Metal cutting with a hand-held saw also called a hacksaw, is a method of chip cutting. The surface quality after cutting has the smoothness as well as the accuracy achieved. So cutting by a hacksaw is often used in the roughing stage of processing embryos from mechanical products in the form of bars, ingots, … for the subsequent operations. In today’s article, I will give you an overview of the hacksaw and the construction of a hacksaw things. Do not let you wait any longer, let’s find out now.
Parts of a portable saw
The general structure of a hacksaw includes:
- The frame is a flat steel bar-shaped into a U-shape to hook the saw blade. There are two types of saws, fixed and adjustable. A movable example can accommodate different types of saw lengths.
- The saw blade is mounted on the two tangent heads of the saw frame, through two sets of latches. Pink ears (nuts) are used to take apart and adjust the tension and slack of the saw blade.
Handles made of wood have a suitable shape.
Saw blades are usually made of tool steel carbon or by wind steel, tool steel alloy.
Saw blades usually have a length of 0.6 – 0.8mm, a width of 12 – 15mm, and a range of 250 – 300mm.
The two ends of the saw have two small holes (about 2.5 – 3mm) to thread the latch when hooked to the frame. Along the edge, people cut each sharp tooth called sawtooth. There are two types of saw blades: one has a row of teeth, and the other has two rows of teeth.
In terms of structure, a saw blade is a cutting tool with multiple saws; each sawing is a cutting edge.
For easy material cutting, it is necessary to open the saw circuit (to reduce friction between the saw blade and the material). There are three ways to open the saw circuit:
- Open-loop: open alternating, one tooth tilted to the left alternating with one tooth tilted to the right. This method is rarely used, sometimes used to open the chainsaw.
- Open medium circuit: one tooth inclined to the left, one tooth straightened, one tooth tilted to the right. This method is used a lot, but only to open the chainsaw.
- For small saw blade to cut metal, we open the saw blade in a step shape, every few teeth are left, some teeth are right, creating a uniform wavelength.
Classification of saw blades
There are two ways of classifying saw blades:
- Based on the sawing method to divide the hand saw blade and the machine saw blade. Hand saw edges are less than 1mm thick, and machine saws are more abundant than 1mm.
- Based on the tooth pitch, it is divided into three categories:
Firstly, small teeth with a tone of 0.8 – 1mm, used to cut thin sheets and tubes with a thickness of less than 1mm.
Secondly, medium tooth type with 1.25mm pitch used to cut steel and cast iron.
Finally, the large tooth with 1.6mm pitch for machines of all kinds.
How to hook a saw on a frame
Loosen the nut or pink handle to allow the movable mandrel to recede. Put the two ends of the saw blade into the two grooves of the mandrel and the movable mandrel, so that the tooth angle is facing toward the movable mandrel. At the same time, adjust the hole on both ends of a saw blade to coincide with the hole on the mandrel and thread the retention latch. Turn the nut or pink handle to tension the saw blade. When stretching, the saw blade should not be too loose or too tight, as both cases easily break the saw blade. So when straining, you need to adjust the saw blade moderately. If you use your finger to flick the saw blade, it will be enough to make a sound.
(Note: clamp the saw blade so that the blade direction is in the course of the working stroke when you saw.)
Above, I have shown you about the hacksaw, the constructions of the hacksaw and the operations. Once you’ve got yourself the best hacksaw, it’s essential to learn the process and how to use it. I hope this article has helped you a bit.