What is the best hardness for a knife blade?

The best hardness for a knife steel depends on several factors, including the intended use of the knife, the specific steel composition, and personal preferences. Generally, a knife blade should have a hardness that is high enough to hold a sharp edge, but not so high that it becomes brittle and prone to chipping or cracking.

In general, most knife steels have a hardness rating between 55 and 65 on the Rockwell scale (HRC). For example, many popular stainless steel knife steels, such as VG-10, have a hardness rating of around 59-61 HRC. High-carbon steels, such as 1095, may have a hardness rating closer to 55-58 HRC.

Some specialized knife steels, such as powdered metallurgy (PM) steels, can have even higher hardness ratings. For example, CPM-S90V has a hardness rating of up to 62 HRC, while CPM-3V can have a hardness rating of up to 64 HRC. These steels are often used in high-performance knives that require superior edge retention and wear resistance.

However, it's worth noting that a higher hardness rating doesn't always equate to better performance. Factors such as the blade geometry, heat treatment, and sharpening angle can all have a significant impact on the knife's overall cutting ability and durability. It's also important to note that harder knife blades may be more difficult to sharpen, and may require more frequent maintenance to keep them in top condition.

Ultimately, the best hardness for a knife steel will depend on the specific application and user preferences. It's important to choose a steel that balances edge retention, toughness, and ease of maintenance to meet the demands of the intended use.