BS3643 defines the limits and tolerances for ISO screw thread gauges. The standard is divided into two parts. Part 1 is based on ISO 965/1 and ISO 965/3 providing the principles and basic data for specifications of ISO metric screw threads. For full table with more Property Classes - rotate the screen! Metric Bolts - Coarse Threads - Minimum Ultimate Tensile Loads Thread And BS3643 part 2 provides tabulated diameters and tolerances for coarse and fine pitch threads, based on ISO 965/2. Metric Bolt Sizes According to EN1993-1-8 § 3.8(1) for long joints where the distance between the centers of the end fasteners measured in the direction of load transfer is more than 15 d the design shear resistance F v,Rd of all the fasteners should be multiplied by the reduction factor β Lf specified in EN1993-1-8 equation 3.5.

The number 1.0 is the thread pitch of the bolt, which is the distance between threads, in millimeters. where e 2 is the distance between the center of the edge bolt and the end of the plate measured perpendicular to the load transfer direction, p 2 is the distance between the centers of neighboring bolts measured perpendicular to the load transfer direction, and d 0 is the diameter of the bolt hole. The interaction between shear and tension is expressed in EN1993-1-8 Table 3.4 according to the following linear relation: According to EN1993-1-8 Table 3.4 the shear strength of the bolt may be based on the tensile stress area.The calculated strength properties for coarse pitch thread bolts may be used conservatively for fine pitch thread bolts. According to EN1993-1-8 § 3.6.1(4) the design shear resistance F v,Rd should only be used where the bolts are used in holes with nominal clearances not exceeding those for normal holes as specified in EN 1090-2 'Requirements for the execution of steel structures'.

The bearing resistance of the bolt F b,Rd should be verified against the applied shear load F v,Ed in accordance with EN1993-1-8 Table 3.4:

Punching strength of bolts

The resulting hole diameter d 0 for each type of hole (normal, oversize, short slotted, long slotted) is determined by adding the nominal clearance given in EN 1090-2 Table 11 to the nominal diameter d of the bolt. A is the appropriate area for shear resistance. When the shear plane passes through the threaded part of the bolt A is equal to the tensile stress area of the bolt A s. When the shear plane passes through the unthreaded part of the bolt A is equal to the gross cross-sectional area of the bolt A g. For typical coarse pitch thread bolts the standard sizes are: M3, M3.5, M4, M5, M6, M7, M8, M10, M12, M14, M16, M18, M20, M22, M24, M27, M30, M33, M36, M39.

For full table with more Property Classes - rotate the screen! Metric Bolts - Coarse Threads - Proof Loads Thread The design shear resistance of bolts F v,Rd as given in EN1993-1-8 Table 3.4 is only valid when the bolt is used in holes with nominal clearance not exceeding the values given in the standard EN 1090-2 'Requirements for the execution of steel structures', as specified in EN1993-1-8 §3.6.1(4). where e 1 is the distance between the center of the end bolt and the end of the plate measured parallel to the load direction, p 1 is the distance between the centers of neighboring bolts measured parallel to the load direction, and d 0 is the diameter of the bolt hole. The nominal gross area A g corresponds to the cross-sectional area of the unthreaded part of the bolt:The design resistance of a group of fasteners may be taken as the sum of the design bearing resistances F b,Rd of the individual fasteners provided that the shear resistance F v,Rd of each individual fastener is greater than or equal to the design bearing resistance F b,Rd. Otherwise the design resistance of a group of fasteners should be taken as the number of fasteners multiplied by the smallest design resistance of any of the individual fasteners as specified in EN1993-1-8 § 3.7(1). For this case elastic linear distribution of internal forces should be used as specified in EN1993-1-8 §3.12. As noted, the specification of metric bolts includes the definition of thread pitch, but if this is omitted then a coarse pitch is assumed. Metric fasteners are available with either coarse or fine thread pitches with some metric bolt sizes offering extra fine thread pitch options. It is worth noting that metric bolts with a coarse thread pitch have more threads per inch (they are more closely spaced) than comparable imperial bolts. List of common metric bolt sizes. Metric Coarse A set screw fastens materials together by twisting it directly through the last component, into a pre-threaded hole, pulling everything together. A shoulder bolt fastens materials by passing them through pre drilled holes in the adjoining materials and cramping them between the head at one end and a nut on the other. Additional washers are often used to spread the load further. A set screw is fully threaded from underneath the head and a bolt is partially threaded (has a part-plain shank). A bolt is used when you know the length you need and a set screw can be used as a bolt if you need more flexibility in the length. The second number corresponds to the ratio of yield strength to ultimate strength e.g. 60% for class 4.6 leading to a yield strength of 0.60 × 400 MPa = 240 MPa.