The making of pliers
How are KNIPEX pliers made?
The KNIPEX Cobra® is our most popular pair of pliers. Let us show you show it's made.
From the delivery of raw steel to packaging the final product, the creation of a pair of KNIPEX Cobra® water pump pliers is illustrated in the several pictures below.
In addition to machines, technology, and high quality materials it is primarily about the people involved in the creation process of our products.
From raw material to forging and calibration
1. Raw material
Raw material is delivered by trucks from the steel mill stored in one of our warehouses where up to 1,200 tons of steel wire coils can be stored. The materials that make our KNIPEX Cobra® is in one of those coils. To produce KNIPEX pliers roughly 600 tons of high-quality German steel is used per month.
2. Cut to length
First, the machine unrolls the steel wire and brings it into a straight shape. Next, the press cuts the pliers lengthwise, consistently to the same length. The cut pieces of steel are called "Piller" according to the Cronenberger dialect. After the cut, our soon-to-be Cobra® is ready to be forged. The advantage of the initial round shape is a shorter heating time. As a result, the material is less stressed and the forging quality is higher.
At the start of the forging process, each individual "piller" is heated to over 1,000° C. The red-hot steel is shaped between two die halves by the impact force of the forging hammer. The tools that give the glowing steel its shape - the forging dies - are manufactured in-house by KNIPEX. The KNIPEXians in the forge area work under heat and their commitment to this process keeps the blacksmithing tradition of the region alive.
4. Cool down
Before they can be further processed, the recently forged red-hot steel pieces of the pliers need to cool down. They wait with thousands of other forged blanks to enter into the burr press shop.
Die forging works in such a way that more red-hot steel is introduced into the hollow mold in the die than necessary. When the hammer strikes, the excess material is pushed out through the joint between the two die halves, sealing the gap in the closing die. This creates the high pressures that enable filigree forging (e.g. writings) in forgings. Afterwards, the excess material must be removed in the press shop. To do this, the forging blank is placed in a burr press. The tools, cutting plate and punch are set in place and the deburring (or cutting) process begins.
6. Blasting and calibration
Pliers halves are placed on a conveyor that leads into the blasting drum which is the first surface treatment the pliers will get. In the blasting drum, an abrasive is thrown on the surface to remove the scales that have been created by the previously applied heat. After that, the surface feels smooth, almost like a finished pair of pliers but there is still a long way to go. Next the pliers must go to calibration. In the calibration press, the plier halves are brought into the correct shape by the stamping process.
From lasering to surface coating
Now that the plier halves have been deburred and calibrated, the basic structure of the pliers is ready and moves into lasering. A laser is the perfect tool for creating such small, sharp adjustments to the tool. With these laser adjustments our water pump pliers can be modified to suit different workpieces allowing end users to find the correct adjustment position.
8. Mechanical processing
The next stage for the plier halves is the rotary indexing machine (RIM). This system, designed in-house by KNIPEX, does all the mechanical work precisely and quickly. The employees running the machine only have to insert a box with the plier halves into the RIM. A camera registers the position of the halves so that they are guided into the RIM by a robot arm. The machine completes the rest entirely on its own.
Now it's time to temper the plier halves. The plier halves go into large, heat-resistant baskets that are placed into an oven. When the baskets come out of the oven, they are conveyed into an oil basin. This process is called "quenching". Now the plier halves are hard, but brittle. In order to achieve the correct viscosity, the plier halves need to be tempered. Our Cobra® pliers brave several hundred degrees Celsius for a specific amount of time. The resulting hardness is checked on the Rockwell hardness tester.
10. Induction hardening
The teeth of a pair of KNIPEX pliers require special hardness, which is achieved by induction hardening. To do so, the teeth on the pair of tempered water pump pliers are reheated using a high-frequency current. The teeth will glow once again, are quickly quenched and then tempered at a lower temperature. The plier halves and teeth now have the right hardness.
11. Surface coating
If you look at the range of KNIPEX water pump pliers, you will notice two different pliers surfaces, both of which offer a long service life. Our chrome plated water pump pliers are created in the electroplating department. The other type of surface KNIPEX produces is zinc-phosphate, which looks a grayish black. Electroplating or zinc-phosphating is the last process in which the pliers' halves are separate.
From assembly to shipping all over the world
After coating, the Cobra® are now ready for assembly. The outer and inner halves are assembled and for the first time, you can recognize our classic water pump pliers. In the next step, the push button adjustment is attached; employees insert the lock, button and spring into the designated place and the machine does the rest.
The jaw of the Cobra® is processed on a grinding belt until it gleams. Every single pliers head is checked after polishing to ensure satisfaction. This mirror-polished look, or "Pliesten", is one mark of the many ways KNIPEX is a high-quality tool manufacturer.
KNIPEX offers various handle designs, all of which are comfortable to hold. The most popular handle type are plastic coated which are handles immersed in a liquid plastic compound. The second type are multi-component grips and finally, for electrician's, the multi-component grips in VDE or ASTM insulated versions. These provide protection when working with up to 1,000 volts of electrical voltage but every single pair is tested at 10,000 volts to ensure the highest level of safety.
15. Printing, oiling and packaging
Now that the correct handles are on our pliers, the Cobra® can be moved into pad printing. First, the article number and other lettering such as "KNIPEX" or "Made in Germany" are printed on the handles. Then the pliers run through an oven on a conveyor. Next, the pliers are oiled to protect them from rust. After that, the pliers are packaged by the finishing department and prepared for shipment to the USA. Once in the USA the tools will be packed into their final retail friendly clamshells, individual boxes or sets.
16. Ready to ship
By the time our new pair of pliers have left the KNIPEX plant in Germany they will have been held by many KNIPEXians to ensure the highest level of quality. Without our dedicated team there would not be any KNIPEX pliers manufactured - more than 45,000 per day - and there certainly would be no KNIPEX quality.