SIR - Regarding the story about Parkinson's vises (T&A, January 3), I too have a Parkinson model vise for which the steel parts were made and the brass parts finished by the late Frank Woodall, of Shipley.

He worked at Parkinsons and was a prolific maker of remarkable working models of engines, mining machinery and boats.

After he retired I asked him if he knew of anyone who had one of these vises which they might be prepared to part with. Better than this, he presented me with mine, together with the following account: "Joseph Parkinson sold small treadle lathes and supplied vises to go with them. He had the vises made in Sheffield.

"Calling to see the firm in Sheffield, he saw a cart-load of Parkinson vises going away. Instead of taking legal action he said he would make better vises.

"His son came home from night school and said he had learned about buttress threads. This was the start of the Parkinson vise with buttress screws and half-nuts. Manufacturing is believed to have started in 1893.

"The little brass vises were made for advertising in 1925. In 1965 a box was found with dozens of brass bodies but no screws. Many pillaged the box and wanted a screw making. Senior management heard about it and joined in the idea with enthusiasm (so long as it was kept quiet)."

Brian R Burrows, West Way, Shipley