First, the structure and angle of woodworking tools
Good woodworking tools should be sharp, durable and easy to grind.
Sharpness and durability are both opposites and interdependent. Sharp and durable refers to the maximum retention under appropriate sharpness. The cutter is too sharp, the cutting edge radius is too small, the strength is insufficient, it is easy to curl and become dull, and it is not durable. Enough is enough.
1. structure
Traditional woodworking tools are attached to the steel structure, one side is iron and the other side is tool steel, forged together.
There are also a few steel clips, such as a double-edged axe, where steel is sandwiched between iron.
The cutter with this structure has high labor intensity and high labor cost. Steel-bonded tools are sharp, durable and easy to grind. It is easy to use and is an ideal hand tool.
Nowadays, woodworking tools are often all steel, which is easy to make. There are also high-speed steels (also called Fenggang and Bai Gang). The blade with this structure is sharp, but its toughness and grindability are often not ideal.
2. Angle
The angle of planing is generally 30 degrees, shoveling and chiseling are generally 35 degrees (hardwood can be larger and cork can be smaller), flat shovel is generally 30 degrees, and single-edged axe is generally 35 degrees.
Second, the choice of grinding disc
1. Classification of millstones
Sharpening is divided into rough grinding, medium grinding and fine grinding, and grinding stones are also divided into rough grinding, medium grinding and fine grinding.
Coarse grindstones and medium grindstones generally use oilstones, and fine grindstones generally use slurry stones (bluestones and special blue bricks).
100-320 mesh oilstone is suitable for coarse grinding, and 400-800 mesh oilstone is suitable for medium grinding.
2. Requirements for high-quality oilstone:
Sand iron: When the tool is pushed on the grindstone, it must have resistance and cannot slip. After grinding a few times, you should see a lot of black iron powder coming down, so sharpening the stone is quick.
Hardness and wear resistance: After grinding with water for several times, there should be no grindstone particles in the water, only black iron powder. This kind of grindstone can be used for many years, and the grinding tool has a good finish.
Moderate thickness. The coarse effect is not good, and the fine speed is too slow.
The inferior whetstone is either too hard or too soft. If it is too hard, the self-sharpening is poor, the particles are not sharp, and it is easy to strain the blade, resulting in scratches on the surface of the blade and cracks in the blade. Moreover, the grinding speed is extremely slow. If it is too soft, it will be consumed too quickly, and the grindstone will soon sag and cannot be used. At the same time, don't be superstitious about high-grade oilstones. This kind of oilstone is very professional, with strong pertinence and extremely harsh conditions of use. High cost may not achieve the best results.
Novices recommend the use of green carbon oilstone, which is soft in texture, strong in cutting, good in self-sharpening, not easy to block, suitable for both soft and hard tools, and affordable, but has the disadvantage of large consumption and easy to sag.
3. Use of oilstone
Do you use oil or water when sharpening a knife with an oilstone? Different views have puzzled me for a long time.
The answer is: you can use oil or water, which is more convenient to clean. Carpenters generally use more water.
Adding a small amount of detergent (or soapy water) to water can enhance the adsorption capacity of oilstone, make it easier to stick to the knife, and form a dense water film on the knife body, thus reducing the requirements for the cleanliness of the knife.
The newly bought oilstone is very absorbent, and many people use oil bubbles. It is also good to use oil to grind this kind of grinding disc all the time, but after replacing it with water, the effect is not good for a while, and it will be fine after a long time.
The oilstone should be fully soaked before use, and the surface should be washed with water after grinding for a period of time.
4. Grouting stone
Natural pulp stone is used for fine grinding. Requirements: not hard. At around 1 degree, fingernails can be slotted. The liquid produced by adding water to a good refiner has a certain viscosity, like rice soup.
The rough grinding blade is very good, and it is very sharp after fine grinding.
Fine grinding can also use fine oilstone, woodworking tools can be ground to 1500 mesh, and mirror finish can be polished to more than 2000 mesh.
5. Dressing of millstones
Depressed oilstones should be leveled in time. It can be polished on flat cast iron plate, granite and glass, or it can be polished on a relatively flat and rough cement floor with fine sand and water. .