It is applied to a cutting motion that is perpendicular to the diameter being cut. Radial infeed is one of the more common threading methods, if the conditions are suitable. Four methods can be applied for compound infeed threading:

For example, a square thread will require a radial infeed, while an Acme thread will benefit from compound infeed. With the exception of some very fine leads and soft material, the majority of threading cuts will benefit from a compound infeed or modified compound infeed (angular method), providing the thread geometry allows this method. Specified infeed is typically selected to achieve the best cutting conditions for the insert edge in a given material. 29:ġ) Plunge method - also known as the radial infeedĢ) Angular method - also known as the compound or flank infeedģ) Modified angular method - also known as the modified compound (flank) infeed Three basic thread infeed methods are shown in Fig. Infeed is the type of motion from one pass to the next. The way a threading tool enters into the material can be programmed in several ways, using two infeed methods available. Spindle speed is always programmed in direct r/min mode (G97) not in the constant surface speed mode G96. Thread Lead = the distance the threading tool will advance along an axis in one revolution of the spindle In metric drawings, the pitch is specified as part of the thread designation. Thread Pitch = the distance between two corresponding points of adjacent threads. Internal V-threads (60-degrees for metric or U.S. It can be calculated from these common formulas ( TPI is the number of threads per inch):Įxternal V-threads (60-degrees for metric or U.S. Regardless of the threading method used, the depth of a thread will be required for various calculations. As single point threading is a multi-pass operation, the CNC system provides spindle synchronization for each threading pass. For single start threads, the lead and the pitch are identical. Feed rate for threading is always the lead of the thread, never the pitch. The uniformity of the thread is controlled by the programmed feed rate in feed rate per revolution. By definition, a single point threading is a machining process of cutting a helical groove of a specific shape with a uniform advancement per spindle revolution. As a threading operation is both a cutting and a forming operation, the shape and size of the threading insert must correspond to the shape and size of the finished thread. The method of thread cutting on CNC lathes is called single point threading using an indexable threading insert.

Mazak thread programming