Pinchbeck (alloy) Pinchbeck (alloy) Pinchbeck is a form of brass, an alloy of copper and zinc, mixed in proportions so that it closely resembles gold in appearance. It was invented in the 18th century by Christopher Pinchbeck, a London clockmaker. Since gold was only sold in 18-carat quality at that time, the development of pinchbeck allowed ordinary people to buy gold 'effect' jewellery on a budget. The inventor allegedly made pinchbeck jewellery clearly labelled as such. Pinchbeck jewellery was used in places like stagecoaches where there was a risk of theft. Later dishonest jewellers passed pinchbeck off as gold; over the years
British Standard Brass of the tube or cut right through it. Brass tube threads can be confused with the British Standard Cycle thread, one of which that is most common is also 26 tpi. The difference being the thread angle of the British Standard Cycle is the same as the metric thread angle of 60 degrees. Nominal sizes are usually in the range to 2 inches. British Standard Brass British Standard Brass or British Brass Thread is an imperial unit based screw thread. It adopts the Whitworth thread form with a pitch of 26 threads per inch and a thread angle of 55