How to Insert a Canvas into a Hacksaw
The hacksaw is used to create through cuts on dense materials made of metal, cutting slots, trimming contour products. The bench tool is made of hacksaw blade and base machine. One end of the frame is equipped with a static clamping head, a handle to hold the tool, and a shank. The opposite part consists of a movable head and a screw that tightens the cutting insert. The heads of the hacksaws for metal are equipped with slots in which the working blade is fixed, fixed with pins.
The frames are made in two forms: sliding, allowing you to fix the working canvas of any length, and solid.
Each type of material has its own cutting blade.
- Hacksaw blade for metal represents a narrow metal strip with thin teeth placed on it. Frames are made outwardly similar to the letters C and P. Outdated models of frames were equipped with wooden or metal handles, which were placed parallel to the blade. Modern models are made with a pistol type handle.
- Hacksaw blade for working with wood. The most common carpentry version of the product. It is used for processing and cutting plywood, various in density of wooden building materials. The design of hand saws is specially equipped with a beveled work surface, teeth are located on the side of the blade.
- For work with concrete the blade is distinguished by larger cloves on the cutting edge. Equipped with carbide brazed metal. Thanks to this, it becomes possible to saw concrete structures, foam blocks, sand concrete.
- For processing metal products blades with a pitch width of about 1.6 mm are used, up to 20 teeth are located on a file 25 mm long.
The greater the thickness of the workpiece, the larger the cutting teeth should be, and vice versa.
When processing metal products with different hardness indices, files with a certain number of teeth are used:
- angular and other steel. 22 teeth;
- cast iron. 22 teeth;
- hardened material. 19 teeth;
- soft metal. 16 teeth.
In order for the file not to get stuck in the workpiece, it is worth pre-wiring the teeth. Consider the principle of wiring.
- The width of the cut is greater than the thickness of the working canvas.
- Hacksaw files with a tooth pitch of about 1 mm should be made in a wavy layout. Each pair of adjacent teeth must be bent in different directions by approximately 0.25-0.5 mm.
- A plate with a pitch of more than 0.8 mm is bred by the corrugated method. The first few teeth are on the left side, the next teeth on the right.
- With an average step of about 0.5 mm, the first tooth is moved to the left side, the second is left in place, the third is to the right.
- Plate with a large pitch of up to 1.6 mm. each tooth is retracted in opposite directions. It is necessary that the wiring end at a distance of no more than 3 cm from the end of the canvas.
GOST 6645-86. a standard that establishes requirements for the type, size, quality of saw blades for metal.
This is a thin, narrow plate with holes located at opposite ends, on one side there are cutting elements. teeth. Files are made of steel: X6VF, P9, U10A, with hardness HRC 61-64.
Hacksaw files are divided into machine and manual, depending on the type of work.
The length of the plate is determined by the distance from the center of one hole to another. The universal hacksaw file for hand tools has the following dimensions: thickness. 0.65-0.8 mm, height. 13-16 mm, length. 25-30 cm.
The standard value of the blade length is 30 cm, but there are models with an indicator of 15 cm. Short hacksaws are used when the standard large tool is not suitable for work due to size, as well as for performing filigree types of work.
GOST R 53411-2009 sets the blade configuration for two types of hacksaws. Files for manual equipment are available in three sizes.
- Unary 1 types. The distance between the through holes is 250 ± 2 mm, the file length is not more than 265 mm.
- Unary 2 types. The distance from one hole to another is 300 ± 2 mm, the plate length is up to 315 mm.
- Double the distance is 300 ± 2 mm, the length of the working surface is up to 315 mm.
The thickness of a single plate is 0.63 mm, double. 0.80 mm. The height of the file with a single set of teeth is 12.5 mm, for a double. 20 mm.
GOST determines the tooth pitch values, expressed in millimeters, the number of cutting elements:
Video: How to Insert a Canvas into a Hacksaw
- for a single plate of the first type. 0.80 / 32;
- single second type. 1.00 / 24;
- double. 1.25 / 20.
The number of teeth varies for longer instruments. 1.40 / 18 and 1.60 / 16.
For each type of work, the value of the angle of the cutter can change. In the process of processing metal with a sufficient width, rather long cuts are achieved: each saw blade removes sawdust filling the chip space until the tip of the tooth comes out completely.
The amount of chip space is determined by the pitch of the tooth, the front angle, the rear angle. The rake angle is expressed in negative, positive, zero values. The value depends on the hardness of the workpiece. A file with a zero rake angle has an efficiency lower than a rake angle with a value greater than 0 degrees.
When cutting the hardest surfaces, saw files with teeth that are pointed at a large angle are used. For soft products, the indicator may be below average. Hacksaw blades equipped with the most pointed teeth are the most wear-resistant.
The type of saw is classified into professional and home tools. The first option has a rigid structure and allows you to work at angles of 55-90 degrees.
A home hacksaw does not allow to make a high-quality smooth cut even with professional blades.
The second criterion for choosing a hacksaw blade is the material from which the product is made.
The diamond-coated tool is used to cut abrasive and brittle materials: ceramics, porcelain and others.
The strength of the file is provided by the hot heat treatment procedure. The saw blade is divided into two hardening zones. the cutting part is processed at a temperature of 64 to 84 degrees, the free zone is exposed to 46 degrees.
The difference in hardness affects the sensitivity of the product to the bends of the blade during work or the installation of the file in the tool. To solve this problem, a standard was adopted that regulates the indicators of efforts applied to manual equipment. The force on the tool should not exceed 60 kg when working with a saw with a pitch of teeth less than 14 mm, 10 kg is calculated for a cutting product with a pitch of teeth more than 14 mm.
Saws made of carbon steel are marked with the HCS mark, they are used for working with soft materials, they do not differ in resistance, they quickly become worthless.
HM alloy steel cutting tools are more technologically advanced, like alloy chromium, tungsten, and vanadium sheets. By their properties and service life, they occupy an intermediate place between carbon and high-speed steel files.
High-speed products are marked with the letters HSS, they are fragile, high price, but more resistant to wear of cutting elements. Today, HSS canvases are replaced by bimetallic files.
Bimetallic products are abbreviated as BIM. Made of cold rolled and high speed steel by electron beam welding. Welding is used to instantly join two types of metal while maintaining the hardness of the working teeth.
How to choose?
When choosing a cutting product, they are guided, inter alia, by the type of tool.
Manual hacksaws are equipped on average with single type 1 blades marked HCS, HM. The length of the file depends on the length of the tool frame, the average is in the region of 250-300 mm.
For a mechanical tool, files with any marking are selected depending on the surface being machined. The length of the cutting double blade from 300 mm or more. Mechanical equipment is used in the processing of a large number of workpieces with a length of 100 mm or more.
For mini hacksaw
Mini hacksaws work with blades no more than 150 mm. Mainly designed for convenient and quick cutting of wooden materials and metal products of small diameter, work with blanks, along a curve.
Before using the tool, it is worth installing the blade correctly in the equipment.
The installation method depends on the design of the tool mounting system. If the heads are equipped with slots, the web is inserted directly into them, stretched a little if necessary, and fixed with a pin.
To make it easier to insert the file into the clamping head, you can pre-lubricate the element with technical oil. If there is a sharp load on the file, you will have to periodically inspect the mount, check the degree of tightness of the pin so that the blade does not fall out of the clamp during the sawing process.
Installation of the cutting product in a hacksaw of lever type is carried out by the method of extending the lever, donning the blade, returning the tool frame to its original position.
Properly stretched blade when you click your fingers on the surface of the file produces a slight ringing and slight vibration. It is strictly forbidden to use pliers or a vice during the tensioning of the file. Slight misalignment or bending leads to damage to the cutting edge of the file or its complete breakdown.
The installation of one-sided blades requires utmost attention due to the direction of the cutting elements. Attach the file so that the teeth look towards the handle of the equipment. The translational movements when cutting products are performed on their own. It is not recommended to put the blades with teeth in the opposite direction from the handle, this will not allow to carry out the planned work and will lead to a jam of the file in the material or damage to the blade.
How is a cut made?
During the process of processing metal with a hand hacksaw, you need to stand behind the workpiece clamped in a vice. The body is located in a half-turn, the left leg is pushed forward, the push leg is left behind to adopt a stable position.
The cutting blade is placed strictly on the cut line. The angle of inclination should be in the range of 30-40 degrees, it is not recommended to cut exactly in a vertical position. The inclined position of the case allows you to make a smooth cut with minimal occurrence of vibration and noise.
The first impact on the material is made with little effort. The blade must crash into the product so that the file does not slip and there is no risk of tool breakage. The process of cutting material is carried out in an inclined position, the free hand is located on the product, the worker makes pushing movements of the hacksaw forward and backward.
The retention of the workpiece is carried out with gloves in order to avoid slipping of material and the possibility of injury.
You can get acquainted with the intricacies of choosing hacksaws for metal in the next video.