All about Trapezoidal thread gauge


Trapezoidal thread gauge is one of the significant types of screw thread gauges which are accompanied by trapezoidal endings. It is one of the most commonly used thread inspecting methods which, when employed exhibits highest strength and allowances. Also known as Acme thread form these trapezoidal Threads are responsible for the translational motion seen in the machine-driven tools like lead screws. In lead screws, there is a requirement of rapid movement for the functioning of the screw jacks. In these screw jacks, the entire load of the exerted force is shared.


Trapezoidal thread gauge is mostly demanded when there is a requirement of high load at the head of lead screws. Used for creating threads at materials at 30° angle, these thread gauges are utilised to cut single point thread than a square point thread. Apart from that, there are several other advantages of trapezoidal gauge. Some of them are discussed below:


Benefits of trapezoidal thread gauge


From securing accurate estimation of pitch diameter to a precise measurement of threads of screw heads, a trapezoidal thread gauge is a unique device to ensure accuracy of the products. Other notable pros of trapezoidal thread gauge are:


  • Used in different types of machinery as lead screws for attaching elements like jacks, vices, lathes and jack stand.
  • Accurate verification of thread counts
  • Used for controlling the movement force of machine tools, jacks and testing machines.
  • Optimised efficiency and accuracy in the measurement readings after verification of threads.

Specification of Trapezoidal thread gauge: The basic proportions and volumes of a trapezoidal thread gauge are based on its basic dimensions like ISO 2903 – 1993, ISO 2904 – 1977 and Gauging Practice: DIN 103(9)-1985. According to the ISO specifications, the basic aspects are expressed as follows 7008-1988, IS 7008(4)-1999 and Gauging Practice: DIN 103(9)-1985.


Manufacturing Range of Trapezoidal thread gauge:


Trapezoidal thread gauges are produced in different forms such thread rings, check plugs as thread plugs. These plug gauges are of diameter from 8 mm to 355 mm and pitches from 1.5 mm to 12 mm.


Characteristics of trapezoidal thread gauges


For conducting measurements using trapezoidal thread gauges, the angle has to be 30° instead of 29°. All the measures have to expressed in a standard unit of millimetres.


According to the ISO standards the Trapezoidal threads are defined as where Tr is a variable that designates the value of a trapezoidal thread. An approximated value of diameter of a trapezoidal thread is supposed as 60, expressed in millimetres. On the other side, the amount of the pitch of diameter is taken as 9 with standard units of millimetres. With further progression of the equation, the width and the pitch is multiplied.


Although the proficiency of functioning of trapezoidal thread gauges is susceptible to change according to rate of friction of machine tools, this condition can lower the efficiency of the device and can reduce the accuracy of the production in industries. It is thus advisable to control the movement of the types of machinery to keep a check on the friction.