What a Hacksaw Consists of
Saw (hand saw for metal). tool, the purpose of which is to cut thick sheets of profile, round and strip metal and to cut groins, splines, cutting / trimming workpieces along the contour, as well as other works. The hand-held hacksaw includes a hacksaw blade and a frame (machine). At one end of the frame is a fixed head with a handle and a shank. And on the other. a movable head with a nut for web tension and a tension screw. In the heads, the hacksaw for metal has slots: a hacksaw blade is inserted into them, attached with the help of pins.
Frames for hacksaws are made sliding, which allow you to fix the blade of different lengths, and one-piece.
To extend the hacksaw, it is necessary to bend the knee until the rivet is removed from the cutout, and then shifted. The rivet is inserted into another notch, then the knees are straightened.
A machine having a mobile holder includes a square with a handle. On it you can fix and move the holder in the desired direction.
Canvas for hacksaw for metal: what is it?
Hacksaw blade. a narrow and thin steel plate with 2 holes and with teeth on one edge. Cloths can be made of steel of the following grades: X6VF, P9, U10A, the hardness of which is HRC 61-64. Depending on their purpose, the canvases can be machine and manual. They are inserted into the frame with the teeth forward.
The length (size) of the hacksaw blade can be determined by the distance available between the centers of the holes allotted for the pins. Hacksaw blades are almost always used, designed for hand hacksaws with a thickness h. 0.8 and 0.65 mm, a height L. 16 and 13 mm, a length L. 250-300 mm.
The work of the hacksaw blade differs in the working conditions of the cutter itself, for this reason there are other values of the angles. When cutting metal with a large width, it is possible to obtain cuts of considerable length: each tooth of the blade will remove chips, which should fill the chip space until the tip of the tooth comes out completely from the cut. The amount of chip space will depend on the step S of the tooth, the front angle Y and the rear angle A.
Depending on the degree of hardness of the metal being machined, the rake angle available on the hacksaw blade can be negative, positive and zero.
The cutting efficiency of a blade having a zero rake angle will be lower than that for which the rake angle is greater than 0 °.
To cut harder materials, use canvases, the angle of sharpening of the teeth of which is greater. And for the purpose of cutting soft, this indicator should be less. wear-resistant are paintings with a larger angle of sharpening.
The required number of teeth of a hacksaw blade for different metals
For the purpose of cutting metals, in most cases, hacksaw blades are used, the pitch of which is 1.3-1.6 mm, and on a length of 25 mm there are 17-20 teeth. The thicker the cut workpiece, the teeth should be larger, and on the contrary, the thinner the workpiece, the smaller the teeth of the hacksaw blade. For metals of different hardness, canvases with such a number of teeth are used: angular, strip and hard steel. 22, tool steel, cast iron. 22, hardened steel of medium hardness. 19, mild metals. 16.
Video: What a Hacksaw Consists of
300mm metal hacksaw: working with tools
In the case of cutting with a hand hacksaw, at least 2-3 teeth should be used during operation (simultaneous cutting of metal). To avoid pinching (seizing) in the metal of the hacksaw blade, the teeth must be parted.
Tooth set-up is performed so that the width of the cut, which was done with a hacksaw, was slightly greater than the thickness of the blade itself. This can prevent jamming in the section of the canvas and greatly facilitates the process.
Hacksaw blades having a tooth pitch of 0.8 mm (a 1 mm pitch is also permissible) should have a wavy tooth layout, i.e., every 2 adjacent teeth should be bent in opposite directions by about 0.25-0.6 mm.
A blade for a hacksaw for metal, having a tooth pitch of more than 0.8, is bent along the tooth (the so-called corrugated bend). With such a divorce, 2-3 teeth are moved to the left and 2-3. to the right. With an average step, one tooth is taken to the left, the second is not taken, the third is to the right. With a large step, one tooth is removed to the right, and the second to the left. Tooth wiring is appropriate for paintings with a pitch of 1.6 and 1.25 mm.
It is necessary that the wiring of the hacksaw blade be completed at a distance from the end of no more than 30 mm.
Preparation for work
Before starting work with a hacksaw (a hacksaw), it is necessary to firmly fix the processed material in a vice. The degree of fastening of the material in them should correspond to the growth of the employee. After that, a hacksaw blade is selected in accordance with the size, shape and hardness of the metal being cut.
If the rafters are long, then hacksaw blades having a large tooth pitch are taken, in the case of short ones, a fine tooth pitch should be used.
A hacksaw for metal (photo above) is installed in the slot of the head so that the teeth are not directed to the handle. However, initially the end of the web is inserted into the fixed head, after which the position is fixed using the pin tab, and then the second end of the web is placed in the slot of the pin, secured with a pin. The canvas is pulled by hand without much effort (the use of a vice, pliers is unacceptable) by rotation of the wing nut. A 300 mm hacksaw is kept away from the face.
If the skew is slightly skewed, the tightly stretched fabric and with increased pressure, the slightly stretched fabric causes an excess, and a kink can occur. The degree of tension of the web should be checked by lightly pressing a finger on the side of the web: the tension is sufficient if the web does not bend at all.
During metal cutting using a manual hacksaw, the vice becomes steadily, freely and straight, half-turn with respect to the axis of the workpiece or vice lips. The left leg is slightly advanced forward approximately along the line of the workpiece and rested on her body. The feet should be placed so that they form an angle of 60-70 degrees (there should be a certain distance between the heels).
Hand position (grip)
It is possible to consider the worker’s position to be correct if the right hand with a hacksaw, which is set in its original position (on the jaws of a vice), bent at the elbow, will form a right angle between the elbow and shoulder parts of the hand.
The handle must be grabbed with the right hand so that the handle rests against the palm of your hand. It is wrapped around 4 fingers, and the thumb should be placed along the handle on top. The fingers of the left hand should grab the movable head of the hacksaw and nut.
During cutting with a hacksaw, like filing, strict coordination of efforts should be observed, which consists in the correct increase in manual pressure. The hacksaw should move strictly horizontally. The machine is pressed with both hands, however, the greatest effort is made with the left hand, and the reciprocating movement of the tool is mainly carried out with the right hand.
Cutting includes 2 moves:
They do not press the hacksaw at idle, as a result, the teeth only slide. And in the case of a working stroke with two hands, they provide light pressure, and the tool moves linearly.
Rules for working with a hacksaw
Follow these instructions when working with a hacksaw:
- Cutting short workpieces should be done on the widest side. In the case of processing of rolled channel, T-profiles and corner profiles, it is recommended to change the position of the workpiece, and not to carry out cutting on the narrow side.
- Hacksaw metal cutting should be carried out without jerking, smoothly, slowly, you need to do no more than 40-60 double strokes in 1 minute.
- All hacksaw blade should participate in the work.
A hacksaw handle for metal is the best helper if you need to cut metal in hard to reach places.