Search results
Results from the WOW.Com Content Network
The major diameter is given by 6p 1.2, [4]: 12 rounded to two significant figures in mm and the hex head size (across the flats) is 1.75 times the major diameter. BA sizes are specified by the following British Standards: BS 57:1951 — B.A. screws, bolts and nuts
Even though #14 and #16 screws are still available, they are not as common as sizes #0 through #12. [citation needed] Sometimes "special" diameter and pitch combinations (UNS) are used, for example a 0.619 in (15.7 mm) major diameter with 20 threads per inch. UNS threads are rarely used for bolts, but rather on nuts, tapped holes, and threaded ODs.
Other (usually smaller) sizes may occur to reduce weight or cost, including the small series flange bolts defined in ISO 4162 which typically have hexagonal head sizes corresponding to the smaller 1st choice thread size (eg. M6 small series flange bolts have 8mm hexagonal heads, as would normally be found on M5 bolts). [10]
ISO Metric Trapezoidal Screw Threads; Limiting Sizes for Nut Threads from 8 to 100 mm Nominal Diameter: Active: DIN 103-6: ISO Metric Trapezoidal Screw Threads; Limiting Sizes for Nut Threads from 105 to 300 mm Nominal Diameter: Active: DIN 103-7: ISO Metric Trapezoidal Screw Threads; Limiting Sizes for Bolt Threads from 8 to 100 mm Nominal ...
The minimum limits for external (or bolt, in ISO terminology), and the maximum limits for internal (nut), thread sizes are there to ensure that threads do not strip at the tensile strength limits for the parent material. The minimum limits for internal, and maximum limits for external, threads are there to ensure that the threads fit together.
A screw thread, often shortened to thread, is a helical structure used to convert between rotational and linear movement or force. A screw thread is an inclined plane wrapped around a cylinder or cone in the form of a helix, with the former being called a straight thread and the latter called a tapered thread.
To simplify matters, the term hexagon is used in this section to denote either bolt head or nut. Two spanners, both nominal size 5 ⁄ 8 in, with a diagram superimposed to show the logic that allows them both to be nominal size 5 ⁄ 8 in when their actual sizes are clearly different (across-flats distance vs screw diameter). The across-flats ...
Thus they are instead given as basic dimensions. In modern practice basic dimensions have a rectangular box around them, or sometimes the word "BASIC". BC or B.C. bolt circle: BCD or B.C.D. bolt circle diameter: BHC bolt hole circle Same definition as the bolt circle diameter BHCS: button head cap screw: Like an SHCS but with a button head. BHN