d1and d2can be obtained from ->ACME General Purpose Thread Designer Calculator Shear Area of General Purpose Acme Threads: For computing the shear area per inch length of engagement of the external thread, the maximum minor diameter of the internal thread D1, and the minimum pitch diameter of...
External general purpose ACME Thread size table chart There are three classes of General Purpose ACME threads, 2G, 3G, and 4G each class provides some clearance on all standard size diameters for free movement, and are used in assemblies with the interna