Working as a professional restaurant cook is the ultimate culinary workout. Every day, you're guaranteed to get in your reps thanks to the never-ending need to slice and dice bushels of vegetables, break down dozens of whole chickens, fillet tubs of fish, and then cook for hours on end during service. Even working as a professional food writer and recipe developer, it's nearly impossible to get in the same amount of practice as I did working in a restaurant kitchen; the vast majority of home cooks would likely have an even harder time finding the time, budget, or desire to do the same.
Unfortunately, this can become a real issue with knife sharpening. At Serious Eats, we've long advocated using a whetstone, which, when done properly, is one of the best ways to sharpen a knife. But there's a lot riding on the "when done properly" part. To get a knife truly sharp on a whetstone requires a significant amount of muscle memory—it's up to you to maintain a consistent sharpening angle relative to the stone. If you can't hold the same angle when grinding your blades on a stone, they won't have a consistent edge, and they'll be much duller as a result.
Maintaining a consistent sharpening angle doesn't just take a lot of practice to do well—it also requires upkeep. When I worked in restaurants and had a need to sharpen my knives at least once a week, I was able to develop the skill and keep it—and my knives—sharp. Yes, I still cook a ton for work, but the volume of food that I prepare is so much lower that I don't need to sharpen my knives as often. When I do take out my whetstone, I can feel the uncertainty in my hands, that lack of instant recognition when my angle isn't just right.
For most home cooks without professional cooking experience, it's an even bigger challenge. Unless you commit to a near-daily sharpening regimen, it's difficult to become proficient at knife sharpening on a whetstone, let alone be able to maintain that skill. I mean, can you tell me right now without consulting any tool what a 15-degree angle looks like compared to an 18-degree one? I can't.
That's where I've found these little angle sharpening guides to be helpful. The kit comes with a variety of angle options ranging in one-degree increments from 10 to 20 degrees; you can also stack them to create more angle options. You attach the small plastic wedges to the end of your whetstone with a rubber band, and they sit there as a reminder of the sharpening angle you're trying to apply.
It's not a perfect system: the angle guides don't ride along with your knife to keep you honest with each stroke, and they prevent you from using the area of your whetstone underneath where they're attached, which will eventually lead to uneven wear on the stone if you don't use a stone fixer to level it off (though you should do this anyway). But they're inexpensive and, I've found, good enough to get me back on track after a long sharpening hiatus. And while they alone aren't enough to instantly make you great at using a whetstone, they'll at least mitigate one of the bigger challenges to a quality sharpening job.
For anyone interested in whetstone sharpening who suspects they won't be pumping (kitchen) iron on a daily basis, having these little doodads on-hand is kind of a no-brainer.