Threading is the process of creating a screw thread. More screw threads are produced each year than any other machine components.

The cutting tool moves across the workpiece linearly, taking chips off the workpiece with each pass. Number of passes depends on the number of threads per inch (tpi), workpiece material and its hardness.

Independent (selected) machining parameters for threading are: workpiece diameter, number of threads per inch, number of starts, and the cutting speed. Dependent (calculated) parameters are: pitch, spindle speed, linear speed of the cutting tool, thread lead angle, cutting time per pass, and total cutting time.

To be competitive, you have to create a screw thread at the maximum linear speed of the cutting tool (ipm). Since the linear speed of the cutting tool is directly proportional to the cutting speed (sfm), you have to know what the maximum cutting speed would be for a given workpiece material and its hardness. Information on the cutting speed data can be obtained from the cutting tool manufacturers.

Edmund Isakov, Ph.D., developed a threading calculator, which is functioning in Excel formulas. It includes major (computational) sheet and two sheets containing cutting speed data recommended by Sandvik Coromant.

It's not necessary to be "a rocket scientist" to use this calculator. Minimum system requirements: Windows 2000 or higher, Microsoft Excel 2000 or higher, CD-ROM Drive.