How to cut a square hole in metal

How to make a square hole in wood?

In its own design device device for drilling a square hole is faster mill, not a drill. But Russian craftsmen are more accustomed to call it a drill, and manufacturing companies call the product specifically so.

According to the kinematics, in accordance with which occurs the movement of the device, of course, that the processed material is cut only by the side surface means, but more precisely. 4 such surfaces. This method is typical not for a drill, but for a cutter. But rotary movements are not enough to drill a high-quality and even square hole. The cutter should not only rotate, but also make swinging movements. also around the axis.

It is also of principle that rotation and oscillation should be oriented in reciprocal directions.

With what speed drill cutter will rotate, you can only know, based on the features of an electric drill or other tool, which is planned to work. But it should be taken into account that drilling a square hole will not be very fast, and the productivity of the work will be low.

The 1st triangle of the drill is not enough to get a square hole. it is necessary that the drill has a groove, which will be carried out removal of chips, which is the waste from drilling. For this reason on the working surface of the drill is cut out 3 semi-elliptical circles.

Because of this the inertia moment of the cutter is reduced, the load on the spindle is minimized, while at the same time there is an increase in the cutting ability of the nozzle.

How to drill the hardened steel at home with an ordinary drill

Normal steel or any other metal is easy to drill, using standard drills of quick-cutting material. Drilling through hardened steel is another matter: here you have to do a lot of work. After hardening the workpiece becomes unusually strong, and the question arises how to drill a hole in a hardened metal, because the usual drill in this case can little help.

Experts recommend making holes in the parts until the moment when the hardening occurred. You can also try tempering the steel, then perform drilling and harden the material again. If it’s economically and technically feasible, you should do it, but in some cases it’s simply impossible to do otherwise than to proceed to obtain a channel on an already hardened surface.

There are several ways to drill holes of any diameter in hardened steel. These methods can be implemented with great success both in production and in the home workshop.

Drilling a hole in hardened steel

The widespread question of how to drill through hardened steel can be attributed to the fact that with conventional technology, the tool quickly dulls and becomes unusable. That’s why you need to pay attention to the features of hardfacing drilling. Among the peculiarities of the technology, we note the following points:

  • It is necessary to properly prepare the hardened workpiece.
  • In some cases, a special tool is required.
  • Coolant is used.

If necessary, you can make a drill bit for hardened steel with your own hands, which requires certain equipment and skills. However, in most cases, a purchased version is used, as it will do a better job when cutting hardened steel.

The nuances of drilling

The technology under consideration has quite a large number of features that need to be taken into account. Drilling of hardened metal is carried out with the following points in mind:

  • Before carrying out the work, attention should be paid to the hardness of the surface. According to this parameter the choice of the most suitable drill bit is made. You can determine hardness using a variety of techniques.
  • Large quantities of heat are released during drilling. This is why the cutting edge wears out so quickly. For this reason, in many cases a coolant is supplied to the cutting zone.
  • When cutting hard-to-machine material, the cutting edge must be resharpened from time to time. A regular sharpening machine or a special tool is used for this purpose. Only a diamond wheel is suitable as an abrasive.
See also  How to cut a hole for a power socket in the apron

There are a variety of methods of cutting hardened steel. Some of them considerably simplify the machining process. Only when all the details are taken into account is it possible to improve the quality of the resulting hole.

Good drilling techniques

Many different techniques can be used for working with hardened steel. The most common technologies are characterized by the following features:

  • Surface treatment with acid. This technique is characterized by a long application time, since it takes quite a long time to reduce the hardness of the surface. Sulfuric, perchloric or other acid can be used for etching. The procedure involves creating a bead that will contain the applied substance in the cutting zone. Metal becomes softer after prolonged exposure, it is possible to drill with the conventional version.
  • It is possible to use a welding machine to achieve the goal. Metal becomes softer when exposed to high temperature, which greatly simplifies procedures.
  • A special drill bit is used most often. Versions available on the market that can be used for processing hardened steel. They are made of metal with high resistance to wear and heat. However, the complexity of manufacturing and some other points determine that the cost of special tools is quite high.

In addition, a puncher is often purchased to achieve the goal. It can be used to make a small hole, which makes further drilling easier.

Particular application features of drills for square holes

Standard Watt’s drills, designed for drilling square holes in metal, are made of U8 steel. Hardening is carried out until the hardness of the tools is between HRC 52 and HRC 56. Tools made of alloyed steel X12 are used in heavy applications. Hardness of the material ranges from HRC 56 to HRC 60.

The most important feature of these drills for square holes application in production and household is the need to use additional devices for fixation of tools and moving the working parts by the above-described trajectory.

What is used in manufacturing

For fixation of drills for square holes in metal on the machines are used special spindle adapters. They consist of:

  • housings;
  • gears;
  • adapters for the main spindles;
  • drive gears;
  • gears of the meshing;
  • Shaking sleeves.

04_Drilling a square hole in metal on a machine.jpg

Picture : drilling a square hole in metal on a machine tool

What’s used in the home

When using drills, drills for square holes are fixed with special frames. They are connected to the cartridges by gears. Special adapters are used for this purpose, consisting of:

Image : the principle of obtaining square holes with Watts drills at home using conventional drills

How to cut a square circle out of metal using an angle grinder

You can cut an even circle from a sheet of metal with an angle grinder (angle grinder). However, for a better cut you will need a device, which is not difficult to make your own hands.

In this review, the author shows two ways to cut a straight circle out of metal with an angle grinder.

For the first method will need to make a simple swivel stand with a magnet for the angle grinder.

Recommended reading: homemade machine from angle grinder for cutting blanks from metal.

The main steps of the work

The first thing to do is to make a mount for the angle grinder. For this, the author cuts two metal plates, drills holes in them and fastens them to the gear housing with bolts.

See also  Welding welding and metal cutting

After that, you will need to cut another plate and weld it to the first two plates.

Next, the author welds a steel strip to the resulting mount, the end of which is fixed to the body of the angle grinder with a clamp.

A bolt will need to be welded to the angle grinder mount (in the center of the top plate).

In the next step, the author cuts a piece of round tube. On the tube you need to put a sleeve (from a pipe of larger diameter) with a fixing bolt, and to the ends welded nuts. The author welds two pieces of tubing to the sleeve.

Next you need to make another bushing with a retainer. It must be welded to a round magnet (can be removed from an old speaker).

Then you can begin assembling the device. For convenience, the author screws the handle from the angle grinder into the tube. We put a rack on a sheet of metal, set the necessary size and it is possible to cut a circle.

The process of making a turntable

There is also a second way to cut the circle evenly. To do this, use a previously made stand, and you will need to make a turntable.

First the author cuts a piece of round thick-walled tube, into which two bearings need to be pressed and welded.

After that a piece of pipe with bearings will need to be welded to a square plate. Drill four fixing holes in the plate.

The author fastens the base of the turntable to the workbench using screws.

Next, the author disassembles the second round magnet. A piece of steel round bar, the diameter of which is equal to the inner diameter of the bearings in the tube, should be welded to the metal plate.

Then a magnet has to be glued back to the plate (the author uses a quick-drying glue for this).

The author cuts a circle out of a sheet of metal. In the center a magnet is placed with a metal rod. After that you need to weld four pieces of shaped tube to the round bar.

In each piece of the profile one must drill a hole and then weld nuts.

The author screws bolts into nuts. Then pieces of a round rod are welded to the bolt caps (pieces of a square can be used). We insert the profile pieces of a smaller diameter and fix them.

The turntable is attached to the base, bolted to the table. On top of the author puts a sheet of metal, and then sets the rack with an angle grinder.

about how to cut a straight circle from metal with an angle grinder, you can see in the video below.

Watt’s drill

There is a way of drilling a square hole on a drilling machine equipped with a special fixture. The method is based on the use of the Watts drill, the cross-sectional shape of which corresponds to the triangle of Relo.

If this tricky triangle is rotated around its center, and the center will move along its circular path, the tops of the triangle will draw almost a square when moving. Only the corners will be slightly rounded. They must be filed. The Watts drill can be mounted on a lathe and drill square holes in workpieces of any thickness. Only between the chuck of the machine tool and the drill bit it is necessary to install special devices.

Principle and construction of the Rhelo triangle

Relo triangle is a flat geometric figure. It is formed by joining the vertices of an equilateral triangle by arcs of circles drawn from each vertex of the same triangle.

The peculiarity of the Rhelo triangle is that its vertices describe the trajectory of an almost perfect square when making a rocking motion.

The only disadvantage of such a rotation of the triangle Relo is that in the corners of the square there are small roundings.

If you want to get a square hole with internal angles of 90 degrees it needs to be reworked. It can be done manually with files and rasps, or on a chisel mill.

Problem statement

You need a through hole in the cylinder with minimal dimensional inaccuracy

The disposition is as follows. There is a cylindrical metal workpiece, and you need to make a hole in it for a square rod.

See also  Husqvarna 128r stalls when you press the gas

For this we need a lathe. Cutting and milling disc and cutter. For this application we used a VK-8 cutter. We also need a welding inverter.

How to bend a square tube?

Bent profile pipe. a mandatory element in the construction of gazebos, sheds, greenhouses, fences, even garages. Large section thick-walled profiles are used when erecting roofs of buildings. How well the profile is bent depends on the reliability and appearance of the erected structure.

Drilling holes in metal. 7 tricks. You might need these

You might not often have to drill in metal, but knowing these rules will make it a lot easier and save you a lot of time.

The first tip might seem trivial, but you don’t have to disregard it.

1.Kerning the drilling point

Metal must be core-drilled before drilling. This is to keep the drill from slipping sideways. The harder you core, the less wiggle the drill bit gets.

2.Drill speed and diameter

The smaller the diameter of the drill bit, the higher the RPM should be. This way the drill bit breaks less. This rule is almost always valid.

3.Cool the drill bit

Use coolant(coolant). oils, emulsions. If there is no special coolant, you can use plain water, which is better than nothing. Especially if the depth of drilling is deep and the drill bit gets very hot.


Keep an eye on the sharpening of the drill bit, if it makes a whistling sound when drilling then it has dulled.

There is no point in continuing to drill with it, you will ruin the drill bit permanently. Turn and go on working.

5.The marking

The marker is as useful for through holes as it is for blind holes.

We find it easier to control the drilling depth when we are drilling blind holes.

For through holes, we can see when the drill comes out (a dangerous and important moment!)

Use a marker or masking tape to make a mark on the drill. Or. if the machine has a stop, set the desired depth.The reticle lets you know how far you have left to go so you don’t drill deeper into the workpiece than necessary.

Clamp the workpiece

If it is not done, the accuracy of drilling will decrease, especially with light weight parts, and there is a chance that the drill bit will “bite” and the part will “wrap” on it, and it is fraught with injuries and spoiled product.

7.Control the output of the drill bit

When drilling with small drill diameters on the “exit” we are at least at risk of breaking the drill. At most, you get a splinter and a cut from the flying splinters of the drill bit. The cuts are severe, and retrieving the drill bit is no fun.

Eye contact with such splinters can cause loss of eyesight!Therefore, it is always worth working with goggles!

When drilling with a drill of relatively large diameters (8-10 mm and above). be careful. There is a risk break your arm.Therefore!

First: It is desirable to drill at low speed.Secondly: be especially careful where the drill bit comes out of the outside of the workpiece. The drill bit can get bent. If you are not careful, the turning force can break your hand. This is no joke!

I hope this information has been of interest to you.

Our readers also liked these articles:

How to work on hard to reach surfaces? What to do if you do not have a grinding wheel for your drill?What to do. The drill bit should not rotate in the chuck of the drill or screwdriver?How to drill a 12 mm hole with a 10 mm drill bit?

| Denial of responsibility | Contacts |RSS