However, when the DMT diamond angle grinder I hoped to get (I like the grinder on the diamond surface) never arrived, I could never give up the idea of sharpening the knife. Although it sounds like a waste of time (my knife is not very valuable, but I like it very much). I once sharpened some knives (all kitchen knives and small folding knives are sharp, but the blades are extremely ugly), so I chose the cheapest one from a pile of blunt knives and started my sharpening process.
Needless to say, when you have a folding knife with a few hundred dollars in your hand, your attitude is much more correct and looks smoother than a kitchen knife with a dozen dollars. When grinding the third and fourth knives, I was delighted to find that the experience has accumulated slowly and the blade has begun to become smooth and beautiful! Finally, with the cooperation of the right tools, I grinded a knife with smooth blade, uniform width and sharp as a razor!
Now write down these feelings and share them with friends who also love knives-"Cold Guardian", and ask the majority of knife friends to correct their criticisms.
I. Tools
As the old saying goes, if you want to do a good job, you should sharpen your tools first. In order to achieve the same effect as using a fixed angle sharpener, a suitable sharpening tool is necessary.
It has always been thought that the wider the grindstone, the better (the grindstone on the market is about 5 cm-8 cm). At present, it is considered in practice that the diamond surface with a width of about 1CM-2CM and a length of about 10CM has the best grinding effect. The reason is that the whole edge line of the tool is rarely straight, but mostly has a certain curvature. When sharpening a knife, the edge line can't be completely attached to the wide grindstone. My sharpening gesture is to sharpen the knife with one hand, which makes an angle of about 45 degrees with the grindstone (the reason will be mentioned below), which shows that the relatively narrow grindstone is easy to control the blade. Another important point is that the finest grindstones on the market are about 800 mesh. Under this mesh, the grindstone wears quickly, so it is necessary to constantly adjust the contact between the blade and the grindstone to adapt to the wear of the grindstone. And the diamond-faced grindstone (including ruby grindstone) I use, because its surface is basically not worn, so it is not necessary to change the contact surface between the blade and grindstone frequently. Therefore, it is best for qualified friends to use the grindstone strip on the surface of the diamond. It is not easy to wear, which will make you feel much more relaxed when sharpening the knife, and it is easier to quickly grind the blade with good flatness.
My tools from rough grinding to mirror polishing are diamond assorted file -Gobo diamond grinding bar-ruby grinding bar-metallographic sand skin.
1: King Kong assorted files-suitable for big moves. Its surface is extremely rough, and the effect of eating meat is obvious and refreshing. It is suitable for changing and cutting the edge of the tool, and it can handle almost any hardness of steel.
2: (Gobo) Diamond sharpening stick-suitable for rough grinding. A convenient tool for sharpening knives. Its basically wear-free diamond surface is the main reason why I like to use it. Its advantages are no need to add oil and water, and convenient cleaning; It is convenient to carry and eat meat, and you can sharpen your knife easily and quickly when you travel. The tool made of diamond grinding bars can meet daily use, but it needs to be finely polished to be beautiful.
3: Ruby grinding rod-suitable for fine grinding. Grinding rod made of ruby particles, the mesh number is about 1500. It also has a feature that the surface is not easy to wear. Add a few drops of water when grinding. The blade ground with it can already reach the point of cutting paper into silk.
4: Metallographic sandpaper-suitable for polishing. It is the last tool to polish the blade into a mirror effect without losing its sharpness. When in use, cut it into strips with appropriate width and length, and put it on a hard strip (such as a steel tape measure) for use.
Two. Action article
Now that we have the right tools, we need some skills. Comfortable and correct posture is the guarantee of grinding quality. I will write down my posture in detail below, but it may not be suitable for you, for reference only.
Sit at a desk or dining table (you will save a lot of energy. If you stand or squat, you will feel that this is more like a punishment than an exciting job, because your waist will not straighten up quickly. Put the grinding rod (tool) in front of you at a 90-degree angle. In order to prevent the table from being worn, newspapers or cloth can be laid in advance. But don't be too thick, in that case, you will find that too thick newspaper or cloth will become your burden-the tip of the knife will keep stabbing these things.
Hold the grinding rod firmly with your left hand and fix it to avoid moving it during sharpening. Hold the handle of the tool in your right hand, and the tip of the tool is in the upper left corner, making an included angle of 45 degrees with the grindstone. When grinding the left blade (the position when the tip of the blade is facing up and the blade is facing away from itself, the same below), the thumb is pressed on the blade, and the other four fingers hold the handle; When grinding the right blade, the thumb is pressed on the anti-slip groove on the back of the blade, the index finger is pressed on the blade body, and the other three fingers hold the handle. This posture can fix the sharpening angle of the tool more easily. The reason why one hand holds the knife is because there are two forces acting on the knife when both hands are used, and the force is unbalanced, which leads to uneven surface of the blade and prone to convex surface.
Feel is very important when sharpening a knife. Force evenly, not so quiet. If it feels smooth, it is that the plane of the blade has been completely attached to the grinding tool, which is the best time. If it feels astringent, it means that the blade is only partially polished on the grinder. At this time, it is necessary to stop the action, observe the polished part of the blade, and then adjust the polishing angle until it is confirmed that all blade surfaces are attached to the grinder for polishing. At this time, the best way to write down the grinding angle is to remember the distance from the back of the knife to the grinding tool, and then slowly advance and retreat the blade while grinding until it grinds to every part of the blade. Every grinding tool adopts this posture. Here is a trick: when grinding the left blade, imagine grinding the abrasive tool, and when grinding the right blade, imagine grinding the abrasive tool, which will make it easier to control the angle. When grinding, it is necessary to observe the blade frequently to determine the grinding degree and control the grinding quality.
One more thing to note is that straight edges are easy to polish, so I won't talk about it. When encountering a curved blade (such as a drop-shaped blade tip), the following treatment should be taken: do not change the grinding angle of the blade, that is, do not change the angle between the horizontal direction of the blade and the grinding tool, then slowly lift the blade from the position of the handle, and then slowly withdraw the blade until it reaches the blade tip. When encountering a concave blade (such as the root of MOD MKV blade), it is necessary to treat the surface of the abrasive tool into an arc to match the concave blade, and the posture remains unchanged. When grinding, the journey must not be long, but short. When I grind, the stroke is only about 5mm, so the angle is easy to control.
Finally, the sharpness of the tool can be judged in the following ways:
1: Face the blade to the light source, slowly rotate the blade body, and carefully observe the reflection of the blade. An unpolished blade will have white spots or linear reflections, while a sharp blade does not have these phenomena.
2. Gently scrape the blade with your thumb, feeling hairy and rustling is a sharp performance. If it feels smooth, it is not sharp.
3. Hold a piece of paper (such as practice paper, no matter how thick it is) with your thumb and forefinger, and then cut it radially with a knife. A sharp knife should cut the paper in half easily. If it is torn by the blade instead of cutting the paper, it means that the knife is not very sharp.
4: Shave off the hair on your arm with a knife. If it is easy to shave off, the knife is sharp.
When you grind a sharp knife with a beautiful blade, how intoxicating is the satisfaction that your efforts will eventually pay off!
Basically, my experience is so much, and I hope everyone can correct me more. I also hope that my poor works can play a role in attracting jade, and I also hope that everyone will come up with their own experience in using and maintaining knives and provide dinner for the world's knife friends.
General rules for sharpening knives:
1, no matter what knife you grind or what tool you use (Lansky, Spyder. ,
Grinding stone ..... whatever), the first requirement of sharpening a knife is to keep the angle of the blade fixed when grinding, which requires practice, but there is one trick that all veterans know. Before grinding, paint the blade area of the knife black with a strange pen, then bring it here and grind it a few times, and then check the blade area. If the angle is correct, the black color will be completely worn off. If not, adjust the angle after observing the marked area by yourself, and remember the feeling after grasping the angle. This method is suitable for both novice and veteran, because different knife angles are different, even professional sharpeners may have to adjust their feelings according to different knife angles.
Speaking of this, there is a misunderstanding that everyone can think about. Is it necessary to keep the original cutting angle when each knife leaves the factory? From the collector's point of view, there is no doubt about it. But from the user's point of view, I think it is debatable. I usually change the knife angle according to my own knife habit, so that the knife can play the greatest role in my hands, but the premise is that "even if I want to change the knife angle, I still have to keep the changed knife angle unchanged."
2. When you can fix the blade angle when sharpening the knife, you begin to enter the most critical procedure: the degree of grinding. Sharpening a knife is the process of thinning and grinding off the blade material to make a new sharp blade, so the function of grinding a stone depends on it. Rough grinding is to make sharp edges by the above process, and fine grinding is to remove burrs produced in the rough grinding process, and then further strengthen the function of fine grinding. Therefore, the key to sharpening the knife is the rough grinding procedure. If you have been grinding badly, you should strengthen it from here. Generally speaking, if the blade has no edges and corners and needs to be trimmed or thinned, we usually grind it roughly from a 600-grain grindstone and polish it according to the principle of 1. To what extent?
Key point: Grind until the edge on the other side has burrs (or flash). Deburring means that you really thin the blade and create a new sharp area, because your grinding surface has reached the edge. At this point, turn the blade surface and grind it again according to the same principle until the other blade is again. {Pow _ burr (Some masters only remove the burr on one side to complete the sharpening process (the same is true for the chisel sharpening knife), and then sharpen it from the other side next time).
3. If you confirm in step 2 that you have finished 80% of the sharpening work (it is very beneficial to touch the blade vertically by hand at this time), the rest is the deburring work.
You can use 1000 or 1200 grit grindstone to deburr. After moderately grinding the edge for about ten times (compared with step 2), check the edge surface. You should deburr on the other side of the edge, but this burr is much smaller than the burr produced in step 2. Turn it over in the same way, grind it ten times and then turn it over.
Next, with a small force (almost the weight of the knife itself), slightly raise the angle of the blade (about 5 degrees), lightly grind it for three or four times, then turn the knife surface and grind it three or four times according to the same principle. Okay, you got it.
It ... A sharp knife for deburring.
The above process is just a general rule, and individuals can add or subtract according to their own habits or different types of knife steel, but this is probably the case in procedure. If you are still not good at grinding (unlikely), start from the second step and wait until the burr is really done before proceeding to the next step.
The next step is the process of light. Just adding abrasive particles to leather (or cloth wheel, etc.). ) mirror the blade (which has a great influence on sharpness), but the main point is not the same as that mentioned above. It is realized by slightly increasing the blade angle by moving the back of the blade forward (because light also has the function of removing fine burrs). It should be noted that not all knives need light. Generally, some serrated blades are left for cutting ropes, such as paper, and the blades used in the push-out mode, such as peeling apples and shaving, have excellent results after polishing. Please decide for yourself according to your own needs. (Note: In "The Wonderful Use of Survival Knives", Tuoba Jiuqing once proposed: Single-edged knives (single
Bevel) pressure cutting, double-edged knife broaching. It has the same effect as the above principle, because usually the tools that need to be polished are cut with a small edge angle by pushing or pressing force (such as peeling). )
After the above procedure, I believe even a novice can sharpen a very sharp knife. The only difference is that in the second step, the veteran should be able to keep sharp edges and corners and complete it in less time. But as long as everyone has the perseverance and patience to do the second step, we will certainly be able to grind a beautiful and sharp knife. In my personal experience, a knife that has been deburred but not polished is easy to scrape off leg hair and hair, and cut off A4 paper or suspended hair, but I don't know about shaving, because my knife is not used for shaving, and it is easy to shave my hands and legs, but it is absolutely unnecessary to shave my face with a knife in front of a mirror (except for a safety razor) to avoid accidental shaving and disfigurement.
5. Finally, discuss with you how to keep the sharpness of the blade. Joe Talmaci is sharpening the knife in the sharpening center.
The FAQs article points out that due to the progress of steel and heat treatment technology of the current cutter, the blade will not wear quickly after being used for a period of time, but the end of the blade will bend to the left or right due to the user's force application method, and the user may feel that it is not as good as just grinding. At this time, the sharpness of the blade does not need to be re-polished, just take an iron sharpening stick (the kind commonly used by pork vendors) and brush the blade a few times from left to right. Because the hardness of grinding iron is not very different from that of knife steel, the process of this brush is only to realign the edges.
However, it is not like grinding the material of the blade in the aforementioned sharpening process. Therefore, we should pay special attention to the use of iron sharpening sticks, not ceramic or diamond sharpening sticks (these two sharpening sticks are real sharpening rather than rearranging the blade angles). It doesn't matter how many grooves there are on the iron sharpening stick.
The method of brushing is to use the left hand to grind the iron bar, and brush the blade at an angle of about 20 degrees from the vicinity of the handle to the tip of the knife. When brushing, the force is very small, almost the weight of the knife itself. After each brush, brush again on the other side. In this way, after five to ten cycles, the blade angle of the knife should be straightened, and the knife can be as sharp as new. brush
Whether the blade is forward or the back of the knife is forward depends on personal habits.
Joe suggested that whether it is a soft kitchen knife or a hard knife like ATS34, this sharpening step should be carried out frequently, which can not only keep the knife sharp, but also shorten its life, because it is not necessary to sharpen it frequently. However, if Steeling can't restore the sharpness of the knife, it means that the blade is really dull, and the knife must be sharpened according to the above steps 1 to 4 to restore the sharpness of the knife.
The above theory of Steeling has been verified by practice, and I agree with it very much, which is also very effective. But it should be noted that,
Smoothing is of course a good way to keep the blade, but using cloth wheel and grinding and polishing is another good way. It has no rough grinding function, but it can guide the positive blade angle and get the mirror blade. The disadvantage is that it is much more troublesome than steelmaking, so you can choose according to your preference.
Use. In short, don't sharpen your knife and don't miss the woodcutter.
Maintenance), which will shorten the service life of your favorite knives (especially high-priced folding knives such as Sebenza), and finally become toothpick-shaped, and the more you grind the corners, the more difficult it is to grind.
6. Summary:
Some of the above articles are paraphrased from Joe Talmadge's articles in KnifeCenter's frequently asked questions about sharpening knives, plus the simple general rules compiled by my younger brother after collecting various sharpening materials in the past. The detailed process may require everyone to explore and establish their own unique knife method. But interestingly, these theories are also what I have asked some knife workers.
When discussing, we will always mention the common ground, so if both eastern and western cultures find it useful, I believe it should be useful to everyone. Briefly describe the sharpening skills with several formulas, hoping to help everyone: "Burr, deburr and polish." OK,
Here you are.
In addition, I forgot to tell you that if you are a novice, in addition to the key points in the above article, please pay special attention to the step of reducing strength in the process of fine grinding and polishing. This step is taken for granted from my previous training in Sangbae Kim, but it may be the same for people who are not familiar with it.
The key process, in short, the lighter the grinding force, the smaller the burr and gradually disappear (if the action of reducing the force is skilled and rational, even if it is a medium-thickness sharpening, everything can be done). If you just want to sharpen a knife for ordinary daily life (not as sharp as a razor), then the strokes can improve the blade angle in the last few fine grinding. If you want to scrape, don't change the angle of the blade, the force is getting lighter and lighter, and it will be amazing to increase the angle of the blade until the last few strokes of leather.
Freehand high-precision grinding skills [turn]
1, Equipment: In the absence of a fixed angle sharpener, the strip oilstone is a necessary tool for hand grinding. I used imported No.280 and No.600 oilstones, and the oilstones were knocked into short strips of about 5 cm. Knock both ends flat as far as possible, and don't leave big sharp corners, so that you can hold them steadily with your fingers. Oilstone is a consumable, and the working face will gradually sag during grinding. At this point, the grindstone must be replaced in time. A cushion with moderate hardness is also necessary. I welded two 5 cm long steel bars into a T-shape, wrapped them with tape and placed them horizontally on the table. The workpiece is placed on its corner, which is quite stable and the angle is easy to control. Just use ordinary engine oil as a grinding aid and apply it to the machined surface at any time with a cotton swab.
2. Manipulation: Manipulation is the key to polishing. Hold the workpiece firmly in the left hand, put it firmly on the pad, and put the left forearm firmly on the table, and irradiate the workpiece with enough bright light from the left side of the body. Keep the small cutting edge surface to be machined as horizontal as possible, and pull it horizontally with the right hand to obtain a high-precision polished surface. The action of the right hand is the most important. The thumb and ring finger of the right hand firmly hold both ends of the oilstone, and the middle finger and ring finger naturally stick together. The combination of thumb and ring finger is most suitable for high-precision manual work, such as motorcycle throttle control, opening a safe, holding a baseball bat and so on. The ring finger is the most important part. In addition, the grinding is mainly the horizontal swing of the forearm. When the thumb and ring finger are naturally matched, the position of the whetstone is just on the extension line of the forearm, and the up-and-down displacement of the whetstone can be controlled to a minimum during horizontal grinding. The final plane can be realized on the workpiece as far as possible, not on the arc surface. There are still two problems to pay attention to in the technique, that is, the index finger should be suspended and not placed on the oilstone. Practice has proved that it will increase the up-and-down swing of the oilstone, and one more thing is never to operate with gloves on your right hand! ! When grinding, the right hand must be sensitive at any time, and gloves will hinder the feeling. On the contrary, gloves should be worn when operating with the left hand, and the workpiece must be absolutely stable. Gloves can absorb the slight jitter of cushioning hands and reduce errors.
3. Polishing: Before polishing, stick a layer of transparent glue on the cutter body, leaving only the cutting edge, so as to avoid scratching the cutter body by misoperation. Apply proper amount of oil to the working surface and oilstone. At this time, the workpiece is parallel to the operator's body and crosses the front, while the machining surface is parallel to the desktop and the oilstone is also parallel to the desktop. The vertical angle between the oilstone and the workpiece is kept at about 30 degrees. After moderate pressure contact, the wrist remains motionless. The sliding route of the oilstone forms an angle of about 30 degrees with the parallel line of the workpiece. In rough grinding, the force along the cutting edge direction and the force against the cutting edge direction can be similar, but in fine grinding, the force can only be applied along the cutting edge direction and can only slide against the cutting edge direction. At the beginning of grinding, the oil did not change color, and the contact angle of the oilstone was not clear. At this time, we can only start with experience, not too hard. Later, after the contact surface appears black oil stain, the contact surface can be seen clearly, and then the fixed strength and stroke can be maintained. This process will last for a long time, sometimes for several hours, which will test people's patience. In this process, the relative relationship between hands must be absolutely stable. With a slight change, the working face will become round and everything will have to start all over again. If it is a new knife that has not been polished by hand, the oilstone can be directly ground to the whole working face. You'd better control the angle. If it is a polished old knife, its cutting edge is often circular, or if the cutting edge of a new knife is modified, the whetstone can only touch a very narrow line first. After continuous grinding for a period of time, the lines will gradually widen until the contact surface covers the whole cutting edge surface. In the process of polishing, it is necessary to keep a proper amount of oil, neither more nor less. Less oil will affect the polishing effect, and more oil will make people unable to see the contact surface clearly. Please ask the assistant to finish the refueling work as much as possible. If you do it yourself, it is easy to destroy the established contact surface. To repair an old knife or a very dull knife, you can start with a low-grade whetstone, and then change to a high-grade whetstone when the grinding is almost finished. The new knife can be directly installed with advanced grindstone. Another problem that needs attention is that the horizontal displacement of the whetstone on the workpiece must be maintained, and enough horizontal stroke can automatically compensate the errors in grinding, so that the blade line is straight and the horizontal drawing stroke is too short. The last edge line is curved, not straight, so pay special attention to this when repairing tools with certain defects. Also, in the initial stage of grinding, the requirements of the travel and angle of the oilstone are not very strict, but in the later stage of grinding, these two indicators must be strictly controlled, otherwise the wear marks are inconsistent, and the knife is sharp but ugly under reflection.
4. Requirements; The sharpness of the final polished knife is of course necessary. Secondly, the machined surface should be relatively flat, close to the plane, basically no arc can be seen, and the wear marks are consistent. The angle and depth of wear marks on the whole machining surface are always the same. Under the reflection, the reflection of wear marks is parallel to the edge line, rather than obliquely passing through the whole machining surface. If necessary, it can be polished moderately, but polishing will affect the sharpness, so it should be carefully considered when operating.