The Preference for Full Flat Convex Knife Edges - Sharpening and Maintenance Tips
When it comes to knife grinds, the Full Flat Convex grind is by far my favorite. This grind type is renowned for its strength, longevity, and ability to spread the cutting edge evenly, thereby reducing friction and wear. It is also highly practical for knife sharpening, making it an excellent choice for both novice and experienced knife enthusiasts.
Strength and Durability of Full Flat Convex Grind
The Full Flat Convex grind is considered the strongest and most durable among all knife grinds. It is particularly well-suited for use with steels like 1055–1065, which, while not as hard as some higher carbon steels, are still capable of holding a keen edge. The convex shape allows the knife to maintain its edge over time, even when the steel is on the softer side. My katana, for instance, holds a hair whittling edge and has a thick blade compared to most pocket and kitchen knives. This thickness adds to its robustness without compromising on sharpness.
Optimizing the Full Flat Grind
While the Full Flat Convex grind is highly advantageous, there are instances where additional work may be necessary. For instance, if the steel lacks the ability to hold an edge even when tempered well, I might reprofile it to a flat grind, secondary bevel. However, with high-quality blades, I usually add a flat grind secondary bevel to see how it holds up before moving to a convex secondary bevel. The flat grind serves as a baseline to gauge the potential of the blade.
Preserving the Edge with Secondary Bevels
If the knife already comes with a Full Flat grind, I typically add a flat grind secondary bevel to assess how it performs. If it shows signs of potential improvement, I may proceed to convex a secondary bevel and compare the results. I find that a flat edge is a good indicator of the blade's potential, especially when compared to a convex edge.
Practical Tips for Edge Maintenance
While Full Flat Convex grinds are excellent, the edge can still benefit from secondary bevels. If the steel cannot hold an edge due to low tempering, poor tempering process, or suboptimal steel choice, a reprofile to a flat grind might be necessary. Meaty blades can afford to lose that amount of steel, but thin blades should be approached with caution. Hollow ground knives can also be flattened and then given a convex edge, although this decision may vary based on the specific knife and its overall design.
For kitchen knives, I often prefer a secondary convex grind. However, I do not rely on sandpaper for this task; I use stones at home and in the field. While sandpaper can be effective, stones provide a more precise and controlled edge over time. Additionally, if you need to clean a knife from heavy use, using wet and dry sandpaper can make the task easier.
Most of my knives are of above-average quality, allowing me to use thinner edge profiles with convex grinds over flat grinds. The convex profile not only reduces friction but also spreads the cutting edge more evenly, leading to a longer-lasting, more durable edge.