Features of sharpening band saws

A well-sharpened band saw for metal and wood is the key to productivity and long tool life. As a rule, such services are provided by special organizations, but if you know the sequence of actions and features of the process, you can sharpen a blunt saw on your own.

The key component of every band saw is the band saw (blade). Bandsaws are widely used when working with wood, metal, rubber, plastic and a variety of flexible materials.

There are three types of these products.

1. Manual tape devices - these machines can be called household, they are most often used at home.
2. Desktop modifications - these units are more often purchased for small industrial facilities, woodworking companies, workshops.
3. Stationary units - such installations are related to the category of professional ones, they are used in large industries, factories, factories, large workshops, and so on.

The basis for the separation of this type of saws is the material of manufacture and the elements being processed. In accordance with such aspects, the following types of canvases can be distinguished.

• Saws for wood. The key materials for their manufacture are carbon and alloy steel grades, their hardness reaches 40–45 HRC. All teeth are subject to high-frequency current hardening without fail. It should be noted that such a material of canvases can be used to cut thin non-ferrous metals or carbon steels.

• Canvases for metal. Such tools are made of high-speed or spring steel (cobalt and tungsten are added to the structure) steel. These saws already have strengths up to 69 HRC. To obtain high hardness and ample opportunities, stellite or other types of strong alloys can be welded onto the teeth.

To service the canvases, it is not enough to sharpen the teeth, it is also necessary to dilute them. These two procedures are performed in succession: they start with setting the teeth, and finish them with sharpening. It is required to strictly adhere to such a chronology of works. Breeding is carried out in order to reduce the friction of the saw in the process of cutting a particular material (wood, metal, plastic, etc.). There are several methods of dilution, which depend on what elements need to be obtained subsequently, processing and the strength of the starting workpiece.

As the tool is used, there is a decrease in the properties of its cutting edge. Therefore, the breeding and competent sharpening of tape blades is a technical part of the working cycle.

Breeding is the process of bending the teeth to the sides to prevent the tool blade from jamming in the material being processed and to reduce friction. There are 3 typical breeding methods:

• classic - the teeth are retracted to the right and left sides strictly in turn;
• stripping - every third tooth remains in its original position. Especially important for devices intended for cutting, as a rule, strong alloys and materials;
• wavy - every tooth has its own value of the bend size, therefore, a wave is formed from them. This is the most difficult breeding.

The parameters of the wiring size recommended by the manufacturers are within the range of 0.3-0.7 millimeters. The procedure is performed using specialized adjustable equipment.

According to statistics, more than 80% of cases of breaks in the device occur due to failure to perform sharpening techniques. The need for sharpening is revealed visually - by the appearance of the teeth themselves or the state of the cut (increased unevenness of the plane).

Stones for sharpening tape blades are selected based on the stiffness of the teeth. For sharpening products made of carbon and alloy steel, corundum stones are used. Bimetal blades require borazon (CBN) or diamond discs. The configuration of the blade grinding wheel must be determined based on the characteristics of the tool. It can be dish-shaped, flat, cup, profile.

Before starting work, it is advisable to let the canvas hang in the unscrewed position for 10-12 hours.

Conditions for sharpening canvases with your own hands:

• ensuring the systematic removal of metal according to the shape of the section of the tooth;
• avoidance of excessive pressure on the disc (this can cause annealing);
• ensuring the integrity of the height and shape of the section of the tooth;
• the indispensable presence of liquid for cooling;
• control of the absence of scoring.

By and large, regardless of the abundance of rules and conditions, these devices are quite undemanding in terms of sharpening. You can deal with them both by means of a specialized sharpener for tape blades, and by hand. In addition, circles of various configurations and substances can be used for processing.

Before sharpening the tape, it is advisable to familiarize yourself with the key methods for performing this procedure.

This method is considered especially high quality and is performed on automatic equipment. Elborovy (Borazon) disc, precisely matched to the configuration, processes the entire interdental cavity together with the corresponding planes of adjacent teeth with a single pass. In this case, obtaining an uneven configuration at the base of the teeth is excluded. One drawback of such a sharpening is to constantly have a specific number of spheres at hand for canvases for different purposes.

It can be performed on specialized equipment or manually.

If special equipment is selected, then it is necessary to competently select a circle - as a rule, these are flat samples. By and large, it is advisable to turn to professional sharpening equipment only in those situations when the scale of work is quite large. It is preferable to carry out irregular "household" work by hand - by means of an engraver or on an ordinary machine. During work, for your own safety, it is imperative to use a mask or goggles.

If everything is clear with the sharpening of canvases under normal conditions, then sharpening in the cold season must be said separately. There is a difference in sharpening tape blades in the summer and winter cold. It consists in changing the degree of sharpening. The angle that is valid for canvases in winter should be 90 degrees, unlike in summer, when the sharpening angle is 120 degrees.

Recommendations from experts.

• When sharpening the blade with a machine, before starting the process, you need to make sure that the sharpening wheel is positioned accurately in relation to the tool.

• It is extremely important to remove such a volume of metal from the recesses so that all microcracks are reliably eliminated.
• If the blade has been functioning without normal maintenance for a longer time than allowed by the manufacturer, the volume of metal removed in one pass must be increased.
• Always use a new blade as a reference to test the effects of sharpening.

• The configuration of the blade tooth is an indicator that has been worked out and adjusted over the years. Therefore, it is a huge mistake to rely on the tool to cut “without a knot, without a hitch,” no matter what you do with the teeth.
• If operating standards are followed, the belt will work conscientiously until the width is reduced to a value equal to 65% of the initial parameters. The width decreases, of course, during sharpening.

• There is absolutely wrong advice that there is no particular need to remove scuff marks after sharpening. If you take it into account, then the occurrence of microcracks in the saw is ensured.
• At the end of the work, the tape blade must be cleaned of shavings and resin without putting it in a long box, and carefully inspected before sharpening. Otherwise, the risk of contamination of the grinding discs is very high. And this will certainly lead to a poor-quality sharpening process.

Accuracy 1. Burnt grooves in the blade teeth. The root cause of this phenomenon is hidden in the excessive efforts of the grindstone. The expected result is an early dullness of the canvas.

Accuracy 2. Incorrect tilt and imperfect tooth groove configuration.

Several circumstances can lead to a similar result:

• demolition of the copier of the sharpening device;
• error in adjusting the degree of inclination of the machine head;
• the dissimilarity of the grindstone profile.

Now you have information on how to sharpen the blades correctly, as well as what tools and equipment you may need for this.

You will learn about the features of band saw sharpening from the video below.