how-are-bolt-cutters-manufactured

How are bolt cutters manufactured?

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Worker supervising drop forging machine where block of white hot metal is about to be pressed into a casting die (or mould) by a drop hammer. Bolt cutters are heavy duty tools which are factory-made with precision machinery and high-quality steel. They are made by a process called “drop forging”, where the metal is heated up and then pressed into a mould, called a die, by a falling or powered hammer dropped from above (hence the name “drop” forging). This method is used because it aligns and stretches the grain of the metal in a special way which results in a stronger tool with a longer lifespan than those cast from molten metal or machined (cut from a block).

Blades

Strong arm symbolising strength which steel bolt cutter blades need to have After forging, bolt cutter blades are subjected to two further processes, hardening and tempering, which give them the extreme level of strength that they need.
First stage of steel hardening process involving heating to high temperature of steel blade

Hardening

In the first stage (hardening), each blade is heated with a gas torch (or by machine) until it glows red. This occurs above 480 degrees Celsius (900 degrees Fahrenheit).

Second stage of steel hardening process where blade is rapidly cooled in water It is then cooled rapidly in clean water, which results in it becoming very hard, but more brittle.
Second stage of steel hardening process involving heating to modest temperature of steel blade

Tempering

The second stage (“tempering”) reduces the brittleness of the blade and leaves it more supple and resilient.

This time the blade is heated only to a limited point and then the heat is removed and the tool is allowed to cool more slowly. At the end of this process the blade should be tough and hard-wearing and unlikely to snap.

Handles

Diagram of elements used in drop forging process including hammer (ram), upper mould (die), lower mould (die), anvil and metal workpiece.

Drop forged

Where the handles of bolt cutters are solid they will have been produced by the same method as the jaws, i.e. drop forging. This makes for a very strong, solid tool which will last a long time, if looked after.

Spray paint being used to coat a large cylinder After being forged, the handles are given a paint finish in a process called powder-coating.
Stainless steel tubes of different diameters laid side by side.

Cold roll formed

Longer handled versions of bolt cutters are now often made of tubular steel. This is steel which is “cold roll formed” (rolled by huge machines at room temperature) into tubing. This kind of metal is strong, and lighter than drop forged steel, making it ideal for long-handled cutters, where the handles are under greater pressure when in use.

Handle grips

Orange handled bolt cutters with vinyl or rubber handle grips Most long bolt cutters have tough, hard-wearing grips at the end of the handles. These will have been moulded out of rubber or vinyl and fitted by machine over the metal handle.
Wonkee Donkee says: "Look out for bolt cutters with multi-component grips; they're really comfy."