A needle is a thin, cylindrical instrument, pointed at one end, that is used in sewing, knitting, and other methods of joining material with thread. Needles used in sewing machines have a tiny hole, called the eye, near the point to carry thread into the fabric being sewn. Needles used for hand sewing have the eye at the end opposite the point. Instead of an eye, crocheting needles have a hook at one end to carry the thread. Most needles are made of lengths of steel wire that are heated and then straightened by rolling. The points are ground on a grindstone, and the eyes are made by a punching machine. Each needle is then tempered, or strengthened, by the heat of a gas flame. Finally, it is given a smooth polish. Needles used for high-speed sewing machines are plated with nickel or chromium to give them greater resistance to heat and to reduce friction.
There are hundreds of varieties of sewing needles manufactured. Some needles are curved for special uses. Varieties of curved needles are used for upholstering and shoemaking. In medicine curved surgical needles are used for sewing tissue and hollow needles are used in hypodermic syringes.