W.W. Greener's first intimation of the choke formation was derived from instructions given in a customer's letter, in early 1874. The customer's instructions described a choke, but did not give any details on the size or shape, or how it was to be obtained. Hence, W.W. Greener had to conduct many experiments to determine the perfect shape and size of a choke for a given bore. After that, he developed tools to produce the choke bore profile correctly and smoothly. The system of choke boring that he pioneered was so successful that it was later adopted by other manufacturers and hence, some authorities give him the credit for inventing the concept.