How much pressure to use on a whetstone?
- dcole Nov 29, 2010 11:08 AM
I've been using one for a while and have gotten great results from them, but I think I might be putting too much pressure on the knife when I sharpen them - I am not putting a lot, but I am also not babying it. So to the people on here who are pretty knowledgeable, how much pressure do you guys put on the knife against the stone? Just enough to create a grind against the stone or a little more?
Wow, tough one. Mark Richmond from Chefknivestogo said he put no more than 1 pound of force in one of his videos. On the other hand, Dave Martell said he lean on his knives pretty hard and put a lot of pressure. I think the general consensus is that you do not exert more force than you can control the angle. As you put more and more force down, you will start to lose your ability to keep up a consistent angle. You want to able to hold a consistent angle. Also the rule is that you put more pressure on coarse stones (<1000 grits) and less pressure on fine stones (>1000 grits).
I put a decent amount of pressure on the forward stroke, and little / none on the back-stroke. I think "enough" pressure is enough that you can raise a burr on the knife without spending all day, especially on the coarser stone.
Do you put your fingertips right on the edge of the blade, or further up?
I use a fair amount of pressure but I have no way to put a number on it. I think the advice above about not using any more force than you can control is excellent advice and i've never heard it put like that.
I put my fingers of my non dominant hand on the portion of the edge that I am working on.
In general, I apply the most pressure with a coarse stone, and let up on subsequent stones. I also generally use lighter pressure for the last few passes of each stone than I do for the first few passes. The last few passes on each stone I'm applying basically no pressure at all.
I actually went and pressed into a scale with the amount of pressure I use to set a bevel. Came to about 15 lbs, occasionally up to about 20, which was a little more than I expected. Once the bevel is set, I let up on pressure to just a few pounds.
I can't add much about double-beveled western knives, because I've always used single beveled Japanese knives, so all of the following only applies to Japanese single beveled knives.
When I started sharpening Japanese knives I made the mistake of using too little pressure for the first few years. In the beginning I used what I would say was approximately two or three pounds of force, and now would say I use over ten, with better results. That said, I must give two disclaimers: #1- I cut myself in a horrible accident when I was young when my knife stuck on a water stone that wasn't completely flat, and I was using too much pressure applied too close to the corner of the bezel. I was doing other things wrong too, but the end result was that I almost cut off half my finger. It was the only time I've cut myself badly in 18 years of using knives daily, and I learned a valuable lesson: As you get better you can apply more pressure as long as it's with proper technique. The only people who can use maximum pressure are the ones with the best technique and the most experience. If you use too much force with bad technique you can seriously injure yourself, so increase gradually. #2 - If you put too much pressure in the wrong place with a single beveled Japanese knife, specifically over the corner of the bevel causing it to round, you will not have great success. The best knife sharpeners I know have knives with bevels that look like they were cut with a CNC mill. Japanese knives with sharp, clean angles cut better and hold an edge longer than those with rounded lines, so when you're learning the primary focus should be on making everything square rather than speed. IMHO, if you're not an expert it's easier to grind it down perfectly flat with a little less force because the knife tends to lay flat on it's own. When you start to add a lot of force it's harder to feel if you're pushing in the wrong place or allowing your angle to change slightly. Many people also worry about pushing too hard while forgetting about the length of their stroke. Using long strokes is as important to your efficiency as the amount of pressure you use. In my experience with Japanese knives I think you can achieve good results with medium pressure until you start using Hon-Yaki knives, which are much harder, and require good technique combined with fairly high pressure to get the job done in a reasonable amount of time.