HORN: High Performance in Stainless Steels

Horn has developed a new, solid carbide milling cutter range especially for machining stainless steels. The tools are for milling stainless materials in the food, chemical and pharmaceutical industries as well as the precision engineering and watchmaking industries. In addition, due to their geometry and good chip breaking, the milling tools are suitable for machining numerous other materials. Due to the precise combination of the substrate, the macro and micro geometry as well as the IG3 coating, the milling system exhibits high performance and long tool life. The coating in particular offers high temperature resistance for machining steels alloyed with chromium, nickel and molybdenum.

Horn offers the solid carbide milling tools from stock in two types. The DSHPR variant is suitable as both a finishing and a roughing tool. The geometry is also adapted for trochoidal machining and plunging. The DSR type, with its very sharp cutting edge geometry and short design, is suitable for very small parts and unstable clamping conditions, such as in the medical and watchmaking industries. In the DSHPR line, all tools are available with four teeth and in diameters from 2 mm (0.079″) to 20 mm (0.787″). Horn offers the DSR variant with three teeth in diameters from 1 mm (0.039″) to 10 mm (0.394″).


HORN: Superfinishing of Bores with Supermini System

At EMO 2023 in Hannover, Horn is presenting an innovative extension for the Supermini system in the field of ultra-fine machining. The precision tool manufacturer has added a variant with a precision-ground rake face to the Supermini system especially for ultra-fine machining of bores. Due to precision grinding of the cutting edge, it is free from notches when magnified approximately 200 times. The tool system can be used from an inside diameter of 0.3 mm (0.012″). The sharp insert geometry enables process reliability even with very small infeed and cutting feed rates. The specially developed coating is suitable for stainless steels, non-ferrous metals and other metallic materials.

The insert of the Supermini Type 105 system requires only one tool holder for well over 1,000 insert variants. This applies equally to left-hand and right-hand versions. The carbide inserts are available in coated and uncoated versions in different grades for every application including hard machining up to 66 HRC. The patented droplet shape of the cross-section has a vibration-damping effect and delivers excellent repeatability when changing the insert. Internal coolant supply to the insert increases tool life, enhances cutting performance and improves chip removal. Horn offers the tools with elements for face clamping. This allows, for example, the insert to be changed easily without having to remove the holder from the machine.

History Horn Supermini:

In 1989, HORN launched the technically superior Supermini system at the world’s largest metalworking trade show, EMO in Hannover, Germany. After considerable technical development, it was possible to successfully manufacture precision internal grooving tools for bores down to 5 mm (0.197″) in diameter. The Supermini system was born and over time became one of Horn’s most successful products. In addition, the Supermini system was the first precision tool to benefit from Horn’s own in-house coatings.


HORN: Optimized for Swiss Type Lathes

Optimized for Swiss Type lathes

Paul Horn GmbH has never stopped developing and optimising its product portfolio. At the same time, it has integrated almost 100 percent of the added-value creation into its own production. The range of applications of the tool systems has grown considerably. Today’s machining operations across a diverse range of materials constantly demand further development and adaptation of the tool systems. Grooving with indexable inserts has become indispensable in modern production. Radial grooving, parting-off, axial grooving and internal grooving to micron precision are now part of everyday life in industry. For such machining processes, Horn relies on the S224 insert system, among others.

Horn has revised the clamping of the S224 type indexable insert for use in Swiss-type lathes. In order not to have to remove the holder for indexing or changing the insert, the Horn engineers relocated the clamping screw to the side. Clamping now takes place via a camshaft. This allows the insert to be clamped quickly at either side of the holder without having to remove it. Furthermore, this type of insert also eliminates the need to invest in special quick-change systems. For the user, in addition to simple operation with a torque wrench, there is the advantage of reduced machine downtime due to faster set-up. Horn offers the holder system from stock in left and right versions as a 16 mm x 16 mm square shank. All variants of the holder are equipped with an interface for internal coolant supply from above and below.


HORN Mastering Processes: Hard Machining


Mastering Processes: Hard Machining

Shorter machining times, high surface quality and the saving of grinding operations. These are just three of the advantages that hard machining with a geometrically defined cutting edge can bring to the user. With a high level of know-how in tool technology, Paul Horn GmbH offers numerous tool solutions to economically machine steels harder than 56 HRC. The cutting material CBN has proven itself suitable for grooving operations.

CBN (cubic boron nitride) is the second hardest known material on earth after diamond. Tools made of CBN wear much more slowly than other cutting materials when used appropriately. On  one hand, this makes it possible to achieve higher shape and dimensional accuracy, and on the other hand, hard materials (steel up to 70 HRC) can be machined reliably. There are no different grades of CBN. Differentiation is made by the CBN volume fraction, the fillers, the grain size and the ceramic/metallic binder phase (cobalt/nickel). This results in different CBN substrates. Numerous tool systems from Horn can be equipped with the cutting material CBN. In most cases, these are tools specially adapted to the respective application. However, Horn also offers standard tools equipped with this  very hard cutting material.

Hard machining with CBN cutting materials is usually done dry. This is possible because the cutting material has  high heat resistance and the high temperature within the chip formation zone has a positive effect. An insufficient supply of coolant or interruptions in cutting lead to high, thermally induced stresses in the structure of the insert. This can lead to cracks in the structure and thus possibly destroy the insert. During hard machining, the steel in the shear zone undergoes intense heating and is thus softened. Most of the heat generated in the shear zone is dissipated via the chip and not  transmitted into the workpiece. This means that there is no thermal influence on the insert edge  in the process. While carbide  suffers a massive loss of hardness at around 800 degrees Celsius, the hardness of CBN remains almost unchanged even at up to 1,200 degrees Celsius. Another important aspect is the chemical resistance, especially at the prevailing temperatures.

Numerous Advantages

Hard machining with a geometrically defined cutting edge in combination with CBN  has numerous advantages over grinding . High metal removal rates are possible with this process, which results in shorter machining times. Conventional machines  may be used. This offers the possibility of complete machining of the component. Even complex contours can be easily produced on a lathe. With grinding, on the other hand, the  wheels have to be elaborately profiled. The high surface quality that can be achieved with hard turning also saves on further grinding operations.

Lothar Horn (09.12.1956 – 05.02.2023)

Horn Group mourns the death of company director Lothar Horn

The entrepreneur Lothar Horn passed away on 5th February 2023 at the age of 66 after a long, serious illness. Lothar Horn was the managing director of Paul Horn GmbH in Tübingen. He shaped the Horn Group into an internationally successful manufacturer of precision tools with production sites in England, Italy, the Czech Republic and the USA. In addition, there are subsidiaries in France, Hungary, China, Mexico, Turkey and Thailand. At the same time, Lothar Horn made his company the largest commercial employer in Tübingen. In 1991, the IT-experienced and technologically-enthusiastic son of company founder Paul Horn joined his parents’ company. He became Managing Director on 1st January 1995. From 2009 to 2019, he was Chairman of the Precision Tools Association of the VDMA. In 2021, he received the Tool and Mould Making Medal of Honour, which recognises pioneers, visionaries and exemplary personalities in the industry. In 1999, Lothar Horn created new production and administration facilities as well as a demonstration, research and development centre at the main plant in Tübingen. Over the years, various expansions followed. Currently, the largest building in industrial use in Tübingen belongs to Paul Horn GmbH. With Lothar Horn’s son Markus, Managing Director of Paul Horn GmbH since 2018, the third generation is now leading the family business into the future, together with Matthias Rommel, also Managing Director.

Lothar Horn coined phrases such as “Technology determines costs” and “No car drives, no plane flies and no artificial joint can be inserted by doctors without using precision tools”. Loyalty to Tübingen was a major concern for him. Not only were investments in the company at this location important to him, but also social commitment. In addition to visible signs such as the Paul Horn Arena in Tübingen and the Paul Horn Hall at the Stuttgart Trade Fair Centre (Hall 10), he supported above all social institutions as well as the youth and junior staff of sports clubs, for example.

With Lothar Horn, the Horn Group loses an outstanding entrepreneur and a wonderful person.

The entire Horn Group mourns with the family.