You see the words "drop forged" stamped on so many tools -- it makes
you wonder what the big deal is! Why do manufacturers want you to know
that a tool is drop forged?
If you have ever seen a blacksmith beating on a piece of red hot
iron with a hammer, you have seen the simplest type of forging.
Striking a piece of hot metal with a hammer is forging, and blacksmiths
have been doing this for centuries. As blacksmiths experimented with
new techniques, they learned that complex shapes could be created by
hammering metal into a die. The die contains the shape of the finished
product. Modern manufacturers use either a falling hammer or a powered
hammer to do the hammering (rather than doing it by hand), and usually
use dies on both sides of the piece. This is drop forging.
Manufacturers now use many different techniques to forge metal. Four of the most common include:
- Drop forging - Hammering hot metal into dies.
- Press forging - instead of forcing hot metal into a die with a hammer blow, it is pressed into the die with hydraulic pressure.
- Roll forging - The hot metal is pressed between two rollers.
- Cold forging - For smaller pieces, the metal can be pressed into the die without heating it significantly ahead of time.
The reason why manufacturers want you to know that a tool is drop
forged is because this tells you something about the strength and
durability of the tool. The other two ways to make a tool would be
casting it from molten metal or machining it (cutting material away)
from a larger block of metal. The advantage of forging is that it
improves the strength of the metal by aligning and stretching the grain
structure. A forged part will normally be stronger than a casting or a
machined piece.