Hand saw grip, sawing posture, pressure speed
1. Grip method: Hold the handle of the saw fully with the right hand, and lightly support the front of the saw bow with the left hand.
2. Posture The standing position and body swing posture during sawing are basically similar to filing, and the swing should be natural.
3. During the pressure sawing movement, the thrust and pressure are controlled by the right hand, and the left hand mainly cooperates with the right hand to straighten the saw bow and the pressure should not be too large. When the hand saw is pushed out, pressure is applied to the cutting stroke, and the return stroke does not cut and does not add pressure to pull back naturally. The workpiece will break with less pressure.
4. Movement and speed The sawing movement generally adopts a small up and down swinging movement. That is, when the hand saw is advanced, the body leans forward slightly, and when the hands are pressed toward the hand saw, the left hand is raised and the right hand is pressed down; when returning, the right hand is raised and the left hand naturally follows. For straight sawing that requires the bottom surface of the saw seam, linear motion must be used. The speed of sawing movement is generally about 44 times/min. It is slower to saw hard materials and faster to saw soft materials. At the same time, the sawing stroke should be kept uniform, and the speed of the return stroke should be relatively faster.
Saw cutting operation method
1. The clamping of the workpiece The workpiece should generally be clamped on the left side of the lead for operation; the workpiece should not extend out of the jaws too long, and the saw seam should be about 20mm away from the side of the jaws to prevent the workpiece from vibrating during sawing; The saw seam line should be kept parallel to the side of the jaw (so that the saw seam line is in the same direction as the vertical line), so that it does not deviate from the scribed line with the control saw seam; the clamping should be firm, and at the same time, it is necessary to avoid deformation and damage to the workpiece clamp. noodle.
2. The installation of the saw blade The hand saw can only cut when it is pushed forward. Therefore, the saw blade should be installed so that the direction of the tooth tip faces forward. If it is installed backwards, the front angle of the saw blade will be negative, and it will not be able to saw normally. When adjusting the tightness of the saw blade, the wing nut should not be screwed too tightly or too loosely. When the saw blade is too tight, the force on the saw blade is too large, and if the force is slightly improper during sawing, it will break down; if it is too loose, the saw blade will be easily twisted during sawing. , It is also easy to break the segment, and the saw seam is easy to skew. The degree of tightness can be used to move the saw blade with the hand to feel the hardness. After the saw blade is installed, make sure that the plane of the saw blade is parallel to the center plane of the saw bow, and must not be inclined or twisted, otherwise, the saw seam will be easily skewed during sawing.
3. Starting sawing method Starting sawing is the beginning of sawing work. The quality of sawing will directly affect the quality of sawing. If the sawing is not correct, the saw blade will jump out of the saw seam and the workpiece will be roughed or the sawtooth will crack. There are two types of saws: far saws and near saws. When starting the saw, the thumb of the left hand leans against the saw blade, so that the saw blade can be sawed in the required position correctly. The stroke should be short, the pressure should be small, and the speed should be slow. The starting angle θ is about 15°. If the starting angle is too small, the sawing will not be stable, especially when the sawing is close, the sawtooth will be caught by the edge of the workpiece and cause cracking) but the starting angle should not be too small, otherwise, the number of teeth in contact with the workpiece at the same time is relatively small. It is not suitable to cut into the material. It is often easy to deviate from the sawing for many times, so that many saw marks are sawed on the surface of the workpiece, which affects the surface quality.
4. In general, a long start is used (the sawtooth is not easy to get stuck and it is convenient to start the saw). If the hand saw is not well grasped, the sawtooth is stuck by the edge of the workpiece. At this time, the hand saw can also be used to pull the saw backward. From the saw saw to a depth of 2 ~ 3mm. During normal sawing, all the effective teeth of the saw blade should participate in the sawing in each stroke.