Sheet metal processing with a hammer

Sheet Metal Processing - Manual vs Machine

Sheet metal processing, which forms thin metal into desired shapes, can be broadly classified into machine sheet metal processing and manual sheet metal processing. Manual sheet metal forming, which is often used for automobile body repairs, is a process in which metal is formed by hand using tools such as hammers and fixtures. What are the types of tools and methods used in manual sheet metal working?

Hammers and Plates Used in Sheet Metal Working

Hand sheet metal working is a processing method mainly used to repair sheet metal for automobiles, crafts, stove chimneys, rain gutters, and so on. Hammers are widely used in hand sheet metal working, and these hammers can be broadly classified into wooden hammers and steel hammers.

Wooden hammers do not deform metal as much with each strike. Therefore, less work hardening of the material is possible. They are often used for rough forming in the initial stages or for shallow, large-area forming. Steel hammers, on the other hand, deform the metal in a single strike, resulting in a large amount of work hardening. Therefore, they are generally used for localized, high deformation forming.

Regardless of whether wooden or steel hammers are used, the tip of the hammer used should be machined to match the desired shape to be formed. When forming a small circle, a hammer with a pointed spherical tip is used, and when forming sheet metal into an elongated shape, a hammer with an elongated oval tip is used. The use of a hammer with a tip that matches the shape to be formed makes the process easier.

In manual sheet metal processing, a hammer is used to (1) deform the metal into the desired shape and (2) avoid breaking the material when force is applied. There are various types of hammers and they are used for different purposes and at different stages of processing. These hammers are used in a fixed position using a special wooden mortar, vise, or other fixture, whereas the hammers called 'dollies' used in automotive sheet metal repair are hand-held and not fixed.

Relationship between the striking points of the hammer and the striking point of hammer

It is important to understand that in manual sheet metal working using a hammer and hammer pad, the way the material is deformed is determined by the relationship between the pad and the material on the ground and the position where the pad and hammer strike.

When the hammer strikes the flat surface of the material and the plate, the material is flattened without changing its angle, and the entire material is stretched. This process is called rooster punching, which is often used in finishing. When the hammer is struck close to the point of contact between the hammer and the workpiece, the workpiece is lifted up, while when the hammer is struck far from the point of contact between the hammer and the workpiece, the workpiece is lowered down. Manual sheet metal processing using hammers and hammers requires a good understanding of the relationship between these hammering points and hammers, and the skill to work appropriately according to the purpose and shape of the deformation.

How to Use a Hammer in Automobile Sheet Metal

In sheet metal processing used in automobile body repair work, the key to the work is the action of striking the metal with a hammer. It is important that the striking surface of the hammer strikes the material surface at a right angle and that the hammer strikes with the entire surface to transmit force evenly to the material without bias. The following is an explanation of how to use the hammer to apply force to the material correctly.

First, hold the hammer so that the entire striking surface of the hammer is in contact with the material surface. If you try to grip the handle tightly with all fingers, the angle of contact between the striking surface and the material will be blurred. Hold the end of the hammer handle with your pinky and palm only, and support the other fingers by resting them on the handle. Once the hammer is properly held, strike with the wrist as a fulcrum, snapping the hammer up and down. Note that if the striking surface of the hammer strikes at an angle to the material surface, a crescent-shaped indentation will occur, which will greatly damage the strength and appearance of the product.


In manual sheet metal working, it is of utmost importance to be skilled in the use of the hammer and the hammerhead in order to efficiently finish the desired shape. It is important to understand well how to grip the hammer and how to properly strike the hammer and material surface, and to train steadily until you are able to strike the ideal blow unconsciously.