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Pins are devices used to hold objects or materials together. Pins usually have two components: a long body and sharp tips, which are made of steel (or occasionally copper or brass), while larger heads are usually made of plastic. The sharp body penetrates the material, while the larger head provides the driving surface. It is formed by pulling out thin lines, sharpening and adding heads. Nails are related, but usually larger. In machinery and engineering, pins are often used as pivots, hinges, shafts, clamps, and fixtures to locate or secure parts
The development of the needle is very similar to that of the perforated needle. Archaeological evidence shows that the curved sewing needle has been used for more than 4000 years. Originally, they were made of iron and bone by Sumerians to hold clothes together. Later, by passing the needle through the top corner of the staple, the pages were also fixed together with pins.
Later, many pushpins were made of brass, a relatively hard and malleable metal that could be used in the bronze age. After this development, higher strength steel was used, but it was prone to rust when exposed to humid air. The development of cheap electroplating technology makes nickel plating on steel possible. Nickel is not rusty, but it is easy to peel off the steel sheet in wet weather, which makes it rusty again. However, it took months or even years, and since normally only nickel plated steel pins were used temporarily to hold the fabric in place before plating, no further improvement was necessary. But please note that some modern special pins are made of rustproof and very strong titanium.
Walter hunt invented safety pins by making 8-inch brass pins into bent pins with springs and shields. He sold his invention rights to his friends to repay his debts, but he didn't know that he could make millions of dollars.
