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How to drill a disk from a circular saw video. How to drill hardened steel, methods How to drill a hole in a circular saw

Of course, you need to drill steel until it’s hot. And if you come across a hardened workpiece (especially a thick one), release it, drill holes with a regular drill and harden it again, if necessary. But this option is not always possible and justified; sometimes non-standard situations arise in which it is necessary to drill (perforate) steel that is already very hardened.

Well, for example, the blade of a knife broke, or you decided to make a knife from a piece of a saw. It’s a pity to throw away such valuable material; skilled people usually give such things a second life...

Yes, it’s not technologically advanced, but folk craftsmen have come up with many different ways to drill hardened steel, or how to make holes in it. To do this with less effort, you need to proceed from the capabilities and materials that you have, and also depending on what purposes. Maybe, instead of a hole, you will be satisfied with just a slot with a grinder, into which you can pass a screw and secure the part. To make the slot smaller, you need to make it on both sides, and use a trimming disc of the smallest diameter, i.e. almost erased.

Before drilling, you need to thoroughly examine the steel to see how hard (crumb) it is, and from there choose methods. If, after all, the steel bends at least a little and then breaks (this can be determined by the broken end or by running it with a file), then it can be drilled with an ordinary concrete drill with pobedit tips. True, the drill must be sharp. It is also very advisable to change (correct) the sharpening of the drill, the angle, like a metal drill, then the drilling process will go much faster.

But it is useless to sharpen a Victory drill on ordinary sandpaper; this should only be done with a diamond wheel, then it can be done easily and effortlessly. And if you don’t have a diamond wheel, just take a new concrete drill with pobedit tips.

When drilling hardened steel, you need to press the drill quite firmly and drill at high speeds (if the drill is dull or not sharpened like for metal), having previously lubricated the drilling site with w-40 spray or oil. It will be easier to make a hole if you drill first with a drill of a smaller diameter, and then with a larger one. The resistance area will be smaller, and therefore the drill will go into the material easier...

Thin steel, for example, for a knife, can be drilled with hardened rods or Pobedit rods, you need to sharpen them like a drill and several pieces at once (make a peak and sharpen 2 edges), and change them as they become dull. A couple of minutes and the hole is ready...

From my experience, I can say that it’s good to make holes in hardened steel with all-alloy Pobedit drills; I had a couple, 6 mm in diameter. Having sharpened it as if for metal, I dropped some oil, and everything goes like clockwork, at about 600-1000 rpm.

The next method is long, requires several hours, but reliable. A hole in a steel plate can be easily etched with acid: sulfuric, nitric, or chloric, 10-15% will do. We make a side of the desired diameter and shape from paraffin, drop acid there and wait. The hole turns out to be slightly larger than the diameter of the side, this must be taken into account. To speed up the process, the workpiece can be heated slightly, to about 45 degrees.

If you have a welding machine, this can also be used. The hole can simply be burned into the workpiece or locally “released” and then drilled. Grind the melted edges then and order.

Or, I managed to get out of the situation using the following method: marking the drilling site with some kind of drill, as long as it was visible, and then poked it around with an electrode, heating the metal until red hot at the drilling site - and then, without waiting for the metal to cool down, there I drill steel with a regular metal drill. I then clean the welding points all around, and everything is in order. And if you managed to drill a hole before the metal cooled down, immediately put it in water, it will also be hardened in this place...

I did the same thing if I needed to slightly widen the hole in the steel plate. The file didn’t take the hardened steel... Then I heated the metal by welding, at least to a cherry color, and - until it cooled down - I corrected it with a round file. Even if the steel was already almost gray in color, the file still took it.

There are, of course, special drills for such purposes, but they are not cheap, around $4 apiece. These are tubular diamond drills for high carbon steels.

A feather-shaped drill designed for drilling glass is also suitable, although not entirely ideal. The feather-shaped drill must be used carefully, do not press too hard, so as not to break it. The plates there are a bit thin, and the fragile one will win...

You can also make a hole in a steel plate using the burning method, at high speeds and a special carbide nozzle. For this we make a special “drill”. From a pobedite plate (you can use a tooth from a circular saw) we make a round piece and sharpen it to a cone. We insert it into an electric drill and burn a hole in the plate at high speeds. The entire operation takes only a few minutes.

If the steel is not very tiny, for example, like on a hacksaw or on a spatula, then you can easily punch a hole of the required diameter with a punch through a supply of the same or slightly larger diameter.

It will be much easier to drill stainless steel if you drop soldering acid into the drilling site.

And if you have access to an enterprise where there is an electrical erosion machine, then holes can be made on such a machine without problems, in a matter of minutes.

Well, here are all the methods for drilling hardened steel so far. If some more appear, I’ll add them. Since I wrote this article, I have already done this a few times, so come on in :) And if you have your own unique method for drilling hardened steel, write.

Sharpening circular saws

Material and properties of carbide teeth

In domestic saws, sintered tungsten-cobalt alloys of grades (6, 15, etc., the pattern means the percentage of cobalt) are used as the material for cutting inserts. At 6 the hardness is 88.5 HRA, at 15. 86 HRA. Foreign manufacturers use their own alloys. Hard alloys consist mainly of tungsten carbide cemented with cobalt. The characteristics of the alloy depend not only on its chemical composition, but also on the grain size of the carbide phase. The smaller the grain, the higher the hardness and strength of the alloy.

Carbide plates are attached to the disc using high-temperature soldering. Silver solders (PSr-40, PSr-45) are used as soldering material in the best case, and in the worst case. copper-zinc solders (L-63, MNMC-68-4-2).

Carbide tooth geometry

The following types of teeth are distinguished in the form.

Straight tooth. Typically used in fast rip saws where quality is not particularly important.

Oblique (oblique) tooth with left and right angle of inclination of the rear plane. Teeth with different angles alternate with each other, due to the fact that they are called alternating. This is the most common tooth shape. Depending on the size of the grinding angles, saws with alternating teeth are used for sawing a wide variety of materials (wood, chipboard, plastics). both in longitudinal and transverse directions. High Angle Saws posterior plane used as a trim when cutting plates with double-sided lamination. Their use allows you to avoid chipping along the edges of the cut. Increasing the bevel angle reduces cutting force and reduces the risk of chipping, but at the same time reduces the strength and durability of the tooth.

Teeth can be inclined not only to the rear, but also to the front plane.

Trapezoid tooth. A feature of these teeth is the relatively slow rate of dulling of the cutting edges compared to alternating teeth. They are usually used in combination with a straight tooth.

Moving with the latter and slightly rising above it, the trapezoidal tooth performs a through cut and a straight line, following it. clean. Saws with alternating straight and trapezoidal teeth are used for cutting double-sided laminated plates (chipboard, MDF, etc.) and also for sawing plastics.

Conical tooth. Saws with a conical tooth are auxiliary and are used to remove the bottom layer of the laminate, protecting it from chipping during the passage of the main saw.

In the vast majority of cases, the front side of the teeth is flat, but there are saws with a concave front surface. They are used for cross cutting finishing.

Teeth grinding angles

The grinding angles are determined using a saw. those. one for cutting the material and in which direction it is intended. Rip saws have a relatively large rake angle (15°.25°). In crosscut saws, the γ angle typically ranges from 5-10°. Universal saws designed for cross-cutting and longitudinal cutting have an average rake angle. usually 15°.

The grinding angle values are determined not only by the cutting direction, but also by the hardness of the saw material. The higher the hardness, the smaller the rake and back angles (less narrowing of the tooth).

The front angle can be not only positive, but also negative. Saws with this angle are used for cutting non-ferrous metals and plastics.

Basic principles of sharpening

Equipment and materials for sharpening saw blades

When using abrasive wheels (especially diamond wheels), it is advisable to keep them cool.

As the temperature increases, the microhardness of abrasive materials decreases. Increasing the temperature to 1000 °C reduces the microhardness by almost 2-2.5 times compared to microhardness at room temperature. Increasing the temperature to 1300 ° C leads to a decrease in the hardness of abrasive materials by almost 4-6 times.

Drilling a disc for a circular sawmill

drill disk for circular sawmill Disk saw 350x30 mm 24 teeth. woodworking CONSTRUCT WOOD BOSCH

How to drill hardened steel. Drilling a saw from a quick cutter

Little tricks. We drill hardened steel. There are many ways to drill through hardened steel. Someone's burning through

Using water for cooling may cause rust on machine parts and components. To eliminate corrosion, water and soap are added to the water, as well as some electrolytes (sodium carbonate, soda ash, trisodium phosphate, sodium nitrite, sodium silicate, etc.), which form protective films. In conventional grinding, soap and soda solutions are most often used and fine grinding is used. low concentrated emulsions.

However, when grinding saw blades at home with low grinding intensity, the wheel is often not used to cool the wheel. not wanting to waste time on this.

To increase the grinding ability of abrasive discs and reduce specific wear, you should select the largest grain size that provides the required surface finish of the pointed tooth.

To select the abrasive grain size according to the grinding stage, you can use the table in the article on grinding rods. For example, if diamond wheels are used, 160/125 or 125/100 grit wheels can be used for roughing. 63/50 or 50/40. Wheels with grit sizes ranging from 40/28 to 14/10 are used for removing teeth.

The peripheral speed of the wheel when sharpening carbide teeth should be about 10-18 m/s. This means that when using a 125mm diameter wheel, the engine speed should be around 1500-2700 rpm. More brittle alloys are sharpened at lower speeds in this range. When sharpening carbide tools, using harsh modes results in increased stress and cracks, and sometimes grinding of the cutting edges, while increasing wheel wear.

When using saw blade sharpening machines, changing the relative position of the saw and the grinding wheel can be done in different ways. movement of one saw (the motor with the circle is stationary), simultaneous movement of the saw and the motor, movement of only the motor with the circle (the saw blade is stationary).

A large number of grinding machines with various functions are produced. The most complex and expensive programmable complexes are capable of providing a fully automatic grinding mode, in which all operations are performed without the participation of a worker.

In the simplest and cheapest models, after installing and securing the saw in a position that provides the required sharpening angle, all further operations. turning the saw around its axis (turning on the tooth), feeding it for grinding (contact with the wheel) and controlling the thickness of the metal removed from the tooth. are made by hand. It is advisable to use such simple models at home when sharpening circular saws is occasional.

An example of the simplest machine for is the system photographed below. It consists of two main nodes. a motor with a wheel (1) and a support (2) on which a pointed saw is mounted. The rotating mechanism (3) serves to change the angle of the blade (when sharpening teeth with a beveled front plane). Using the screw (4), the saw moves along the axis of the abrasive wheel. This ensures that the specified front grinding angle value is set. The screw (5) is used to set the stopper in the desired position, preventing the wheel from excessively entering the interdental cavity.

Saw blade sharpening process

If there is no machine for sharpening saw blades

Precisely maintain the required sharpening angles while holding the weight of the saw in your hands. The task is impossible even for a person with a unique eye and enviable stiffness of hands. The most reasonable thing in this case. to create a simple sharpening device that allows you to fix the saw in a certain position relative to the circle.

The simplest of these tools is a grinding stand, the surface of which is at the same level as the axis of the grinding wheel. By placing the saw blade on it, you can ensure that the front and back planes of the tooth are perpendicular to the saw blade. And if the upper surface of the stand is made mobile. fixing one side hinged and the other. Relying on a couple of bolts that can be screwed in and out. then it can be installed at any angle, allowing you to sharpen an inclined tooth on the front and back planes.

True, in this case one of the main problems remains unresolved. Extracting the same front and back corners. This problem can be solved by fixing the center of the saw in relation to the abrasive wheel in the desired position. One way to implement this. Make a groove on the surface of the mandrel support on which the saw is mounted. By moving the frame with the wheel in the groove, it will be possible to maintain the required tooth cutting angle. But to sharpen circular saws of different diameters or sharpening angles, it must be possible to either move the motor or the support, and with it the groove. Another way to ensure the desired sharpening angle is simpler and install stops on the step that lock the disc in the desired position. At the end of the article there is a video demonstrating this adaptation.

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How to drill high-speed steel grade P6M5 or HSS according to the European designation? For example, we made a knife from a blade from a mechanical saw, and we need to drill holes in it with a diameter of 5-6 mm for pins to install and secure the handle pads.
The same operation may be needed to drill a hacksaw blade for metal from 1Х6ВФ steel, from which you can make some useful products. A piece of blade from a mechanical saw made of 9HF steel is suitable not only for making knives, but, for example, also non-standard keychains.

Necessary tools and samples

All of the considered and other grades of high-speed steels are drilled using spear-shaped (feather) drills for tiles, having different designs. For example, shanks are made round or hexagonal, which is not of fundamental importance for the main work - drilling.

They are freely sold in almost all construction stores or outlets selling all kinds of tools. What is very important, drills of this type and purpose are attractive because they are inexpensive.
Also, for drilling high-speed steels, you will need cutters of various shapes and designs. With their help, the accuracy, cleanliness, shape and required diameter of the drilled hole are ensured.

We have to drill the following samples:

a piece from a frame saw made of 9HF steel.
blade from a hacksaw for metal made of steel grade 1Х6ВФ.
Mechanical saw blade made of HSS steel.

The process of drilling high-speed steel samples

Let's start with a hacksaw blade for metal. As a tool, we will choose a used tile drill bit, which has already been sharpened more than once on a diamond wheel. That is, for a long time nothing remained of the factory sharpening, which would have undoubtedly given the best result.
We insert our tool into the chuck of an electric drill and start drilling without the use of lubrication or cooling. We select low speed as the operating mode. We notice that the process is slow, but with some patience, after some time a conical depression appears on the blade, a kind of countersink caused by the shape of our drill.

We drill until a tubercle appears on the other side.

After this, we turn the canvas over and continue the process, focusing on the tubercle.

Alternately drilling from one side to the other, we increase the diameter of the hole until we get the desired size.

The next sample is a blade from a frame saw. We select the drilling location at the base of the teeth, where the material has the greatest hardness.

The process also does not proceed very quickly, but steadily. This can be seen by the gradually increasing volume of chips around the drill.

We notice that the work goes faster if you slightly rock the tool from side to side. This helps remove chips from the cutting area.
We continue drilling on one side until the tip of the tool passes the entire thickness of the metal and forms a small tubercle on the other side of our sample.

Since the thickness of the metal is greater than that of a metal blade, we will have to replace the drill halfway through the process or resharpen the one we are using. After this, we turn the sample over and continue drilling.

After just a few turns of the drill, a through hole is formed. Continuing the process, we achieve the required diameter for the mating part.
Make the hole using a suitable cutter.

In our case, it is most convenient to use a conical-shaped tool. It is easier and faster to achieve the required hole size and give it a cylindrical shape.

After all, after using a feather drill with its large taper, the hole turns out to be different in diameter: closer to the surface of the sample it is larger, and in the center it is smaller.

Let's start drilling the blade from a mechanical saw.

To do this, we also choose a zone closer to the teeth, since in this place the metal is harder due to special hardening.

The process seems to be faster compared to the previous two samples. This can be seen from the intensity of chip formation and the production of a through hole without drilling from the reverse side.

One of the cutters will help to bring the hole to the desired diameter and give it a cylindrical shape, as in previous cases. Using linseed oil for drilling (it is used when working with stainless steel and contains oleic acid), it will be possible to increase productivity and sharpen the tool less often and improve the purity of processing.
Practice shows that the process of drilling high-speed steels will become more productive if you first use drills of a smaller diameter, and then a larger one.
Some craftsmen use screws or screws made in Germany and used for concrete work as tools for drilling high-speed steels. Their distinctive feature is that on the head there is the letter “H” (Hardened - hardened).