Horn Supermini: The New Benchmark in Chip Control

by Bernard Martin

Horn USA continues to push the boundaries of fine-bore machining with the latest iteration of its Supermini system—now featuring a sintered chip breaking geometry that sets a new standard for process reliability and productivity in internal turning applications.

For decades the Supermini has been one of Horn’s most versatile and successful tooling systems. The introduction of sintered chip breaking geometry is a pretty significant advancement in small boring, addressing one of the most persistent challenges in internal machining: uncontrolled chip formation.

What Makes the New Supermini Different
At the heart of this innovation is the sintered geometry built directly into the insert. Unlike traditional chip breakers that are ground or laser-cut as a secondary operation, Horn’s geometry is fully sintered into the cutting edge during manufacture.

This approach delivers several advantages:

• Reliable chip control across a wide range of materials. The geometry actively guides and shapes swarf, encouraging predictable chip breakage even during light feeds and small infeed settings.
• Reduced downtime and smoother cutting. Long, stringy chips that wrap around the tool or clog the hole are dramatically reduced, increasing uptime and reducing secondary chip-removal tasks.
• High process stability. The geometry extends well into the corner radius of the insert, providing consistent chip control across internal, face, copy and reverse turning operations.

Built for Precision and Practicality

Boring, profile turning, internal grooving, threading, chamfering, face grooving, drilling and slot broaching: The Supermini tool system can be adapted for numerous machining operations.

The solid carbide inserts are used for boring from a diameter of 0.2 mm to around 10 mm. Horn developed the carbide blanks for the tool as a teardrop shape. This enables large, precise contact surfaces in the tool holder, which results in greater rigidity of the overall system.

The teardrop shape prevents the insert from twisting, which leads to consistently precise positioning of the center height of the tool. With long tool overhangs, it reduces deflection and minimizes vibration during turning.

Depending on the application and the diameter to be machined, Horn offers the inserts in three different sizes (types 105, 109 and 110) and different blank types. 

The "Supermini" tool system - now with chip breaker geometry - can be adapted and used for numerous machining operations.

All types allow internal coolant supply directly to the cutting zone. The Horn tool portfolio contains around 2,500 different standard variants of the Supermini. In addition, Horn solves users' machining problems with countless customized solutions.

Chipbreakers make all the difference
One of the biggest challenges in internal machining is the generation of long chips. Depending on the material, boring often leads to stringers that wrap around the tool, clog holes or, in the worst case, lead to tool breakage. This is where chip breaking geometry can help. It guides and shapes the chip and causes it to break.

On the left: Without Chipbreaking technology can lead to a rats nest of chips. On the Right: chip breaking geometry RS105.1833.2.6.U20

According to Horn USA : "Previously, specially lasered or ground chip breaking geometries were used for this purpose. However, this increased the cost of the inserts. With the new Supermini type 105, Horn has succeeded in developing a universal boring tool with sintered chip breaking geometry. The tool offers high process reliability due to its good chip control.

The cutting edge geometry extends far into the corner radius of the insert. This ensures chip control even with small infeed settings. The geometry can be used universally for different material groups and is suitable for internal, face, copy and back turning.

In addition to the geometry, Horn optimized the carbide blanks of the inserts to have greater rigidity and an even more stable cutting edge area. The coolant supply has also been revised. The new insert is compatible with numerous types of 105 tool holders. Horn offers the inserts as standard in three lengths (15.0 mm, 20.0 mm and 25.0 mm) and in carbide grades TH35 and IG35. The corner radius is 0.2 mm. The tool is suitable for use from a bore diameter of 6 mm. The wide range of applications for the inserts goes hand in hand with their cost-effectiveness, as the price of the new Supermini is similar to that of the standard insert without geometry."

Performance in Real-World Use
Early adopters of the new Supermini generation report significant improvements in chip behavior and process reliability. Components previously prone to entangled swarf now produce fine, manageable chips that no longer interrupt machining cycles. Tool life remains in line with conventional inserts while delivering the added benefit of reduced operator intervention.

Applications and Flexibility
Because the new sintered chip breaking geometry performs well across material groups—from steels to stainless alloys—it is suitable for a wide array of industries and part types. The universal design makes it ideal for internal boring in precision components where chip control, surface finish, and tight tolerances are critical.

Whether used in aerospace, medical, automotive, or general precision machining, the updated Horn USA  Supermini system stands out as a robust solution for challenging internal turning tasks.