you a general idea of the tensile strength of standard and metric bolts as well as the material theyre most likely made from. U-boltA U-bolt is in the shape of the letter U with threads on both ends, its typical use is to support/clamp pipes through which fluids and gasses pass, and hold ropes together. The outermost part is where you will want to measure from. Raaj Sagar Steels manufacture and supply a comprehensive range of Slotted Machine Screws, Spanner (Snake Eye) Machine Screws. put up with me, the e-book will unconditionally song you new event to read. While almost all bolts have the same body diameter size measurements, there are other dimensions to consider depending on the shape of the bolt. They are significantly larger than most other screws. As for the metric chart, it more or less follows the same format until the third column. We use a lag screw to fasten components that handle a heavy load. Carriage bolt Carriage bolt also called coach bolt, with a round head and square neck, which makes the bolt distinguished from other bolts, also makes it self-locking when it is placed through a square hole and prevent the bolt from turning when tightened. The screw is usually inserted into an existing threaded hole or pass through the material to form its own internal thread, and then it is tightened by applying torque to head. Discover more about the small businesses partnering with Amazon and Amazons commitment to empowering them. These marks are radial lines; the more lines on the bolt, the greater its strength. 9/16. On the other hand, if you use a bigger-sized bolt that you need to use enough force to push it in, you can damage the hole. Choose from our selection of metric U-bolts, including over 850 products in a wide range of styles and sizes. The closer distance between these threads allows a tight hold. Elevator bolt size charts and carriage bolt charts also have two extra columns: Square Width and Square Depth. Use this chart to determine the mm size of the M value stamped on a bolt. Using a bolt with the right sizes is vital for jobs in various machinery and equipment. Head and Wrench Sizes - Hex Bolt, Lag Bolt, . Well, there is not always someone available to assist you. (Nominal diameter is more of a label than a size. If they are, you may have the wrong size of bolt. The standard system is otherwise known as the imperial system. It can be installed with only one tool, a spanner or wrench, working from one side. Metric Imperial; Millimetres (mm) In general, the first thing that you should do is consider whether youre using a bolt thats shorter or longer than 6 inches. The M4 screw size in inches is the equivalent of 0.15748. The bolt sizes are labeled differently in the metric size chart. Common Metric Socket Sizes 1/4" Drive 3/8" Drive 1/2" Drive 3/4" Drive 1" Drive 4mm 5.5mm 8mm 19mm 36mm 4.5mm 6mm 9mm 20mm 38mm 5mm 7mm 10mm 21mm 41mm 5.5mm 8mm 11mm 22mm 46mm 6mm 9mm 12mm 23mm 50mm 7mm 10mm 13mm 24mm 54mm 8mm 11mm 14mm 25mm 55mm 9mm 12mm 15mm 26mm 58mm 10mm 13mm 16mm 27mm 60mm A bolts name usually indicates its maximum diameter size, which is why a 0.4375-inch bolt is labeled 7/16 or an M24 has the number 24 in its name. In the USCS imperial system, a bolts tensile strength is usually indicated on its head using grade marks. If you do see what you are looking, we would love to assist you and give you a quote today! It allows you to drill directly into the surface without pre-drilling. Coarsely threaded bolts tend to have lower thread counts and are popularly used in general applications. US (inches) Metric (millimeters) 1/16: 1.6: 1/8: 3.2: 3/16: 4.8 The greater the pitch on metric fasteners, the more distance between threads. That said, its common to see abbreviated metric bolt formats, such as M14-50. Now let's break it down: 'M' shows that the bolt uses metric thread '5' is the bolt shank's nominal diameter in millimeters Every metric bolt is assigned a class number in terms of megapascals (MPa). Working out which of the variously sized and shaped bolts in front of you is the one you need can be quite daunting. Coarse Thread Sizes Fine Thread Sizes You can find it in security fixings, such as locks and hinges. In summary, diameter is listed first before the length. For example, in M6-1.0*20, the "M" means the Metric thread designation, the digit 8 refers to the Nominal diameter (in millimeters), 1.0 refers to the pitch, and 20 refers to the length. Composite deck ones have fine threads and a small head. So the systems are opposite in a way: The higher the TPI in a standard bolt, the finer the threads because there's more squeezed into a set space. Bear in mind that, while most bolts are made from carbon steel or alloy steel, bolts made from stainless steel exist. On the other hand, it still uses millimeters to measure length. Hanger bolts feature one side with a self-tapping lag screw thread to grip into the wood, with the other end having machine screw threads to accept a nut or thread into an internally tapped hole. The M5 screw size has a diameter of 1/8 inch. Anchor Bolts are heavy profile hexagon head bolts with full or partial thread configurations. The thread pitch is the distance between threads expressed in millimetres (measured along the length of the fastener). Class Grade Sizes (mm) Mini. Its the maximum stress a bolt can handle before it breaks. This is why we give the book . Several companies indicate the metric and imperial size on the packaging, which is helpful to most consumers. Quenched and tempered low carbon boron steel, Quenched and tempered medium carbon alloy steel with additives, Quenched and tempered medium carbon steel or carbon steel with additives, Quenched and tempered medium carbon steel, Quenched and tempered low or medium carbon steel, M shows that the bolt uses metric thread, 5 is the bolt shanks nominal diameter in millimeters, 1.0 refers to the thread pitch in millimeters, 20 is the overall length in millimeters, About 0.35 inches of space to keep the bolt flush to the material, Hot-dipped galvanized steel; suitable for outdoor use, Chrome or nickel-plated steel; can be used outdoors, Bronze or brass; expensive and more common in decorative and art pieces. That way, next time youre using bolts, you can take a quick look at the chart and find out exactly which one to use. The bolt dimension can also be expressed in imperial units. 1996-2023, Amazon.com, Inc. or its affiliates, YEEZET 652PCS Grade 8.8 M4 M5 M6 Heavy Duty Bolts and Nuts Assortment Kit Includes 13 Most Common Sizes, YEEZET 163 Set M4 M5 M6 Heavy Duty Bolts and Nuts Assortment Kit Alloy Steel Grade 8.8 Includes 13 Most Common Sizes, YEEZET 224PCS Grade 8.8 M6 M8 M10 Heavy Duty Bolts and Nuts Assortment Kit Includes 8 Most Common Sizes, Nut and Bolt Thread Checker (Inch & Metric) - 26 Male/Female Thread Identifier Gauges - 14 Inch & 12 Metric Sizes, SST Identibolt Bolt and Nut Identifier Gauge, Nut Bolt & Screw - Thread Gauge. Sex boltThe sex bolt, also known as a barrel bolt, connector bolt, or binding barrel, is a type of mating fastener combining a nut and a screw, it consists of a barrel with internal threads and a screw with external threads, both the barrel and screw have heads designed to clamp material between the head of the barrel and the head of the screw. All your fastener needs from a single source Aspen Fasteners 4807 Rockside Road, Suite 400, Independence, OH 44131 USA www.aspenfasteners.com | aspensales@aspenfasteners.com | 1-800-479-0056 Bolt Head A bolt's head is can be round, hexagonal, or square in shape. Flange Bolt Dimensions Chart and Stud Size in mm Flange Bolt Dimensions Chart and Stud Size in mm In this article, I have covered Flange Bolt Dimension Chart and Stud Size Dimensions for stud and bolt used in piping. It will not rotate in the assembly process, but is tightened by turning the nut. Bolt head size charts are used as a reference guide to help users select the appropriate size of bolt head for a given application. The M8 screw size has a diameter of 5/32 inches. If you do see what you are looking, we would love to assist you and give you a quote today! RAAJ SAGAR STEELS Address: 163, Dr.M. Pitch: the measurement between the apex of adjacent threads on the bolts shank, equal to the ratio of threads to unit length. More Recent 'Small Engine' Topics on LR Fix, M6 bolt = 10 mm (most common small engine bolt size). The bolt body consists of its shaft with the threaded area. Bolts are a type of essential fastener that often assembled with nuts. No inquiry is too large or too small, we specialize in locating hard to find items. We use the TPI to determine the threads fineness. A gauge number or fraction of an inch represents the diameter in the imperial system. Terms & Conditions-FAQ-About Us-Privacy policy - Facebook - Twitter, Metric & Standard Bolt & Screw Size Chart: M2, M4, M5, M6, M8, M10, gauge number or fraction of an inch represents the diameter, gauge number represents the fraction of an inch, 15 Warning symptoms of mold toxicity & sickness (What to do & 10+ signs not to ignore), 50-to-1 fuel mix chart gallons: Best 2-cycle oil mix, Best fish finders under $300, $500, & $1,000 for your boat. The thread pitch can be further classified as coarse, fine, and superfine. Its also referred to as the pitch. On the other hand, bolt torque size charts have many variables and different measurements for each bolt grade/class. US Hex Bolts - Metric - ANSI/ASME B18.2.3M Dimensions of Hex Bolts - Metric units. Shop products from small business brands sold in Amazons store. web the following table chart defines standard metric external thread size m1 6 to m18 per ansi asme b1 13m 1995 these thread sizes and A bolt head size chart is a tool that provides a visual representation of the different sizes of bolt heads, typically showing the size of the bolt head in both imperial and metric units. Depending on the application, they come in different forms and sizes. Unified Thread Standard (UTS): The Unified Thread Standard is a standard for screw threads that is used in the United States and Canada. Below is a table common fastener sizes and lengths and their US (Inch) decimal and closest fraction equivalent.