The sharpening angle of band saws in winter. Rules for sharpening band saws at home. Sharpening methods and equipment for it

We would like to tell you about typical mistakes arising during the process of sharpening and laying the tape.

1. Such cracks occur due to improper installation of guide rollers. As a result, the back of the saw constantly rubs against the side of the roller during operation.


2. In this case, the tape quickly becomes dull. The cause of this type of error is too much pressure on the grinding wheel during the sharpening process.

3 and 3a. It is visually noticeable that when sharpening the grinding wheel passes through an incomplete tooth profile. Error in setting the head angle sharpening machine or in the sharpening stone profile if a non-borazon CBN disc is used.

In addition, the reason may lie in the development of the eccentric of the sharpening machine. Cracks appeared in the place that was not machined.

4 and 4a. Zero angle of attack - the belt rattles a lot during operation, which leads to vibration of the sawing head. In this case, cracks appear on the body of the saw in the place indicated by the circle.

The cause is incorrect installation of the sharpening machine head. With a very small (4a) tooth height, the tape begins to “wave” due to the fact that the sinus is not large enough to throw out sawdust, which in this case is very small (dust).

5. The tooth is not sharpened completely. The reason for this is the off-axis installation of the sharpening machine head in relation to the clamp. The tape will quickly become dull.

6. Too much tooth set. The cutting edge of the tooth (top) is not equidistant from the edge of the groove of the tape, which becomes dull very quickly. There are significant jerks of the head during cutting.

So I'll start with general description band saw.

A band saw has the appearance of a blade having a serrated edge, connected into a continuous band. Simply put, this tool is nothing more than closed belt with teeth.

And to make sure that the band saw is a very significant cutting tool, I propose to consider its main advantages.

Advantages of a band saw

First of all, the most significant plus is the cutting width of the tool. Indeed, it is difficult not to notice that it is significantly smaller than that of disk tools. And if for sawing budget wood this moment is a mere trifle, then for cutting valuable types of wood and elite material it is better to use, for obvious reasons, band saws.

And then, in addition to this, a band saw can cut any workpiece. In addition, the tool has a decent operating speed and high quality cut surface.

But, of course, to experience all these advantages, you need to take a responsible approach to sharpening and setting the band saw.

Material for making band saws

The band saw for wood is made from tool steel with a hardness of 45 HRC, and for metal the steel used is V2F, 9HF, C75, Uddeholm UHB 15, etc., for carbon steels the cutting tool is based on tool steel, and the teeth for which they are used are hardened high frequency currents.

I would like to note that for cutting metal you can also use a bimetallic saw, which after hardening has a hardness of 65-69 HRC.

Having understood a little about the materials from which band saws are made, let’s move on to the teeth of the cutting tool and their sharpening.

Teeth and sharpening angles

Band saws have different tooth geometries due to various types and properties of the processed material.

If we consider wood, then the teeth are divided into:

• - carpentry;
• - dividing;
• - for sawing logs.

As for sharpening angles, the manufacturer determines this parameter. Basically, it is accepted that the harder the material, the smaller the rake angle.

For metal band saws, the teeth are usually shaped either standard or with a positive rake angle. Let me clarify this point a little: the standard tooth shape is used for sawing thin-walled material, and the shape with a positive rake angle, as you might guess, is used for cutting thick-walled material.

I suggest looking at a small picture that can explain what tooth profiles can be used.exist and where they, these same profiles, are applicable.

In addition, the pitch of the teeth is important. So, for example, for a thin-walled material you should use a tool with a small number of teeth, and for thick-walled materials, vice versa, with a large number teeth per inch.

Now let's take a look at the picture, in which we can clearly see how saws with variable tooth pitch differ from saws with a constant tooth pitch.

Often, saws are made with variable pitch in order to eliminate the resonance effect.

Band saw routing

The purpose of the setting is to bend the teeth to the sides to prevent compression of the tool blade and reduce friction.

There are several types of wiring:

• - using the classic setting, we get teeth that bend to the right and left alternately;
• - with the help of a cleaning pattern, every 3rd tooth retains its original position;
• - with the help of a wavy setting, each tooth is assigned its own bend value (thereby creating a wave).

It is important to know that during divorce, part of the tooth is bent (one third or two thirds from the top), but not the entire tooth.

Band saw sharpening

To prevent the tool from breaking during operation, it is necessary to follow the sharpening rules.

The hardness of the teeth determines the wheel that will be used for sharpening. Thus, tool steel is processed with a corundum wheel, and a bimetallic saw with a diamond or bronze sample. The tool parameters determine the shape of the grinding wheel.

Typically, the following forms are used:

• - profile;
• - cup;
• - flat;
• - disc-shaped.

Before proceeding directly to sharpening work, it is necessary to let the saw hang for 10-12 hours in an inverted state.

There are two main ways to sharpen a band saw.

1 way

Referred to as full-profile sharpening. It is produced on an automatic machine, which immediately means that the sharpening will be of high quality. The principle of sharpening is based on passing the entire interdental cavity with the corresponding surfaces of adjacent teeth in one movement with a CBN wheel, which is directly selected according to the shape. It follows from this that we will not get angular shapes at the base of the teeth. This is simply out of the question.

Wheels are often used, the abrasive of which can be electrocorundum, CBN or diamond sputtering.

Perhaps the only significant disadvantage of this method is that different saws require different circles.

Method 2

Characterized by sharpening of the tooth edges. It can be done using a machine, then the circle is selected again. Manual processing is carried out by an engraver or on a conventional machine in compliance with safety precautions, or using a needle file (its essence is to make several movements along the front or back surface teeth)

To sharpen a band saw with your own hands, you need to:

• - eliminate strong pressure on the circle;
• - ensure uniform metal removal along the tooth profile;
• - ensure the preservation of the height, as well as the profile of the tooth;
• - control the absence of burrs;
• - use coolant.

If there are nicks on the surface of the tooth, the saw will quickly become dull. Therefore it is important to have smooth surface teeth It is also necessary that the radius at the base of the tooth is maintained. This is necessary to prevent cracks and tearing of the fabric.

The saw should be sharpened as soon as there is noticeable force to move it in the wood. Most woodworkers are happy to sharpen their tools, but may call a professional if the teeth need to be set. Grinding should be done after 4-5 sharpenings or if the saw “moves away” from the intended direction due to incorrect setting. Electrically hardened teeth cannot be sharpened by hand, and dull replacement blades for fine work are simply thrown away.

Files for sharpening saws

The cutting edge of each tooth is processed with a triangular file. The edge of the file should be approximately twice as high as the tooth.

Saw sharpening guide

This device ensures the uniformity of the angle and depth of sharpening of tenoning and other hand saws.

Mandrel for setting teeth

The setting mandrel will deflect the tip of the tooth to a strictly defined angle. The approach of the handles pushes the plunger, which presses the tooth against the stop at an angle. The stop has a graduation showing the size of the tooth to which a particular set angle corresponds. It is recommended to have a fine-toothed saw cut by a specialist.

Saw sharpening clamp

When sharpening, the saw must be securely fastened, otherwise it will vibrate noisily and knock the file out of the recess between the teeth. Make an improvised clamp from two bars cut to the length of the canvas, with a shape that “goes around” the handle. Clamp the saw between the blocks in a workbench vice. If necessary, use a clamp at one end.

Machining tooth tips

Thorough filing of the tops of the teeth is absolutely necessary to level them in height if the saw has been damaged or improperly sharpened.
This operation, in a simplified form, before sharpening, forms a small shiny spot on the tip of each tooth, which will be an invaluable aid for uniform sharpening. Make the jig by placing a personal file into a slightly converging groove in a block of hardwood and secure it with a wedge. Move this clamping block along the side of the blade so that the file moves along the tops of the teeth. Two to three light strokes should be enough to prepare for sharpening the saw teeth in good condition. If your saw requires extensive machining to ensure all the teeth have a shiny speck, contact a professional who will shape them before setting and sharpening.

Saw teeth set

If the saw begins to bend or get stuck in the cut, re-set the teeth. Prepare the mandrel for work: loosen the locking screw and turn the fence, aligning the tooth size indicated on it (corresponding to your saw) with the mark on the fixture. Tighten the locking screw and set each tooth that should be tilted away from you. Turn the saw over and repeat the operation with the other teeth. Check to see if you have missed a tooth by holding the saw at eye level with the teeth facing away from you.

Sharpening with a file

Place the saw in a vice between two blocks so that its toothed edge protrudes slightly from the top and the handle is to your right.
Holding the tip of the file with your free hand, start at the end of the blade, resting the file on the first tooth angled away from you, opposite the leading edge of the adjacent tooth angled toward you.
For rip saw Place the file in the corner between the teeth at right angles to the blade and strictly horizontally. Make 2-3 strokes with the file (applying pressure only on the first stroke) until half of the shiny spot on the top of the tooth disappears. Moving towards the handle, sharpen every second tooth. Turn the saw over and repeat from the end to the handle, filing the remaining grooves until the shiny spots disappear and sharp tips appear.
Sharpen the crosscut saw in the same way, but with the file tip facing the handle at approximately 65° relative to the blade.
Parallel 65° lines on the clamping bars will help keep the file in the correct direction.

From all that has been said above, it is difficult not to notice that the apparent simplicity of sharpening a saw is just “apparent”. It is necessary to strictly follow the rules of wiring, sharpening the tool, the rules of its use, in the end. And then the band saw will serve you for a long time, faithfully and practically.

The band saw is an integral part of any band saw machine. Under constant heavy load, the tool should definitely be sharpened. This can be done in specialized centers, spending a significant percentage of time and money. But you can do it yourself, guided by a number of simple rules.

Types of band saws

Visually, band saws practically do not differ from each other. The only difference that only a master can notice is the type of teeth, which is selected in accordance with the type of material being cut. The variety of saws for wood can be divided into main categories:

• carpentry type;
• dividing;
• sawing

Based on the work being carried out, the appropriate tool with suitable type teeth

Band saws can have a variety of tooth geometries: it is influenced by the type and properties of the raw materials being cut. The basic rule of operation: the harder and denser the material being cut with a band saw, the smaller the front angle of the teeth of the product, as well as their pitch, should be.

Figure 1. Scheme of setting the teeth of a transverse and longitudinal saw.

This way you can improve the quality of the product and extend its service life.

To cut thin-walled surfaces, you can use a saw with a standard or fine tooth pitch, adapted for working with these materials. If a saw with a large pitch of teeth is used for these purposes, the risk of its failure will increase significantly. It would be more appropriate to use such a tool for thick-walled surfaces made of metal or wood, securely fastened before starting work.

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How to sharpen a saw correctly?

In order to properly sharpen a band saw, it is not necessary to seek the help of a professional. It is enough just to arm yourself with the basic rules for implementing this procedure, prepare necessary tools and remember the basic safety precautions:

1. Band saws are sharpened using a special wheel, selected based on the hardness of the tool teeth. Depending on the technical features saw, the shape of the grinding wheel is also selected (flat, profile, plate-shaped or cup-shaped).
2. Before sharpening, the grinding wheel should be checked for its ability to evenly remove metal over the entire surface of the teeth.
3. Sharpening should be carried out without jerking or sudden movements in order to maintain the original appearance and height of the teeth.
4. The mechanism of the grinding wheel must certainly contain a coolant, which can eliminate the possibility of overheating of the mechanism, and also ensure more accurate sharpening of band saws.
5. After processing the surface of the saw is completed, it is necessary to check whether there are any clinging elements left on it. If such moments are found, they can be removed using a grinding machine or the same grinding wheel, if you bring the band saw to it at a certain angle.

The work carried out must be carried out exclusively in a respirator or mask!

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Types of saw sharpening

Band saw sharpening is often carried out in two main directions: full-profile - using professional machines - and sharpening the edges of the teeth themselves.

The first method is rightfully considered the most accurate, because all actions are performed by an automated mechanism. In order to sharpen a saw perfectly, you only need to choose the right CBN wheel, which is the basis of the sharpening machine; it will do the rest on its own. The only drawback of this procedure is that it high price, because at your disposal you need to have not only the machine itself, but also a set of CBN wheels suitable for all variants of band saws.

The second method, focusing only on the saw teeth, involves both manual processing and sharpening on a professional tool. The first option only requires the presence of an engraver and the skill of the one who sharpens. His movements must be fast and precise to avoid damage to the metal. When performing such manipulations for the first time, it is recommended to first hone your skills on a simple sheet of metal. Otherwise, you can simply ruin the instrument. The best option is to walk along the back and front edges of band saws on wood, but most craftsmen neglect this condition. For the tool to function correctly, it is enough to sharpen only the rear edges, and this will be much easier and more convenient to implement. You can sharpen the front edges without difficulty if we're talking about about working on the machine. Here, as in the case of full-profile sharpening, you just need to choose the right shape and size of the grinding wheel.

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Band saw routing

Ordinary sharpening is sometimes not enough to get a good band saw. Not the least role in this issue is played by the degree of bending of the teeth of the product - the setting. The essence of the procedure is to reduce the friction force and ensure free movement of the sawn surface between the teeth.

The most common layout - standard - assumes that all saw links are alternately bent in different directions by no more than 0.4 mm. You can do it at home, making sure that the angle of deflection of the teeth is approximately the same.

The second type of alignment - protective, is almost never done independently at home, since the essence of the procedure is to bend two teeth at different angles, leaving the third intact. The wavy layout is considered similar in complexity, and fully lives up to its name. The links gently bend in one direction, forming a kind of wave between themselves, tightly adjacent to each other.

Carrying out wiring on our own, the master must also take into account the fact that different kinds saws require a radically different approach. The tools usually come with instructions given by their manufacturer, indicating the density of the metal and the recommended deflection angle. It is often limited to the range of 30-60%, but other values ​​are possible for some products.

This wiring can be done using a special wiring device that looks like shown in Fig. 1.

You can work in it according to the scheme presented above, having previously set the required mode on the indicator and moving the teeth in different directions using a hand lever.

The return action to the initial state of the device allows you to automatically move to the next pair of teeth in accordance with the set mode. Thus, with little effort, even the simplest and most inexpensive saw can be turned into the necessary one. this moment tool.

The service life of a wood band saw directly depends on the quality of its sharpening. It can be done either independently or using the services of specialized companies. In the first case, it is necessary to familiarize yourself in detail with the technology and a number of features.

Band saw design

The band saw belongs to the category of cutting tools and is an integral part specialized equipment wood processing. It is a closed belt with teeth on the outer edge.

For production, special grades of steel are used - 9ХФ, Б2Ф or С75. During the production process, teeth are treated with high-frequency currents. This increases their hardness. It is this fact that affects the spread of cutting edges and maintainability. Often several types of steel are used in manufacturing. The main tape is made of spring, and cutting part- made of steel with high content tungsten or cobalt.

Features of using band saws for wood:

• wood requirements. The harder it is, the faster the blade will become dull;
• installation conditions. The tension indicator must be observed. If it is less than required, sagging will occur. With strong tension, the likelihood of fabric breakage will increase;
• periodic sharpening. This will require a special machine.

Completing the last point will increase the service life of the strip structure. However, sharpening it yourself is problematic - you need to choose the right layout and maintain the angle of the blades.

When buying a used saw, you need to pay attention to the presence of repair welds on the blade. They indicate frequent tool breakdowns.

Cutting part shapes and sharpening angle

At the first stage, the type of band saw is determined. The main indicator is the shape of the teeth. Depending on this parameter, they are divided into dividing, carpentry or intended for sawing logs. The initial geometry and routing angle are determined by the manufacturer. It is recommended to find out this data at the stage of purchasing components. They are needed to determine the machine parameters.

For hardwoods, the rake angle should be kept to a minimum. This ensures optimal contact between the processing material and the metal. If you plan to process soft varieties, you can use models with great value front corner.

The determining parameters for self-updating the cutting edge are:

• tooth pitch. This is the distance between the cutting elements of the structure. Common values ​​are 19, 22 and 25 mm;
• tooth height. The size from its base to its top;
• corner. The main value that you need to know to form the cutting plane. For carpentry models it is 35°. In dividing saws, the angle is from 18° to 22°. In structures for processing timber – 10°-15°;
• divorce. Determines tooth deviation from common plane canvases.

After performing work on the machine, ideally these characteristics should remain unchanged. For each model, the manufacturer determines the maximum deviation value. If during operation this is achieved, it is necessary to purchase a new model.

In order to eliminate resonance, some types of cutting tools use a variable pitch of the teeth. This does not affect manual sharpening, but requires careful setting of parameters during automated sharpening.

Band saw routing

Before forming the cutting edge, the teeth must be set correctly. During the entire period of operation, due to constant loads, their location may change. Therefore, the geometry is adjusted first, and then sharpening occurs.

The setting is a bend of the teeth relative to the plane of the main blade. This procedure is performed only on a special machine. In case of large discrepancies along the entire length of the belt, premature damage or breakage of the web may occur. Therefore, before this you should decide on the type of wiring.

The angle of inclination must correspond to the original one. The type of wiring is also taken into account, which can be as follows:

• classical. Alternate bending of the teeth relative to the blade to the right and left sides;
• cleaning The first and second teeth deviate to the right and left, but the third remains unchanged. This technique is used for saws that are intended for processing hard rocks;
• wavy. The setting angle for each tooth is individual. As a result, they form a cutting edge that resembles a wave. The most complex type of wiring.

During bending, not the entire tooth is subject to deformation, but only part of it. Often the deviation occurs by 2/3 of the total height.

The average divorce value is limited to values ​​from 0.3 to 0.7 mm. This applies to standard wood band saw models.

It is important right choice type of grinding wheel. It must match the grade of steel from which the band saw is made. Corundum wheels are used for structures made of tool steel. If you want to improve the cutting properties of bimetallic models, you should use CBN or diamond wheels.

Depending on technical capabilities, it is possible to perform full-profile processing or each cutting part separately. In the first case, you will need a CBN circle, the end of which has the same shape as that of the saw. For the second option, each tooth is processed.

You will first need a machine. It must have the functions of regulating the speed of rotation of the disk and changing its location relative to the tool. After securing the blade in a special frame, you should perform the following steps according to the following instructions.

1. The emery is directed downwards. At this time, the front face with the cutting edge is processed.
2. Forming a cut in the depression. This is done without leaving the canvas. This stage allows you to remove microcracks and irregularities. An important point is a decrease in surface tension, which is the main cause of fabric deformation.
3. The circle moves up. The back of the tooth and its cutting edge are ground.

All other teeth are updated using the same method. It is important that the values ​​of the entry and exit angles are the same everywhere. Otherwise, if the geometry differs in one of the parts, performance will deteriorate.

With prolonged contact of the circle with the metal, the temperature on the surface of the latter can rise sharply. To eliminate this effect, special coolants are used, coming directly from the machine. The feed is carried out continuously to avoid the formation of a glow zone. In this part, the mechanical strength will be deteriorated.

To avoid the appearance of nicks, before processing wood, you need to check for the presence of metal components in it. Also Special attention is given to fixing and uniform feeding of the workpiece for sawing.

All photos from the article

Band saws designed for cutting various materials, including wood various levels hardness Their working part is a closed steel belt with teeth.

The cost of sharpening band saws in special workshops is relatively low. But often the speed and quality of order execution are not very satisfying. Based on this, the work can be done on your own.

Design features of band saws

1. Belt devices are made from alloyed tool steel, which has a hardness of 40 to 46 HRC.

1. The width of the cut (kerf) of band tools is much smaller than that of disk analogues. When cutting cheap wood, this point is not so noticeable, but when cutting valuable wood, it is critically important.
2. The machine can cut workpieces of any size. At the same time, the band tool works quickly and creates a high-quality cut.
3. There is very little waste (shavings, sawdust) when using this type of saw..

Note!
In order for the machine to always work stably and efficiently, its maintenance should be approached with the utmost responsibility.
Sharpening and setting of band saws for wood must be carried out in a timely and competent manner.

Profile, teeth and sharpening angle

Tape devices have different tooth geometries, which depend on the type and characteristics of the materials being cut. Wood tools can be carpentry or dividing. There is a third type, designed for sawing timber and logs. All these subspecies have their own parameters and shape of the teeth.

The sharpening angle of wood band saws is selected by the manufacturing company based on several points. The main one is that the harder the material, the smaller the rake angle should be. Below is a table with the main parameters of the saws.

Characteristics	Carpentry tools (1 profile)	Dividing analogues			For cutting logs and beams (4 profile)
		2 profile		3 profile
Thickness of the canvas, mm	0.6-0.9	0.9-1.2	0.9-1.2		1.4-2.2
Width of the canvas, mm	10-60	50-175	50-175		230-350
Teeth pitch, mm	6-12	30-50	30-50		50-80
Height of teeth, mm	2-6.5	9-13	7.5-15		16-24
Rounding radius at the cavity, in mm	1.5-2.5	3-4	3-4		5-8
Rear angle, in degrees.	35	20	15		12
Sharpening angle, in degrees.	50	45	45		53
Front angle, in degrees.	5	25	30		25

Preparing the device for work

With constant use of the tool, a decrease in the quality of the cutting edge is inevitable. It becomes dull, and the width of the teeth is reduced. Based on this, sharpening a wood saw and setting it up are necessary components Maintenance band saw machine.

It should be noted that the setting of the teeth should be carried out before sharpening them, and not vice versa.

Tool layout

Setting is the process of bending the teeth to the sides. This operation is necessary to ensure that the saw blade does not clamp in the workpiece, and also to reduce friction during operation.

There are 3 main types of breeding.

1. At classical method the teeth bend left and right in strict order.
2. With the stripping method, every third of the teeth remains in its original position. It is optimal for devices designed for cutting particularly hard wood.
3. With a wavy setting, each tooth is given its own separate bend value. In this case, the profile of the canvas takes on the appearance of a wave. This method most difficult.

Note!
When setting, you should not bend the entire clove, but only a third or two-thirds of it from the top.
Manufacturing companies advise performing the operation so that the bending range is within 0.3-0.7 millimeters.
The work is carried out using a specialized spreading tool.