How to cut a hole in metal. Finishing the job

How to cut steel with a self-tapping screwdriver

Cutting holes in metal is simple, but there are cases when the usual tool is not able to provide the desired result. Or, for example, when it is cutting in hard-to-reach or inconvenient places. Let’s imagine that we need to cut a circular hole with a diameter of 100 mm in the thick-walled channel of 200 mm. It is almost impossible to do this evenly with a drill and an angle grinder. However, one uncomplicated device will help you do this with a self-tapping screw. In this article, we’ll tell you how to make an uncomplicated device for cutting holes with a self-tapping screwdriver as a cutter.

  • Drill;
  • Metal angle 50×50. 0.5m;
  • bolt;
  • nut. 2 pcs;
  • PTFE washer;
  • A washer made of nylon;
  • bearing (small);
  • hexagon for 12;
  • Self-tapping screws.

Quality drills on AlieXpress at a discount.

Marking the Metal

Before you cut a circle in the metal, you need to make a marking. You will need a mallet, punch, compass and marker.

  • Place the workpiece on a flat surface.
  • Mark the center of the hole with a punch and mallet.
  • Use a compass to draw a circle on the metal of the desired diameter.
  • Draw the contour with a marker.

Note! cutting trimmer line should be on the outside of the circle. It is necessary in order to get a part with the required diameter.

The peculiarity of deep holes

To drill a deep hole in the metal, it is best to use a lathe. During this process, it is mandatory to produce cooling. The chips must be forced out of the hole. Remove the tool from the workpiece at regular intervals to remove the chips.

Do not press the bit more than 2/3 of its length into the workpiece without special tools. Water must be used to cool the tool during operation. If work is performed in several passes, do not change the angle.


It has a small diameter, so it touches the metal with a smaller area when cutting. Use it to make a small depression around the edge of the hole. It is enough to deepen literally 1/3 of the steel thickness. As the wiped cutting disc has a small diameter, the mortise turns out flat, without the formation of notches outside the circle.

Having scratched the contour of the hole, a new cutting disc is installed on the angle grinder. Already with it, a square through hole is cut in the center of the circle. It should not reach the borders of the outlined circle by a few centimeters, it can be more.

Now you need to remove the rest of the metal between the contour of the round hole and the border of the square cut in it. To do this, use the angle grinder to cut the excess steel into 1-1,5 cm wide sectors. If the metal is thick, then making the cuts is better to observe a small step.

If the cut-off wheel had a small diameter, and the metal is split into narrow segments when breaking, the resulting hole will have a shape of a nearly perfect circle. It does not even need to be sanded. The same method can be used when necessary to make a hole in the tiles. Only in this case, the segments will be broken by the pliers immediately, without bending back and forth.

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We’ll need

Apply the varnish on the desired area. The varnish needs to be applied thickly on both sides. Do not forget to carefully blot the ends. Let the workpiece for 10-15 minutes to dry the varnish.

On the dry surface with a marker on both sides of the workpiece mark the place for the hole. The place I choose arbitrarily, now we need to show how this way you can make a hole. For example, you want to put a normal factory rivet. The diameter of the hole should be slightly smaller than the size of the rivet.

I pour water into a bowl and add 3 tablespoons of salt. The height of the water in the container should be 10 mm less than the height of the section of the workpiece covered with varnish.

I take a device made from the charger of the hair clipper and two nails. The nails will act as electrodes. I connected them to one terminal. The other contact is simply a stripped bare wire. I use a 12-volt charger, but a regular cell phone charger will do the trick.

The stripped wire should be the plus, the electrodes should be the minus. The plus wire with the clothespin attached to our workpiece. Then dip the nails in the water.

You can make slots in the reservoir to fix the position of the nails. Plugging the charger into an outlet. After turning on the water around the nail electrodes begins to bubble, and the cleared mark under the hole becomes black.

Note: to check the polarity of the wires it is necessary to connect the charger. If the water starts bubbling around the nails, then it is minus and you have connected correctly. The appearance of bubbles in the water around the workpiece tells you that the minus is connected to it and the wires need to be changed. Always keep the minus connected to the electrode, and the plus connected to the workpiece to be etched!We leave the container for one hour, after 30 minutes after the beginning of the process it is necessary to change the water. Disconnecting the charger and removing the workpiece.

A through hole is formed in the intended location. To make the hole larger in diameter, the process can be continued. Or file the rough edges with an emery board. This is how to etch high-speed steel using the most common objects to make the desired hole in the workpiece.

Make a hole in the glass without a drill

How to make a hole without a drill in the glass, so it does not crack. You will need molten lead for this.

  • Load the lead weights into the metal dish.
  • Light a torch and melt them.
  • Wipe the glass surface with alcohol to remove grease and other contaminants. Otherwise the glass may crack.
  • Sprinkle a heap of fine, wet sand on the cleaned area.
  • Use a stick to make a semblance of a well to form a vessel.
  • Pour molten lead into this vessel. Thanks to the wet sand the temperature inside the well will hold for a long time.
  • After 1-2 minutes, clean the surface.

Where the molten lead was poured, a hole is formed. And the glass will not be damaged.

Drilling large holes in metal: methods and tools

Drilling holes, which exceed 20 mm in diameter, in the presence of traditional tools and equipment is always a problem. For thick sheet metal in the construction they often use autogenous cutters, which do not allow to obtain high quality and accurate holes. Gas flame cutting machines may also be used (with practically the same success). Meanwhile, even a hand-held electric tool can be used to make large diameter holes, not to mention the alternative processing methods.

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Why mechanical methods sometimes do not work

In mechanical engineering, holes with a ratio of diameter to material thickness of 1 or more are considered large. Practically in the construction it is problematic to make a hole with a smaller dimension ratio. The reasons for this are:

  • Difficult heat removal from the drilling area, resulting in severe tool overheating.
  • Problems with the removal of shavings.
  • Significant axial loads on the feed mechanism (in machine drilling), or on the hands of the worker. in manual cutting.
  • A sharp increase in feed can lead to a drop in the speed of the electric motor and its rapid failure.

Let’s add that the durability of drills (even carbide drills) in this kind of metal drilling is also unsatisfactory. Less difficult to drill large diameter holes in wood workpieces, but also difficult to remove chips.

On the other hand, drilling (especially in terms of single production) is characterized by minimal costs for the necessary tools and equipment. The following techniques are commonly used:

Rim boring with small-diameter holes, which are aligned with the main hole. The gaps are eliminated by subsequent sawing away of the surplus metal. The method is extremely low-productive, so it is useful only for single jobs of this kind.

The use of tapered drill bits that have multiple annular zones of a specific diameter. The drill bit is plunged into the metal, and the hole is gradually drilled to larger diameters. The disadvantage of this option is that such drills are very expensive, and therefore cost-effective for a large amount of relevant work.

Core drilling, which drills out only a ring-shaped volume of metal, and leaves the main part without mechanical action. The method is not only highly productive, but also leaves the drilled metal for reuse. the waste can be used as pads, supports, welded bed bases, etc.

All these options are also used for deep drilling, when the same difficulties are waiting for the worker. heat of the tool and problems with chip removal. Here it is necessary to ensure a good heat removal from the metal workpiece, so the use of lubricants-coolants, as well as drills equipped with hard-alloy plates is mandatory. The reason is that such materials have a lower thermal conductivity and, on the contrary, a higher thermal resistance than all tool steels that are used for the tool.

Recommendations for cutting metal pipes

Cutting of pipes of different metals is a popular operation during repair and construction works. It is necessary to cut off products during installation of sewage and heating systems, water pipelines. In this direction, the angle grinder does well in a variety of tasks. Blades for work are chosen according to the material from which the pipe is made.

The use of an angle grinder makes it possible to:

  • To cut pipes at different angles, e.g. 45 and 90 degrees;
  • Cut products with large diameters;
  • evenly cut profile (rectangular or square cross-section) pipe;
  • make longitudinal cutting of tubular blanks;
  • sawing cast iron pipes;
  • Cut thin-walled pipes.

If you need to cut a large-diameter pipe, then the use of an angle grinder allows you to perform this work without significant monetary costs. But the productivity is low and the risks are considerable. When long pipes are supported, only the overhanging parts are sawed off. If you cut in the center, the cutting edges will jam the cutting wheel, which leads to jamming of the tool and possible injury.

Specialists not only cut pipes from different materials at desired angles, but also cut holes in them in the desired shapes. Work with shaped and round workpieces is performed in a similar way, with the mandatory observance of safety rules.

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sawing pipes at different angles

To cut at an angle of 45 and 90 degrees round and profile pipes is necessary when laying various communications. In any case it is necessary to saw off the tube evenly, so that the elements that need to be connected are tightly connected to each other as possible.

Cutting at an angle of 45 degrees of cylindrical cross-section pipes is carried out as follows

  • take an ordinary square paper sheet;
  • Fold it exactly diagonally;
  • with this template wrap the pipe;
  • with chalk or other marking device draw the future line for the trimmer of the cut;
  • remove the template;
  • clamp the workpiece in a vise;
  • cut off the marked fragment of the pipe.

When laying the template any of the two short sides of this triangle must be parallel to the central axis of the pipe.

When it is necessary to make a cut at an angle of 90 degrees, pipes are simply wrapped in a circle (cylindrical) or around the perimeter (profiled) with a sheet of paper. After that, mark the line for the trimmer of the cut. It is also very easy to mark out a profile pipe using a standard square.

If it is necessary to cut at an angle of 45 and 90 degrees a significant number of profile pipes make appropriate templates of this material, only with a larger cross section. This allows you to perform the required measurements only once. To make an initial marking they use a construction angle or a protractor. When the template is made, the workpieces to be cut are inserted into it, marking the cut lines. Then sawing is performed.

Templates are also made for other angle sizes. Such a method increases labor efficiency.

Peculiarities of cutting cast iron and thin-walled pipes

Cast iron is a fragile material. To saw a cast iron pipe with an angle grinder, act in this sequence:

  • Mark the line for the trimmer of the cut;
  • put a wooden bar under the pipe, which will support it;
  • make a kerf on the contour to a depth of a few millimeters;
  • insert a chisel into the made cavity;
  • hit the set piece hard and sharply with a hammer.

After the impact the pipe will split along the kerf line. Its edges will be fairly flat. If necessary, they must be machined additionally.

To make a longitudinal sawing of a pipe, it is also important to accurately mark. To apply it, they use various devices, such as construction thread (“chipping”). The entire sawing process must be performed carefully, slowly, so as not to lose sight of the marked line.

Thin-walled pipes are one of the varieties of this type of product. They are often made of non-ferrous metals: copper or aluminum. They are difficult to cut. In this case it is necessary to use grinding wheels appropriate for the material of the workpiece.

Sawing thin-wall tubing needs to be done very carefully because it can easily become deformed even by applying a light load.

To reduce the probability of bending the cut part, it is filled inside with various loose fillers, such as ordinary purified sand.

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