The creation of pliers
The creation of a pair of water pump pliers
The KNIPEX Cobra® is the most popular pair of water pump pliers in the world. Let us show how it is made here.
This is how a pair of KNIPEX pliers is made
From the delivery of the raw steel to the packaging in the final production: the path of a pair of KNIPEX Cobra® high-tech water pump pliers is illustrated in several parts with pictures from our production.
We show you that next to the machines and the pliers, KNIPEX is primarily about people - they play an important role in the creation process of our products.
From raw material to calibration and blasting
1. Raw material
The raw material is supplied by trucks from the steel mill. The tool steel is stored on the stock rack. Up to 1,200 tons of the steel wires supplied as coils can be stored here. Our KNIPEX Cobra® is in one of the coils.
The KNIPEX pliers production uses around 600 tons of steel per month. What is special about it is that the guaranteed high-quality steel from German steelworks has been optimised according to KNIPEX specifications.
2. Cut to length
In the next step, the coil is cut to length. In the first step, the machine unrolls the steel wire and brings it into a straight shape. Now the press cuts the pliers steel lengthways - always 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 about to be forged. The advantage of the intially 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. Our water pump pliers reach our forging hammers as red-hot steel. The steel is shaped between two die halves by the impact force of the hammer bear. The tools that give the glowing steel its shape - the forging dies - are manufactured in-house by KNIPEX. The tremendous shock caused by the force of the hammers could cause the walls of the smithy to collapse. Therefore, the hammers stand on a steel spring-supported foundation. The KNIPEXians in the smithy work under heat and at high volume. Their dedication is another cornerstone of KNIPEX quality and makes the blacksmithing tradition of our region live on.
4. Cool down
The contours of the later pair of water pump pliers can be seen in the red-hot forged part. However, the steel pieces have to cool down before they can be further processed. Our water pump pliers with thousands of other forged blanks are waiting to come into the ridge 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, thereby sealing the gap in the closing die. This creates the high pressures that enable filigree forging (e.g. writings) in forgings.
Afterwards, this excess material must be removed. The plier halves are freed of excess steel in the ridge press shop. For this purpose, the employees place the forged blank in a ridge press. You set the tools, cutting plate and punch precisely. Certain tolerances must be observed. Deburring is a cutting process. The ridge presses separate the ridge from the pliers handle with tremendous force.
6. Calibration and blasting
Our water pump pliers expect the first surface treatment at blasting. The employees place the plier halves on a conveyor that leads into the blasting drum. There, an abrasive that is thrown onto the surface removes the scale that has been created by the previously introduced heat. After that, our water pump pliers feel smooth, almost like finished pliers. But there is still a long way to go. First, the Cobra® goes to calibration. In the calibration press, the plier halves are brought into the correct shape by the stamping process. Specially designed and manufactured tools from our toolmaking department are required for this.
From lasering to surface coating
The plier halves of our water pump pliers have been deburred and calibrated. The basic structure of the pliers is finished. Now it's in the details. First, the plier halves come to the laser system. The sharply focused beam of light cuts through the pliers. A laser is perfect for creating such fine teeth. This process is really important. Only with the teeth can our water pump pliers later be adjusted to different workpieces and grab them properly.
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 machining work. Various work steps are carried out simultaneously at different stations within the machine. This is very precise and quick. The employees 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. This is how KNIPEX creates efficient and time-saving work.
Now it's time to temper the plier halves. The plier halves go into large, heat-resistant baskets. You can see our plier halves being conveyed into an oven. When the baskets come out of the oven, they are conveyed into an oil basin – loaded with the plier halves. This process is called "quenching". Now the plier halves are hard, but too brittle. For the right viscosity, the plier halves are tempered: For a certain time, our Cobra® has to brave several hundred degrees Celsius. This gives it the optimal quality. The resulting hardness is checked during production on the Rockwell hardness tester.
10. Induction hardening
The teeth of a pair of KNIPEX pliers require special hardness, which is achieved with so-called induction hardening. The teeth on the tempered water pump pliers are heated using a high-frequency current. The teeth glow up again and are then quickly quenched. Then the plier halves are tempered again at a low temperature. Now the plier halves of our Cobra® have the right hardness.
11. Surface coating
If you look at the range of KNIPEX water pump pliers, you can see two different pliers surfaces. The chrome-plated versions of a water pump pliers are created in electroplating. The chrome pliers of this version have a valuable look thanks to the chrome plating. On the other hand, KNIPEX offers a zinc-phosphated surface variant of the Cobra®, which can be recognised by the familiar grey colour. Electroplating or zinc phosphating is the last process in which the pliers' halves are separated. KNIPEX can guarantee a long service life for both versions.
From assembly to shipping all over the world
After coating, the plier halves of the Cobra® are now ready for assembly. The outer and inner halves are assembled here. For the first time, you can recognise our water pump pliers as such. In the next step, the push button adjustment is attached. Employees insert the lock part, button and spring into the designated place. The machine does the rest.
The high KNIPEX quality is also unmistakable thanks to the mirror-polished jaw. "Pliesten" is the dialectal term from the region for the process which created the mirror polish, that can only be found on high-quality tools. The jaw of the Cobra® is processed on the grinding belt - afterwards the head of the pliers gleams. Every single pliers head is checked after polishing.
KNIPEX pliers are comfortable to hold. This is also due to the handles in various designs, which are also assembled on the pliers handles in the KNIPEX factory. The pliers of the first version come to the immersion system. Here, the handles are immersed in a liquid plastic paste. It sticks to the handles in such a way that a plastic handle is created after drying.
In the second version, the pliers have handles made of multi-component sleeves. In assembly, employees clamp the pliers and attach the sleeves to the handles with the right amount of glue. For electricians, the multi-component sleeve is also available in the VDE version, for which KNIPEX guarantees protection when working with up to 1,000 volts of electrical voltage. To be sure, we test every single pair of VDE-pliers at 10,000 volts.
15. Printing, oiling and packaging
The Cobra® with the non-slip plastic handles is now in the final production stage. 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. This entire process is called dabber printing.
Now, employees oil the pliers to protect them from rust. After that, the employees from the finishing line package Cobra®. Depending on the order, the pliers are packed in single boxes or boxes of six.
16. Ready to ship
With the order, our water pump pliers leave the KNIPEX plant. It leaves Cronenberg, their Bergisch home and maybe even the continent. Many KNIPEXians have held this pair of water pump pliers in their hands. They all accompanied our Cobra® on its path as an example of the more than 45,000 pliers manufactured per day. Without them there would be no pliers - and certainly no pliers in KNIPEX quality.