The unique Robert Sorby thread cutting system allows the woodturner to cut a series of different sizes of thread on turned projects. This may enhance such projects as boxes, needle cases, lamp standards and musical instruments, where the ability to assemble and disassemble is an advantage. These thread cutters are available in pairs internal and external cutters -in 10, 16 and 20 threads per inch. The coarser thread is ideal for larger projects. These cutters have been designed by Robert Sorby specifically for cutting in wood rather than metal as is traditionally the case with engineers thread chasers. This design makes for a clean and accurate thread time after time. The system also includes a special calliper (ref 973) which makes dimensioning threaded or push fitments that much easier. The anvil is calibrated to either a 10, 16 or 20 tpi setting. The fourth, unmarked anvil enables sizing for a push fit. There is also a relief cutting tool (895H) which is ideal for producing the necessary recess at the end of internal threads and a tool support (ref 893H), The latter also known as an arm rest is used in a style of thread cutting advocated by some practiced turners.