Properly set a metal blade
Metal hacksaw is a hand tool, which is used for cutting of profile metal and pipes. The simplest metal hacksaw consists of a machine and a hacksaw blade. The machine, in turn, consists of a frame into which on one side is inserted a handle that has a device for fixing the blade, and on the other side, a device for fixing and adjusting the tension of the blade. Tension device, on the one hand has a slot for the insertion and fixation of the web, and on the other hand, a screw with the ram which is made and the tension of the web.
Metal hacksaw blades vary in width, length, thickness, spacing and height. Using of one or another blade depends on thickness, hardness and form of material to be cut. Blade manufacturers ensure that you can find a blade just right for the material you need to cut, whether it’s aluminum, copper, bronze, or even plastic. blade dimensions, namely the length, width, tooth size and steel grade, can be found on the purchased hacksaw blade.
How to set the blade in a metal hacksaw?
As shown in the first diagram in this article with the teeth facing down (if the blade is single sided) and the teeth pointing forward from the handle. When you are sawing you apply downward and forward pressure. the teeth of the hacksaw should be facing down and forward in exactly the same way. To install, release the tensioning screw, remove the old blade from its pins, put on the new one and tighten it so much that the blade tinkles with the click of your fingernail as if it were a string. The main thing here is not to over tighten and tear the blade. You will find the optimum tensioning by experimentation.
The tension is made with the turnbuckle on the adjuster, that is, by twisting the turnbuckle you will tighten the blade. So when tensioning a hacksaw blade you have to find a happy medium. Also, make sure the blade is set straight with no twists, as twisting will cause an uneven cut during cutting.
How to saw?
Since you were wondering how to set the blade, it does no harm to give you some advice on how to use the metal trimmer blade as well. Grasp the handle of the hacksaw with one hand (right hand if you are right handed or left handed if you are left handed) and take the vertical edge of the arc of the hacksaw opposite to the handle with the other hand. Place the blade on the trimmer blade. Point the blade strictly in the direction of the cutting line. Make the angle of the hacksaw small. The blade should almost lie on the workpiece, usually at an angle of 30-45 degrees. This way there is less vibration, less noise and the trimmer line is smoother. Cutting across the material, at an angle of 90 degrees, is worthwhile only in urgent cases, for example, when turning the cutting line. The flatter you need your trimmer blade to cut, the less angle it should slope.
The first movements should be done with little effort, so that the blade cuts into the material and does not slide sideways away from the cutting line. With smooth, gradual movements, press the hacksaw firmly against your workpiece as you move forward and release pressure when you return to the starting position. Once the blade has grip on the material, you can work with all your might.
The range of motion is maximum, from blade edge to edge, without the arc of the hacksaw hitting the workpiece. No need to “tread on the spot”. so you will quickly erase the blade in one area and have to throw it away, because you can’t use a damaged blade. Keep the arc of the hacksaw straight, do not let it bow in different directions. Cutting direction corresponds to the plane of the arc of the hacksaw, so chattering is contraindicated. Also, the blade breaks easily if the hacksaw jerks to the side. The material properties of the blade are such that it holds very well the longitudinal tensile force, but is very brittle in bending.
Cutting with a hacksaw on a curved line
A metal hacksaw is also valuable because it lets you cut in almost any curved line. To cut in an arc without stopping the forward motion of the hacksaw, align it perpendicular to the face of the workpiece material (t.е. angle of 90 degrees) and gradually turn the arc of the hacksaw smoothly so that the blade follows the planned line. Yes, the line for the trimmer cut is always sure to mark with anything. a pencil, marker, scratch nail. The main thing is to be able to see it when you work. Turning the blade must be done as gently and smoothly as possible, otherwise it will break; turns are an extreme for a hacksaw blade on metal.
If you have to make a sharp turn, say 90 degrees, you’ll have to practically “stomp on the spot” while continuing to saw and smoothly turn the arc of the hacksaw, stepping back periodically so as not to get too far from the turn, while using the side of the material that is external to the piece to turn the blade.
To cut the inside corner, first you need to drill a straight line for the trimmer with a thin drill just over the width of the blade, slide the blade into this groove and cut further with a hacksaw. In general, practice will show you how to do it. Nothing complicated here.
The picture below shows another way to use a hacksaw for metal. For this method, you need to reset the blade by turning it 90 degrees.
Hacksaw blades for metal
Metal hacksaw blades are one of the most unreliable elements of the whole range of consumables for tools. Of course much depends on the technology of working with metal and the skills of using a hacksaw, but first of all you need to be able to make the right choice of blade. Today, we will talk about the choice and types, as well as learn how to easily change a hacksaw blade.
Types of hacksaw blades and their design
Do not forget that the production of a working hacksaw blade is carried out in accordance with the established standards in GOST 53411-2009. The information in this normative and technical documentation defines two main groups: for machine cutting and for hand cutting. It is worth considering that the machine hacksaw blade on metal is purchased very rarely, because such equipment is very rarely used. The following versions are produced for the handheld hacksaw:
- Single saw blade for metal with the distance between the fixing elements 250 mm. With a total length of 265 mm. This version is suitable for tools which are used when there is no need for high output.
- Single versions with a distance of 300 mm between the two fixing elements. Total length is 315 mm.
- For higher productivity the double hacksaw blade is installed. This version has the same length as the previous one.
Pitch and pitch are regulated, because this parameter determines many of the performance characteristics.
In the manufacture of such a product a variety of alloys can be used, which largely determines the main performance characteristics. The following alloys are the most widely used:
Hacksaw blades with tungsten carbide sputtering have recently become quite common, as they are characterized by increased wear resistance. It is worth considering that the sputtering can have the most different colors, on sale there are blue variants of execution, the usual steel is dark gray.
The tungsten hacksaw blade under consideration is characterized by the fact that at high hardness of the working surface the structure is characterized by high sensitivity to bending load. That’s why in case of careless metal cutting such a product will not be able to last for a long time.
To achieve a high strength manufacturers can conduct a thermal treatment. The following should be taken into account:
- The main part of the product is characterized by the hardness of the surface layer of about HRC 44-46.
- Depending on the type of material used in the manufacture, the hardness of the tooth varies in the HRC range from 64 to 67. This indicator is characteristic of alloyed alloys. High-speed steel is characterized by the fact that the hardness of HRC in the range of 73-78 units.
Do not forget that significant differences in hardness make the product sensitive to bending. The tool is designed for different loads, it must not exceed 60 kg at a pitch of 1.4 mm, as well as 10 kg at a tooth pitch of less than 1.4 mm.
Quite a large number of varieties of such a product determines that with the selection of a suitable performance variant does not arise serious problems.
Metal hacksaw. Home workshop
Metal hacksaw can be useful not only for some metalwork, so it is quite a versatile tool in the workshop of the home handyman. The blade of such a hacksaw has very fine teeth, which allows working with many materials other than metal. Plastic, foam plastic, chipboard, PVC, laminate, plexiglass and even wood can be successfully cut with a metal saw. Edges of material cut with a metal saw are very smooth. It is desirable that the metal saw has the ability to set the blade at an angle of 90 degrees. It allows you to cut large-sized sheet materials, while the lack of such an opportunity limits the depth of cut to the height of the hacksaw itself. Some models have the possibility of fixing the blade at a 45° angle. Hacksaw blades are thin, narrow and quite brittle, so bending them is inadmissible. That’s why the workpiece must be clamped firmly in a vise. Otherwise, any displacement of it while working with a hacksaw can break the hacksaw blade. In general, it is not so easy to saw with a hacksaw. The most important thing. is to make sure that the saw goes back and forth evenly. It should not wiggle from side to side and the blade should not sag. Tensioner must provide a quick change of saw blades and their secure attachment. The tensioning device of the hacksaw shown on the picture is very convenient. The front is hinged and can be pivoted to tension the blade by turning the ratchet at the top. The blade is inserted into the sabre with the toothing “on its own”. The tension of the blade must be sufficiently tight to eliminate any vibration that would immediately greet a breakage. Do not overtighten the leaf, because the holes on the edges greatly weaken the leaf and it can break right there. The hacksaw blade cannot be restored, but its fragments can be used for making different wood cutters or simply inserted into a handle and used as a mini-hacksaw for cutting of not very thick materials.
Metal saw blades are one of the most unreliable elements of the whole range of consumables for tools. Of course, much depends on the technology of working with metal and the skills of using a hacksaw, but, first and foremost, you need to be able to make the right choice of blade.
National Encyclopedia of Building ProfiDom.com.ua tells about the choice and types of blades for hacksaws and the correct method of working with them.
Types of hacksaw blades
- The existing GOST R 53411-2009 “Metal hacksaw blades” establishes two types of such tools. for machine and hand cutting. We will not touch the first, but the latter are available in three basic sizes:
- Single, with a distance between the fixing holes of 250±2 mm, with a total length of the blade not more than 265 mm;
- Single, with the distance between the fixing holes 300±2 mm, with a total length of the blade not exceeding 315 mm;
- double, with the distance between the fixing holes 300±2 mm, with a total length of blade not more than 315 mm.
In this case, the thickness of the blade s single version. 0.63 mm, double. 0.80 mm. Single toothed blade height is 12,5 mm and double toothed blade height is 20 mm.
GOST also regulates the pitch of teeth P, mm, and their number z, which for the first type of blade are respectively 0.80/32, 1.00/24 and 1.25/20. Owners of the “longer” hacksaw blades can also use hacksaw blades with the parameters 1.40/18 and 1.60/16 in addition to the above mentioned ones.
According to the brand of material used for the manufacture of blades for metal hacksaw blades are made of tool steels:
In specialized trading networks the so-called diamond blades with surface spraying by titanium nitrides or other high-temperature metals are widespread. Such blades can be easily distinguished by color: ordinary steel blades are dark gray, and sprayed blades can have different coloring. from bright orange to blue (depending on the manufacturer).
There are also blades with a so called tungsten-carbide spraying, but they are extremely sensitive to bending stresses despite their very high hardness. Therefore, when cutting metal their durability is insignificant.
High durability of metal hacksaw blades is ensured by appropriate heat treatment.
There are two zones with different hardness values on the surface of the blade: directly near the teeth it ranges from НRС 6467 for alloy tool steels to НRС 7378. for high-speed steels (for diamond blades this parameter reaches НRС 8284), and in the rest zone. НRС 4446.
Significant hardness differences confirm high sensitivity of the product to bending stresses, which is why the standard also limits the maximum force applied to a hand saw. It must not exceed 60 kg when working with blades with tooth pitch less than 1.4 mm and 10 kg for blades with tooth pitch over 1.4 mm.
How to choose a blade for a hacksaw
- Type of a hand hacksaw for metal, to be exact. distance between fixing holes. Better if it is changeable, then any size of hacksaw blade will do for work.
- Strength limit of the metal to be cut. If the tool is supposed to use for cutting of soft, plastic metals, such as copper, aluminum and so on, it is necessary to use a plywood backing., it is reasonable to have a hacksaw blade with the lowest hardness. X6VF steel can be accepted as material; imported blades have the HCS designation on the side plane. For cutting stronger metals, blades made of high-speed steel (the corresponding imported designation is HSS) are suitable.
- Thickness of metal to be cut and quality of cutting surface. Foreign practice recommends as a criterion of choice the parameter PPI. number of tooth tips which falls on each inch of the blade length. For example, for thin metals where a very smooth cut surface is required, PPI24 is considered the correct value. If the performance factor is more important to the user than quality, it should be PPI
- Quality of tooth separation. GOST R 53411-2009 provides three variants. separation on each tooth, through tooth, or through two adjacent through one unset tooth. In the latter case, the outermost plane of the blade must protrude beyond the basic one by a distance (0.150.25)s, and in the rest. by (0.650.90)s. Since the setting is made in both directions, the actual distance measured with a caliper should be twice as large as the above.
How to correctly set the teeth of a hacksaw?
Quite a common question is how to set the teeth of a wood hacksaw. If they are offset in one line, the cut is narrow and the working part gets stuck in one place. In this case there is a rapid heating of metal, due to what it begins to expand. To make a good job of setting the tines we recommend the use of special machines. The recommendations for the work to be done are as follows:
- The saw is clamped in a vice to hold it securely. You can eliminate the likelihood of damage to the working part by using plywood as a pad.
- All cutting elements are bent through one by one to the recommended angle.
When considering how to make a pitch on a hacksaw, we note that several elements deflected at a larger angle can cause a complication of sawing.
Every kind of material has its own cutting blade.
A metal hacksaw blade is a narrow metal strip with thin teeth placed on it. Frames are made in appearance similar to the letters “C”, “P”. Older frames had wooden or metal handles, which were parallel to the blade. Modern models are made with a “pistol type” handle.
Hacksaw blade for wood. the most common joinery variant. Used for cutting and sawing plywood, various densities of wooden building materials. Hand saws are specially equipped with a beveled working surface, with teeth on the side of the blade.
For working with concrete, the blade is distinguished by larger teeth on the cutting edge. Equipped with tungsten carbide inserts. Thanks to that it becomes possible to cut concrete, foam blocks, sand-crete blocks.
Blades with a pitch width of about 1,6 mm and up to 20 teeth on a 25 mm long saw blade are used for metal products.
When processing metal products with different hardness, saw blades with a certain number of teeth are used:
In order to prevent the saw from getting stuck in the workpiece, it is worth doing the teeth setting beforehand. Let’s see what principle is used for setting.
10 Best Hacksaw Blades 2021
- The width of the cut is larger than the thickness of the working blade.
- Hacksaw blades with tooth pitch width of about 1 mm must be set in wavy pattern. Every pair of adjoining teeth should be bent in different directions by about 0,25-0,5 mm.
- Plate with a pitch of more than 0.8 mm is corrugated. The first few tines are set to the left side, the next tines to the right.
- At an average pitch of about 0.5 mm the first tooth is set to the left side, the second tooth is left in place, the third tooth is set to the right side.
- Plate with coarse pitch up to 1,6 mm. each tooth is withdrawn in opposite directions. It is necessary that the setting ends at a distance of no more than 3 cm from the end of the blade.
Tips for use
Before using the equipment, it is worthwhile to correctly install blade in the equipment.
Installation method depends on the design of the fastening system of the tool. if the heads are equipped with slots, the blade is inserted straight into them, tightened slightly as necessary, and secured with a pin.
Installation of the cutting product in the lever-type hacksaw is done by extending the lever, putting the blade on, returning the tool frame to the initial position.
A correctly tensioned saw blade produces a slight buzzing noise and slight vibrations when snapping fingers on the saw blade surface. It is strictly forbidden to use pliers or vise during the tensioning of the saw. Minor tilting or twisting leads to damage or complete breakage of cutting edge of the saw blade.
Installation of single-sided blades requires extreme attention because of the direction of the cutting parts. It is necessary to fix a saw blade so that the teeth look in the direction to the handle of the equipment. Progressive movements when sawing products made from yourself. It is not recommended to put the blade teeth in the opposite direction from the handle, it will not allow to make the planned work and will lead to jamming the saw in the material or breakage of the blade.
For miniature sabre saws
Mini-saws work with blades of less than 150 mm. Mainly designed for comfortable and sharp sawing of wood and metal products of small cross-section, work pieces, on the curve.
What kind of plywood is necessary for sawing with a jigsaw??
Practice shows that the best material for working with a hand jigsaw is birch plywood with a thickness of 2 to 8 mm. It is available, easy to handle and highly durable.
To create small details or “dense” openwork patterns it is more appropriate to use three-layer plywood up to 3 mm thick. It can be easily sawn and is quite strong. It is much less likely to ruin the curve you sawed out with another jamming of the blade.
Choosing the material for crafts, pay attention to the fact that the plywood was even and without a large number of knots. Examine the end face for the presence of air chambers, their presence indicates an uneven application of glue. It is better to refuse from such low-grade plywood, otherwise you can not avoid a large number of chips, which will spoil the appearance of the product.
Read also: How to repair a soldering iron at home
Hand hacksaw for metal: the main characteristics, the criteria for selecting a quality tool
A hacksaw designed for working with metal alloys is a tool that many owners have in their arsenal. It is hard to imagine doing many household chores without this tool.
Nowadays, the range of this type of saw is very wide, and there is usually no difficulty in choosing a tool. The main thing is to consider some parameters and characteristics of metal saws.
Saws for metal are presented in the market in two variants. electric and manual tools. The handheld solution can be used for any job, as this hacksaw is very compact and lightweight. Another advantage is its low cost. The only disadvantage is the considerable effort and time required in the work process.
Types and uses of the tool
The purpose of this tool is considered sawing products made of durable metals, cutting grooves and seams, trimming metal workpieces, etc. д. You can also cut metal alloys, ceramics, plastic, styrofoam, wood, and organics, among other materials with a hacksaw.
There are three varieties of metal saws:
- Home-use models are the most affordable and popular option, suitable for simple household tasks. Characterized by ease of use. In most cases, such devices are equipped with screws and a handle made of wood, which is located longitudinally to the cutting blade.
- Professional-grade hacksaws. can work for a very long time, creating high-quality cuts. Professional hand saws for metal are often equipped with a comfortable and durable handle and allow you to set the blades at a certain angle, which is required to create cuts of unusual shape.
- “Handle”. has a special shape, resembling a staple. This allows the use of this type of sabre saws in hard-to-reach places. Such a tool is excellent for inside cuts.
The tool has a fairly simple design. Handheld models resemble a staple, with a tensioned blade clamped between the ends. Tool consists of a frame and saw blade with teeth.
Each of the tool’s elements has its own features and characteristics:
- Handle is very important in the work process. It relates to the convenience of long-term use. The best variants of the handles are two-component, equipped with special inserts of soft but durable rubber. Handle is on the top or side of the sabre saw.
- The frame that secures the saw blade. It can be made of various materials. High-strength composite frame is used for cutting hardwood. The design of this element is directly related to its application. So, if you regularly have to saw metal in hard-to-reach places, it is better to buy a device with adjustable inclination of cutting blades or a small frame.
- Blade is a thin steel strip. This is the thinnest and most delicate part of the tool. That is why you need to be as careful and careful with the fasteners in the process of work. Sloppiness will cause the blade to break. There are wedge-shaped cutters (tines) on this part. Choosing a saw, you should pay your attention to whether the teeth of the cutting blade have been hardened, which can increase the life and performance of the tool. Blades with small teeth are used for cutting hard metal products, while soft structures are processed with large cutters. Bimetal or hardened versions are recommended. In the frame, the blades are installed so that the teeth are in the opposite direction from the handle.
How to work with a manual hacksaw
Working with a hand saw for processing metal alloys does not require special knowledge and skills. But there are certain rules:
- Do not forget about the importance of correct positioning of the master’s torso in relation to the cutting areas. The arm should be bent at a right angle, and the feet slightly turned. This way you can increase stability.
- Before installing the cutting blade, it must be straightened to the width of the frame. Then the element is secured with the nuts. A correctly adjusted blade avoids all kinds of vibrations while working. But over-clamping often results in failure of the part. It’s best to adjust the tension the first time you tighten the nuts.
- It is necessary to hold the instrument with both hands when sawing. The movements should be steady and even.
- The workpiece to be treated is recommended to be fixed by a special vise. This minimizes the chance of blade breakage.
So you should choose the tool according to the following features:
Changing Hacksaw Blades The Correct Way
- The shape of the teeth. varies depending on the slope of the cutting element at the front.
- Tooth pitch. the characteristic determines the thickness and strength of the materials with which the tool can work. The choice depends on the size and material of the workpiece. Two or three teeth should be used.
- Blade size. depends on the size and volume of the workpieces. The average length of the saw blade varies from 290 to 700 millimeters. The blade must be smooth, clean and hold its original shape. There must not be any cracks or traces of rust on the surface.
- Handle. try to avoid hollow variations. The tool can break even under slight pressure. Hold the saw in your own hand when selecting. The palm of your hand should fit snugly around the handle.
- Price. the cost of a metal saw depends on the material and type of blade, as well as the configuration of the teeth. It is undesirable to choose too cheap models, as well as to rely on famous brands.
When choosing a good hacksaw, do not forget to replace the saw blades in time and use the tool intelligently.
Hacksaw blade for metal. How to choose and install? |
Hacksaw blades for metal. one of the shortest-lived elements of the entire range of consumables for tools. Certainly much depends on technology of work with metal and skill of use of the hacksaw, but first of all it is necessary to be able to make correct choice of the blade. Today, we will talk about the choice and types, as well as learn how to easily change the hacksaw blade.
Saws Blade Types
GOST R 53411-2009 “Metal hacksaw blades” specifies two types of such tools. for machine and hand cutting. We will not touch the former, but the latter are available in three basic sizes:
- Single, with the distance between the fastening holes 250±2 mm, with a total length of the blade not more than 265 mm;
- Single saw blades with the distance between the fixing holes of 300±2 mm with the total length of blade not more than 315 mm;
- Double, with the distance between the fixing holes of 300±2 mm, with the total length of the blade not more than 315 mm.
Thickness of single blade. 0,63 mm, double blade. 0,80 mm. The single toothed blade has a height of 12,5 mm and the double toothed blade a height of 20 mm.
GOST also regulates values of tooth pitch P, mm and their quantity z, which are 0,80/32, 1,00/24 and 1,25/20 accordingly for the first type blades. Owners of “longer” hacksaws, in addition to the above, can also use hacksaw blades with the parameters 1.40/18 and 1.60/16.
According to the grade of material used for the manufacture of blades for metal hacksaw blades are made of tool steels:
Range of Russian-made hacksaw blades is limited by this fact, but specialized trading networks have widely spread so called diamond blades with surface spraying by titanium nitrides or other high-temperature metals. Such blades can be easily distinguished by their color: ordinary steel blades are dark gray, and sprayed can have different colors. from bright orange to blue (depending on the manufacturer).
There are also blades with the so-called carbide-tungsten dusting, but they are extremely sensitive to bending stresses, though their hardness is very high. Therefore, when cutting metal, their service life is extremely low.
High durability of metal saw blades is ensured by an appropriate heat treatment. Two zones with different hardness values are distinguished on the surface of the blade: directly at the teeth it ranges from НRС 6467 for alloy tool steels to НRС 7378. for high-speed steels (for diamond blades this parameter reaches НRС 8284), and in the rest zone. НRС 4446. Significant hardness differences confirm the high sensitivity of the product to bending stresses, which is why the standard also limits the maximum force to be applied to a portable hacksaw. It shouldn’t exceed 60 kg when working with blades with tooth pitch less than 1,4 mm and 10 kg. for blades with tooth pitch over 1,4 mm.
The principles of blade selection
The durability of the hacksaw blade is also affected by the quality of the coating. For domestic tools the more common coating is Chem.Ox.Prm., less often you may encounter a tool with nitro enamel coatings like HC-25 or HC-132. It should be remembered that under prolonged loads, when the saw heats up, the enamel can give cracks.
When choosing a good-quality angle grinder it is worth paying attention to the uniformity of tooth pitch: in high-quality products this parameter should not exceed 45% of the pitch of the teeth on a length of 10 mm. The quality of the product can be also estimated by the parameter of equal height of the teeth: the difference in the adjacent peaks should not exceed 0,10 0,15 mm, which can be checked with a micrometer or a depth gauge.
How to mount the blade on a hacksaw on metal?
The method of installation is determined by the design of the mounting system on the hacksaw itself. In the case of a threaded clamp, the saw blade is placed on the corresponding tab, tensioned slightly and then secured with the wing nut. With sharp changes of load on the hacksaw such fasteners should be checked periodically. With hacksaws with a lever-arm type device, installing and changing is simplified: simply pull out the lever on the opposite side to the handle of the hand saw, insert the blade, and return the lever to its original position.
When properly tightened, the blade should make a slight buzzing and slightly vibrating noise. During operation such a blade should not change its direction of travel under load.
For one-sided blades it is important to position the blade in the correct direction. Their inclination should be away from the handle. Most workers make the main working movement away from themselves, when they cut the metal. Reverse motion is intended only for returning the hacksaw to its original position. When attempting to cut metal and while idling, the tooth geometry, which is not suitable for such loads, will pull the tooth away from the base, and the blade may break as a result. this phenomenon is especially characteristic for diamond blades.
Recently so-called bimetallic blades (designation. BIM) have become popular, when a strip of high speed steel is welded on the basic band of hardened constructional steel like steel 45. Here it is quality that counts: in the case of saw blades made in China the metal grade is most often not guaranteed (and neither is the quality of the welding), and therefore when working with hard metal it is not uncommon for bimetal blades to delaminate.