What is the use of Three wire method ?
The accurate measurement of thread pitch diameter, which may be perfect as to form and lead, presents certain difficulties which result in some uncertainty as to its true value. The adoption of a standard uniform practice in making such measurements is, therefore, desirable in order to reduce such uncertainty of measurement to a minimum. The “three-wire method” of measuring thread pitch diameter, has been found to be the most generally satisfactory method when properly carried out, and is recommended for universal use in the direct measurement of thread plug and thread setting plug gauges.
How to Calculate Pitch diameter unsymmetrical threads?
Pitch diameter unsymmetrical threads calculator uses Thickness of Screw = Micrometer Reading+(Screw Pitch/(tan(Large Angle)+tan(Small Angle)))-Wire Diameter*(1+cosec((Large Angle+Small Angle)/2)*cos((Large Angle-Small Angle)/2)) to calculate the Thickness of Screw, The Pitch Diameter Unsymmetrical Threads formula refers to the diameter of an imaginary cylinder that would pass through the thread profile at the point where the width of the threads and the width of the spaces between the threads are equal. Thickness of Screw is denoted by Du symbol.
How to calculate Pitch diameter unsymmetrical threads using this online calculator? To use this online calculator for Pitch diameter unsymmetrical threads, enter Micrometer Reading (M), Screw Pitch (P), Large Angle (a1), Small Angle (a2) & Wire Diameter (G) and hit the calculate button. Here is how the Pitch diameter unsymmetrical threads calculation can be explained with given input values -> 56105.38 = 0.0082+(0.003/(tan(0.00872664625997001)+tan(0.003490658503988)))-0.0012*(1+cosec((0.00872664625997001+0.003490658503988)/2)*cos((0.00872664625997001-0.003490658503988)/2)).