Cold chisels

These are often used by the body repair worker for cutting out components which have been damaged, chipping off rusted bolts which cannot be removed by normal methods,and chiselling sections which cannot be cut be snips or hacksaws. Chisels are made from high-quality steel. The cutting edge is specially hardened and tempered,while the remain- derof the chisel is left soft to enable it to withstand hammer blows.
The chisel is subdivided into cutting edge,shank and head. The cutting end has a wide,flat taper and is ground on both sides to form the cutting edge. Metal working chisels should have sufficient length to allow the shank to be gripped properly,as short chisels are difficult to handle and may lead to accidents through hammer blows if the head pro- jects insufficiently beyond the gripping hand. On the other hand excessively long chisels cannot be guided so well and consequently may vibrate and break easily. Only the cutting edge of the chisel is hardened. When the chisel has been in use for some time a ridge forms on its head which is called a burr; this needs to be removed because it may lead to accidents during use. Chisel joint angles vary between about 30°and 60°,the sharper angles being used for cutting softer metals. The metal worker’s chisel is flat,and is used for working on flat or curved surfaces of thin sheet. It is also used for cutting solid bolts and rivets.Car Repair Talk's forum.