Machining of accurate tapers with the aid of long-established gaging mehods is frequently time-consuming, requiring costly gaging equipment and mathematical skills. A typical setup may involve a surface plate, gage blocks, sine bar , height gage , and test indicator . More importantly , however , is the necessity of removing the tapered workpiece from the machine in order to measure the taper.
If , as often happens , the taper does not fall within the specified limits , it is necessary to replace the work in the machine and adjust it by the amount the taper is in error . Since the work can rarely be replaced in exactly its previous position on the centers , the adjustment of the machine may now be incorrect and it may be necessary to remove and replace the work a number of times before the desired taper is achieved.
The internal and the external taper micrometers , make it possible to measure taper directly and rapidly with relatively inexpensive equipment and without removing the work from the machine.