STS Line tool holders are crafted in Italy by Semar, a mechanical company that has been operating for over 30 years. Continuous technological updates and a certified production process are among the main characteristics that have led some of the leading manufacturers in the sector, such as Biesse, Denver, and Bottero, to rely on it.
Certified Stainless Steel
To ensure the highest quality and consistency over time, only **certified stainless steel** is used. This is far better than the industry-standard steel tool holders that are often waterproofed with a thin surface coating like niploy or black oxidation. STS Line cones are therefore **stainless to the core** and not just on the surface.
In a salt spray test, the STS line requires more than 36 hours to develop a skin-deep oxidation type, which is easily removed. Coated cones, however, once scratched, can develop irreparable corrosion.
Technical Superiority
Hardness from Core to Surface
STS Line cones have a consistent hardness of **54 HRC** all the way to the core. Unlike coated cones that might reach a higher surface hardness (up to 60 HRC), their core is very soft, barely reaching 30 HRC. STS tool holders are as strong and resistant inside as they are outside.
100% Rectified for Highest Precision
STS Line tool holders are rectified at the very end of the production process to ensure the **highest precision** on the market. Black-Oxide cones cannot be rectified, compromising their precision due to heat treatment deformations.
Superior Tolerance
STS Line tool holders offer the best precision available on the market, with an h6 shaft centering tolerance (**0.016 mm**). The tolerance of competing holders ranges from h7 to h8 (0.021 mm – 0.025 mm).
Cones with a damaged coating can compromise the precision and safety of the spindle.
Super Reliable Pull Studs & 100% Traceability
Every STS line pull stud lot is tested and released only if the break load exceeds **26000N**, which is more than double that of competitors. In addition, all tool holders and pull studs are identified with a serial number, allowing the entire production process to be traced from the initial steel bar to the final grinding.
Available for the Most Popular Machines
The product range is expanding daily to be compatible with the most popular machines, including:
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Click here to learn more about STS Line vs Black Oxide cones