Three distinctive features are characteristic of band saws. They are made only of special grades of tool steel, which ensures high strength and durability of the teeth. Russian manufacturers usually use steels of categories 9XF and B2F, foreign companies give preference to the C75 series. Material hardness should not be less than 45 HRS in any case.
Cutting width of band saw blades is much narrower than for the circular saws. As mentioned above, this is an essential factor when machining precious woods and industrial wood.
Saws are able to handle workpieces of any length and diameter without any problems. A properly sharpened band saw ensures a high production output.
It must be noted that the reliability of the closed band saws can be explained by the heterogeneity of the material used for the saw blade.
The saw blade in particular is made of spring steel that has an incredible resistance to tensile and dynamic loads. High tungsten and cobalt grades of steel are used for the cutting edge. Separate parts of the band saw blade are welded together by high frequency currents. Tools made with this technology can be used to cut metal.
Preparing the tool for the job
The quality of the cutting edge inevitably deteriorates when the tool is in constant use. It becomes blunt and the width of the tooth space is reduced. That’s why wood saw sharpening and setting is an essential part of the band saw maintenance.
Note that the teeth should be set before sharpening, not vice versa.
Using the deburring machine.
Setting is the process of bending the teeth on their sides. It is necessary so that the band saw blade does not get caught in the workpiece and so that friction is reduced while working.
- With the classic method, the teeth are bent left and right in a strict sequence.
- With the deburring method, every third tooth remains in its original position. This method is optimal for appliances that are designed to cut particularly hard wood.
- In the wavy setting a separate bending value is given to each tooth. In this case, the profile of the leaf takes the form of a wave. This method is the most difficult.
Please note! When setting, do not bend the whole tooth, but only a third or two thirds of it from the top. Manufacturer’s advice is to perform the operation so that the bending range is within 0.3-0.7 millimeters. The operation is performed with the help of a specialized expanding tool.
Sharpening the saw
Elborating discs with different shapes.
Before you sharpen your circular sawblade or band saw blade, note that more than 80% of accidents with damaged tools (including their rupture) are caused by non-observance of work rules.
- The need for the operation is visually detected. Pay attention to the condition of the teeth and the quality of the cut walls (e.g., increased roughness).
- Bandsaw point wheels are selected according to the hardness of the teeth. Corundum sanding discs are necessary for tool steel tools. Bimetal saws are sharpened on borazone or diamond wheels.
- The shape of an emery wheel for band tools must be chosen according to their parameters. Cup, profile, pan, flat grinding wheels.
- Before the operation you need to unscrew the saw and let it hang in this position for about 10-12 hours.
A diagram for sharpening a handsaw in wood should take into account the following points.
- Metal removal along the tooth profile must be uniform.
- Avoid unnecessary stress on the sharpening tool. It could lead to annealing.
- Blade profile and tooth height must remain constant.
- Liquid cooling during operation must be ensured.
- There should be no burrs on the teeth.
Pay attention! Theoretical wood band saw blade sharpening instructions state that it should be done either on the front side of the teeth, or both on the back side and the front side. In real life, however, most specialists and amateur craftsmen perform the operation only on the back side, t.к. it is more convenient.
Picture shows automatic full profile sharpening.
To prepare the tool for operation, it is possible to use special sharpening tools (for example, machines with different materials and shapes of discs) or manually. Before correctly sharpening the wood saw, it is necessary to learn the basic methods of carrying out this operation.
The first method. full profile sharpening.
- It is the highest quality, the operation is carried out on an automatic machine.
- An Elbor sandpaper, chosen precisely in shape, passes the entire surface of the inter-tooth cavity at the same time as the accompanying planes of the adjacent teeth in one motion.
- No angularity is created at the tooth tips.
- The relative disadvantage of such sharpening is the need to have at your disposal the appropriate number of wheels for blades with different profiles.
The second method is sharpening the tooth flanks.
Can be sharpened manually or with a professional sharpening machine.
- After choosing a machine, it is necessary to determine the wheel to be used. As a rule, it is flat. Sharpening machines should only be used if there is a lot of sharpening to be done.
- At home, sharpening is best done with your own hands. either with an ordinary mechanical emery tool or with an engraver. During the operation, do not forget about personal protection and use gloves, a mask or special glasses.
Working with an engraver.
Band saws are cutting tools used in band saws. They are a closed band with teeth. They have a mass of their own unique advantages. The kerf of band saws is much narrower than that of circular saws: if in budget wood this fact is perhaps not essential, when cutting high-end metal and valuable wood it is. They can be used to cut any type of workpiece. Belt saws also impress with their good cutting speed. provide a high quality of cut surface. Swarf reduction through their use is an obvious thing. However, in order to sustainably experience in practice all of the above benefits of working with the tool, you need to take a responsible approach to its maintenance. Band saws sharpening, as well as their setting should be made qualitatively and in time.
Sharpening of band saws in specialized workshops is usually not expensive, but the speed and competence of the work is not always happy. Can the task be done with your own hands? Of course, if you know how to sharpen band saws correctly and have the necessary devices.
- A bit of theory: What tools are made of?
- All about teeth and sharpening angles
- Sawing finer points on band saws
- How to properly sharpen a band saw?
- Tips from the Professionals
- What kind of errors can occur in the sharpening process?
A little bit of theory: What are the tools made of??
Wood saws are usually made of tool steel (hardness 45 HRC). For production of metal goods Russian producers address to steels V2F, 9KhF, foreign producers. to C 75 and others. The teeth of these saws are “rewarded” with the highest hardness in the quenching process by high-frequency currents. Bimetal band saw is often used when working with metal: its blade is made of spring steel, but the band with teeth. of an alloy with high cobalt and tungsten. This high-speed steel is “bonded” to the base of the saw by an electron beam.
All about teeth and sharpening angles
Band saws can have different geometry of teeth: it depends on the type and properties of the material being sawed. As for tools for work with wood, they can be carpentry, dividing, and intended for sawing logs. and the parameters and shape of the teeth of each “subspecies”, respectively, are different. The angle of sharpening for band saws in wood is determined by the manufacturer based on a number of factors, but the key trend is that the harder the material, the smaller the rake angle should be.
There are two basic tooth shapes for constant pitch metal saws. standard and “positive rake angle“. Standard teeth are designed for cutting thin-wall material, with a positive rake angle for cutting metal with thick walls.
Now for the pitch. For thin-walled materials (sheet metal, pipes) use saws with small tooth pitch. otherwise there is a risk of damaging or even breaking the tooth. Thick-walled materials are best handled with a tool that has fewer teeth per inch.
To eliminate effect of resonance that provokes blade vibration, set row of saws with variable pitch.
The finer points of band saw setting
As the tool is used, the quality of its cutting edge deteriorates. That’s why setting and sharpening band saws correctly is a natural part of the working procedure.
Please note! The setting should be made before sharpening, not after!
Setting is an operation to bend back the teeth to the sides to prevent tool blade clamping and to reduce tool friction. There are three basic types of deburring:
classic. the teeth are bent to the right and left sides strictly alternately; deburring. every third tooth is left in its original position. “is used for cutting very hard materials and alloys; wavy. each tooth has a “different” value of bending, so that a wave is made out of them. It is the most difficult type of setting.
good to know! Not the whole tooth is bent but just a part of it, one-third or two-thirds from the top.
The setting values recommended by the manufacturers are in the range of 0.3 to 0.7 mm. Operation is carried out with the help of special adjustable tools.
How to properly sharpen band saws?
Proven: than 80% of tool breaks are caused by improper sharpening of band saws. The need for manipulation is determined visually. by the appearance of the teeth themselves or by the condition of the kerf walls (increased surface roughness). Circle for band saws sharpening is chosen according to the hardness of the teeth. To sharpen tool steel products, corundum wheels are used. Bimetal saws require diamond or borazone specimens. The shape of the band saw blade grinding wheel should be determined according to the parameters of the tool. It may be profiled, cup-shaped, flat, cup-shaped.
Before beginning of works it is recommended to let the saw to hang in twisted state for ten-twelve hours.
Requirements for band saws sharpening with your own hands:
Ensuring even metal removal along the tooth profile; avoiding excessive pressure on the wheel (it can lead to annealing); ensuring the preservation of the height and profile of the tooth; obligatory presence of coolant; controlling the absence of burrs.
Standard instruction for band saw blade sharpening stipulates that sharpening must be carried out either on the front surface of the tooth, or on both the front and back surfaces. But that’s the theory. In practice, many professionals, and craftsmen “perform” it only on the back surface, so, in their opinion, is more convenient.
In general, despite the mass of rules and requirements, these tools are rather unpretentious in terms of sharpening. It is possible to work with them, both with a special sharpening device for band saws, and manually; to use for processing of different shape and material of the wheels, etc.д.
Before sharpening band saws it is necessary to get acquainted with the basic ways of carrying out this operation.
Is the best quality, performed on an automatic machine. The precisely shaped Elbe wheel passes the entire interdental cavity along with the corresponding surfaces of the adjacent teeth in one motion. Elaborate shapes at the tooth base are avoided. The only disadvantage of such sharpening is the necessity to have a certain number of wheels for “different profile” saws at constant disposal.
Can be used on a professional lathe or by hand. If the preference is given to the machine tool, then, again, it is necessary to choose competently a circle. usually these are flat samples. Generally, it is recommended to turn to specialized sharpening equipment only in those cases where the amount of work is quite large. The occasional “domestic” manipulation is better to be done manually, with an engraver or on an ordinary machine. For safety reasons, a face mask or safety goggles must be worn when working.
If you have neither a machine nor an engraver in your arsenal, it is possible to sharpen band saws by the usual method of your grandfather. by wielding a file. Three or four sure motions on the back or front side of each cog, and the case, as they say, is “in the bag”. If the operation is performed regularly and diligently, the skill of good hand sharpening will quickly emerge.
Tips from the Professionals
If you have sharpened the band saw blade by means of a machine, check before you start that the sharpening blade is in the right position in relation to the tool. 2. It is very important to remove so much metal from the grooves that all microcracks are guaranteed to be eliminated. 3. If the tool has been “operating” without proper maintenance for longer than the manufacturer allows, the amount of metal removed per sharpening operation should be increased. 4. Always use a new tool as a reference to check the sharpening results. 5. The shape of the saw tooth is a parameter that has been developed and proven over the years. That is why it is a great mistake to think that a tool will cut like clockwork no matter what you do with its teeth. 6. If you follow the operating requirements, the band saw will serve you well until its width has been reduced to 65% of its original value. The width decreases, naturally during resharpening. 7. There is a totally absurd recommendation that there is no special need for deburring after machining. If you “listen to it”, the appearance of micro cracks in the blade is guaranteed. 8. Immediately after use the band saw blade should be cleaned of resin and swarf, and inspected thoroughly before sharpening. Otherwise, the risk of clogging of the sharpening discs is extremely high. And this inevitably entails a “shoddy” sharpening procedure.
What kinds of errors can occur during sharpening?
Error 1. Burnt grooves in the workpiece teeth
The reason for this is the excessive force of the grinding wheel. Rapid band dulling as a result.
Error 2. Incorrect tilting angle and imperfect shaping of the tooth flanks.
Several factors can lead to this situation:
drift of the eccentric of the sharpening device; error in setting the angle of inclination of the machine head; discrepancy in the profile of the sharpening wheel.
And that’s all. Now you know how to properly sharpen band saws and what tools and attachments are needed for this.
What you need to know about cutting angles
Tooth geometry of band saws can be changed depending on the characteristics of the material to be sawed. This is expressed in the shape of the tooth and the distance between the individual elements of the cutting edge.
The profile of a band saw blade is determined by a marking that is applied by the manufacturer. It looks like this:
- WM. a versatile option designed for sawing soft and hard wood;
- AV. used for longitudinal cutting and sawing hard materials, such as frozen wood;
- NV. characterized by a narrow blade width, so it is ideal for shape cutting;
- NU. cutting edge with a wide tooth pitch, which provides high performance when cutting soft wood;
- PV. almost a full analogue of the previous blade, but has a flattened shape of the teeth;
- KV. profile is used for wide band saws designed for soft wood;
- PU. wide saw for sawing hardwood.
Tooth pitch is individually matched to the material. For example, only fine-toothed blades are used for cutting hard wood and metal to prevent damage to the cutting edge. Soft materials and thick-wall materials are processed with saw blades with big spacing between teeth, what allows to speed up the production process.
Bandsaw pitch types
As with any other tool, band saws are subject to wear and tear after every cutting cycle. It is a natural and unavoidable process. That’s why every band saw needs regular and expert service. setting and sharpening. Such maintenance allows not only to keep the cutting blade in working condition, but also significantly increases its service life.
Correct setting helps to increase blade life and significantly improves its functionality. The idea is this: the saw’s cutting teeth are offset in different directions to reduce the friction that occurs during cutting, and to minimize the risk of the blade being jammed by the workpiece. The setting of the band saw blade can be done in three ways, which depends on the type of material being worked.
- In the so called deburring set design the teeth are bent so that every third tooth is untouched. Such arrangement is used if cutting blade will be used for cutting of especially hard metals and alloys.
- The classic type of setting means that each cutter blade is set in turns.
- In corrugated setting, each cutting tooth is bent at a certain angle. It is clear that this type of wiring is the most complicated of all the others.
For band saw teeth bending special equipment is used, which allows to perform such technological operation quickly and with maximum accuracy. According to common standards the maximum degree of teeth setting shouldn’t exceed 0,7 mm, but usually it’s in the range of 0,3-0,6 mm. It is important not only to choose the type of resharpening, based on the characteristics of the material to be sawn, but also to do it correctly, bending the teeth only 1/3 or 2/3 of their height.
After setting, you can send the cutting blade to the band saw sharpening machine. Statistics show that band saws most often lose their functionality because they were not sharpened properly or on time. An indication that the band saw must be set and further sharpened on the machine is an increased roughness of the cutting surface. The need for such a procedure can also be determined by the appearance of the cutting teeth.
The key components of all sharpening machines are grinding wheels, the selection of which depends primarily on the hardness of the material used to make the cutting teeth. In order to sharpen hard materials, the appropriate wheels must be used. For example, for sharpening bimetal type blades choose sharpening tools consisting of borazon or diamond elements, and for sharpening saws made of tool steel, corundum wheels are quite suitable.
Tools for resharpening band saws are chosen according to their composition and design. The following types of wheels can be used in the machines for different blade designs and sizes:
Wood-Mizer band saw blade sharpening and set-up kit
According to the instructions, the following points must be observed when sharpening band saw blades on the machine.
- There must not be any burrs on the tooth surface when sharpening.
- Sharpening wheel must remove the same layer of metal along the whole tooth profile.
- To avoid overheating the teeth, it is imperative that a special coolant be used when sharpening them on the machine.
- The profile and height of the tooth to be sharpened must not be altered when sharpening.
- Always pay attention to the pressure exerted by the sharpening machine’s wheel on the tooth to be sharpened. If care is not taken, the pressure can be too great and the tooth can be burnt out.
Band saw sharpening with your own hands has some peculiarities. In such cases, as a rule, the back surface of the teeth is sharpened, although if you use the manufacturer’s instructions or watch a thematic video, you can also sharpen their front surface.
Design features of band saws
- Cutting (kerf) width of band saws is much less than that of their circular counterparts. When cutting cheap wood it is not so noticeable, but when cutting valuable and exotic types of wood it is critically important.
- The machine can cut blanks of any size. In this case, the band tool works quickly and creates a high quality cut.
- Very little waste (chips, sawdust) is generated by this type of saw.
Please note! To ensure that the machine always works steadily and with high quality, it should be maintained responsibly. Sharpening and distributing of band saws on wood should be carried out in a timely and competent manner.
Profile, teeth and sharpening angle
International Classification of Tooth Profiles.
Tooth geometries of band saws vary depending on the type and characteristics of the material to be cut. Wood tools can be carpentry and dividing tools. There is also a third type, designed for sawing beams, logs. All these subspecies have their own parameters and tooth shapes.
Angle of resharpening of band wood saws is chosen by the manufacturer based on several points. The main rule is that the harder the material, the smaller the rake angle should be. Below is a table with the basic parameters of the saws.
|Saw Features||Joinery fixtures (1 profile)||Divisional analogues||For sawing logs and cants (4 sections)|
|2 profile||3 profile|
|Thickness at the blade, in mm||0.6-0.9||0.9-1.2||0.9-1.2||1.4-2.2|
|Width at blade, in mm||10-60||50-175||50-175||230-350|
|Tooth pitch, in mm||6-12||30-50||30-50||50-80|
|Tooth height, in mm||2-6.5||9-13||7.5-15||16-24|
|Rounding radius at the trough, in mm||1.5-2.5||3-4||3-4||5-8|
|Rear angle, deg.||35||20||15||12|
|Grinding angle, in degrees.||50||45||45||53|
|Angle forward, in degrees.||5||25||30||25|
How to properly sharpen band saw
Immediately note that if you do not have experience and skills to perform such works, it is better to entrust the sharpening of saws to professionals. Disturbance of geometry of teeth of cutting edge, scale on metal or wrong setting noticeably reduce service life of band saw blade.
Deciding to sharpen a band saw with your own hands, it is not unreasonable to first become familiar with the key definitions, knowledge of which may be required in the process of work. So, in order to properly shape a cutting edge you’ll need to:
- setting. deflection of teeth from the plane of the main saw blade;
- Tooth height. distance between top point and base;
- pitch. the distance between the teeth, usually ranging from 19-25 mm.
- sharpening angle. depends on the purpose of the tool; for example, the recommended sharpening angle for carpenter saws is 35°, for circular saws. 18-22, for sawing beams. not more than 15°.
Angle of sharpening is defined by the manufacturer, therefore it is recommended to adhere to these parameters when dressing the saw by yourself.
Here is a detailed instruction that will help you properly sharpen a closed circular saw without resorting to the services of specialists.
Sharpening band saws in wood is the first step in restoring the cutting edge profile. tooth flank may change over time, so there is no point in resharpening the saw blade until the geometry is correct.
- Classic. Teeth are alternately bent to the right and left side;
- deburring. 1st and 2nd teeth are deflected to different sides, the third stays straight. This profile is created for sawing hard materials;
- Corrugated is the most complicated version, resembling a wave shape. Each tooth is given an individual shape, and this type of reaming is usually done only in a specialized reaming center.
It should be noted that when deburring, not the whole tooth is deburred, but about 2/3 of the upper part. The procedure is performed on a special band saw dressing machine. The cost of such a tool is quite high, so it is bought if several tools need to be sharpened. Its availability can be the basis of a sharpening business.
Of course, you may not get it right the first time, even on the adjustable machine, so at least the geometry of the profile should remain the same as before the start of the work.
This is the main stage of the straightening of the cutting edge, which can be done in two ways.
Full profile saw sharpening is performed with an CBN wheel mounted in a special sharpening machine.
It is a fully automated operation used by professionals. The wood band saw sharpener is controlled electronically and the sharpening wheel processes the complete band in one pass. The disadvantage of this method is that the CBN wheel is matched individually to the profile of the saw, so for dressing different tools the sharpening element must be in stock.
Tooth sharpening is performed manually or with the help of specialized equipment.
Please note! This is the method used for resharpening band saws by hand. Here you can use an ordinary emery wheel or file.
In the first case, you can restore the sharpness of the teeth in the shortest time, but the work requires certain skills. In the second. painstaking work: 4-5 movements on the edge of each tooth.
Diamond, CBN and corundum grinding wheels are used for automated sharpening. It is important to realize that this procedure only sharpens the teeth, the geometry created after resharpening must remain unchanged.
Angle of resharpening for band saws in wood
We would like to point out the usual mistakes that occur during the sharpening and unsharpening of the band saw blade.
Such cracks occur due to improperly installed guide rollers. As a result the back side of the saw keeps rubbing against the roller skirting during the work.
3 and 3a. Visually you can see that when sharpening, the sharpening wheel passes the incomplete tooth profile. Error in setting the angle of the sharpening head or in the profile of the sharpening stone if a non-Borazon CBN blade is used.
Alternatively, the cause could be a worn eccentric on the sharpening machine. Cracks appear where they were not ground.
4 and 4a. Zero angle of attack. the band is chattering heavily during cutting, which causes the saw head to vibrate. In this case, cracks appear on the saw body at the location indicated by the circle.
Caused by improper installation of the sharpening machine head. At a very low (4a) tooth height the band starts to “wobble” because the slot is not big enough to eject the sawdust, which in this case is very fine (dust).
Tooth not fully ground. The reason for this is the off-axis positioning of the sharpening head in relation to the clamping plate. The belt will blunt quickly.
Too much tooth dilution. The cutting edge of the tooth (tip) is not equidistant from the edge of the band slot, which dulls very quickly. Significant head jerking occurs during sawing.
The mouth of the band saw is set too low causing noticeable deflection of the band below the tooth notch. This band makes a wave in the kerf despite the correct readings of the riving tool.
Dariusz Kujawa Head of Customer Service Wood-Mizer, Poland
Band saws are more difficult to sharpen than other types of saws. This is caused not only by the design features of such a tool, but also by the need to carefully control the process and accuracy of angles, as such saws are used for artistic woodworking, as well as for working with valuable species. Band saws are also quite easy to damage during the sharpening process. There is a real danger of the tape becoming unusable if a number of rules for working with it are not followed. About how to properly sharpen band saws for work on wood, how to avoid mistakes in the sharpening process, will be described below.
To sharpen band saws, you need to buy sharpening wheels and a sharpening machine
Angle of resharpening of band saws table. Recommendations
Sharpening band saws for wood, instructions and safety rules for this operation. these are the main issues that every home handyman who has saws of such design in his household should know. The fact that they are used not only in production, but also in everyday life. For example, many people in the countryside use them for making boards or sawing logs into logs.
However, like any saw, band saws need to be periodically repaired. In this case, this maintenance consists in the implementation of such technological operations as sharpening and deburring. They are quite complicated technically, and if you have no experience with them, it makes sense to contact a specialized service center for sawing and cutting tools.
If you have experience with woodworking tools, you may be able to deburr and sharpen your saw yourself. The point of doing such work yourself is to save money, t. к. Saw sharpening is expensive enough.