How to make a square hole in metal? -

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Alexander Korovaev 03/16/2020

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There are no problems with the formation of round holes in metal products. But how to make a square hole? There are not many ways.
And the first of them is the use of a laser, the second thing that comes to mind is the use of special Watts drills, which use the principle of the Reuleaux triangle.
However, there is another way.

Operating principles and design

In order to drill a square hole, a Watts drill is usually used, the design of which is based on a geometric figure such as the Reuleaux triangle. One of the most important features of such a figure, which represents the area of intersection of three equal circles, is the following: if a pair of parallel reference lines are drawn to such a triangle, then the distance between them will always be constant. Thus, if you move the center of the Reuleaux triangle along a trajectory described by four ellipsoidal arcs, its vertices will draw an almost perfect square, with only slightly rounded vertices.

Property of the Reuleaux triangle

The unique properties of the Reuleaux triangle made it possible to create drills for square holes. The peculiarity of using such a tool is that the axis of its rotation should not remain in place, but move along the trajectory described above. Naturally, this movement should not be hindered by the equipment cartridge. When using such a drill and the appropriate equipment, a square hole is obtained with perfectly straight and parallel sides, but with slightly rounded corners. The area of such corners not processed with tools is only 2% of the area of the entire square.

History of the instrument

The design of the Watts drill is based on the Reuleaux triangle. To obtain such a figure, you need to draw an equilateral triangle and three circles. Their centers are located at the corners of the triangle, and the radius is equal to its side. The result is a triangle with rounded sides. An engineer from Germany, F. Relo, noticed that with certain methods of rotation, the new figure’s trajectory is as close as possible to a square.

Reuleaux triangle:

In 1916, Watts filed a patent for a special device. His technical development ensured that the drill moved in such a way as to guarantee square-shaped holes.

Watts drill:

Operating principles and design

Property of the Reuleaux triangle

Types and their structure

are most often used to drill square-shaped holes . The peculiarity of their design is that they are based not on a square, but on a triangle, called the Reuleaux triangle. The operating principle of the drill is as follows: the triangle moves along ellipsoidal arcs, and with its vertices it will outline a square of an ideal shape. The only drawback can be considered the slight rounding of the vertices of the 4-gon. A square will be obtained if there are 4 ellipsoidal arcs, and the movement of the Reuleaux triangle is uniform.

It should be noted that the Reuleaux triangle is a structure unique in its properties. Only thanks to him it became possible to create drills for drilling holes in the shape of a square. When operating this product, it is important to remember that the axis along which it rotates must describe ellipsoidal arcs and not stand at one point. The design of the equipment chuck must be such as not to interfere with the movement of the triangle. If the triangle moves clearly according to the rules, then the result of drilling will be an even square, and processing will not affect only 2% of its total area (due to the rounding of the corners).

Geometric parameters

The main geometric parameters include the following indicators:

diameter indicated in mm;
total length, mm;
length of the working part, mm;
sharpening angle in degrees.

In addition, when choosing a square drill, pay attention to the shank, which must match the tool spindle or a set of devices for fastening it. Drilling square holes must be done after preliminary marking and punching the center of the future hole. It is recommended to start drilling at low rotation speeds, and then switch to the speed indicated in the data sheet of the machine or tool.

Drill or cutter?

The majority of the technical community believes that it is still a milling cutter. However, manufacturers stubbornly continue to call this tool a drill for square holes, a Watts drill, or a drill whose profile corresponds to the Reuleaux triangle.

Which is more correct? If we turn to the kinematics of movement of such a cutting tool (for clarity, you can use the diagram shown in Fig. 1), you will find that metal removal will be carried out only by the side surface, and there will be not one cutting plane, like a conventional drill, but four, which more typical for cutters.

However, a single rotating motion will not be enough to obtain a square hole. Simple mathematical calculations (not given in this article) show: in order for a “drill” for a square hole to perform its function, during operation it must describe not only the basic rotational movement of the cutting edge, but also the rocking movement of the drill/cutter around a certain axis. Both movements must be made in mutually opposite directions.

Read also: Mass of a spring pendulum formula

Figure 1 – Reuleaux Triangle: a) – construction; b) rotation sequence to obtain a square-shaped hole.

The angular velocity of both rotations is determined quite simply. If we take the rotation frequency of the drill shaft (or hammer drill) as the parameter f, then a speed of 0.625f is sufficient for oscillatory rotations of the spindle around its own axis. In this case, the spindle axis is, as it were, clamped between the working shaft and the drive wheel, causing the drill/cutter to oscillate in the clamping device with a residual speed

(1 – 0.625)f = 0.375f.

The resulting rotation speed of the cutter can be more accurately determined using the technical characteristics of the drill/hammer, but it is clear that it will be much lower than that for which the tool was originally designed. Therefore, obtaining a square hole will occur with less productivity.

How to cut round holes

Using Boolean logical operations

We have already discussed this method of cutting a hole in an object in great detail in this lesson. The method is really good in its simplicity, but the mesh after manipulation with the Boolean may turn out to be “curve”. Sometimes using ProBoolean can help solve mesh problems.

Using ProCutter

This tool allows you to make holes in much the same way as Boolean. We create an object in which we will cut holes, and an object, or several, that we will cut out. I have two cylinders.

Now select the large cylinder and apply ProCutter to it. Click Create – Compound – ProCutter.

We select the large cylinder, enter the settings as in my screenshot, then, with the Pick Stock Object button pressed, select the objects that we will subtract.

We get perfectly round holes.

"Manual" method

This method allows you to more accurately fit the circle into the 3-D model grid, but you will have to spend much more time. Create a sphere using Standard Primitives and convert it to Editable Poly.

Let's switch to Vertex mode and check the box next to Ignore BackFacing, this way we won't accidentally catch points on the other side of the sphere.

Mark any grid square, select its three vertices (as indicated in the screenshot) and connect them with a diagonal using Connect. We create two diagonals using this method.

Select a point at the intersection of the diagonals and press the Champfer button, enter the radius.

Go to the Edge level and select two opposing grid lines, then click the Connect button, set 4 segments.

We do this with all the edges adjacent to the circle.

Let's switch to the Vertex points mode; we should have selected points belonging to the future circle. Add the Spherify modifier.

We get a round hole. Now we can convert the object, for example, to Editable Poly, in order to manipulate it.

Using Loop Regularizer

Another way is to use the free Loop Regularizer script, which you can . Download it, then drag the saved file into the open 3D Max window.

I’ll tell you how to use the script with an example. Create a rectangle, give it two segments in height and width. Convert it to Editable Poly. Go to the Edge editing level and double-click to select all the edges dividing the rectangle in half in the vertical plane.

Press the Chamfer button, set the number of segments (the more, the more rounded the hole will be), set the distance.

Now we will do the same for horizontal edges.

Go to the Polygon level and select all the polygons in the center on both sides of the rectangle.

Right-click on the screen and select the Regularize line that appears after installing the script.

The square has transformed into a circle. As I already said, it would have been smoother if we had specified more Chamfer segments.

Now press the Bridge button and get a through hole.

Electronics for everyone

I think each of you made a case for your electronic craft. And when making a body, one nasty problem often arises - making a hole with a shape other than a circle. For example, square, under an LED indicator.

I used to suffer for a long time, drilling along the contour, then grinding these teeth, cursing about the fact that I sanded off too much or messed up the parallelism. In general, I have my hands full on everything related to the machining of materials. And there is nothing to be done about it. But where the hands cannot, the head must work. And we came up with a simple and effective solution.

So. You need to make a square hole in the plastic case. First, let's mark the hole. It is better to do this using a paper template - you need to mark the corners as clearly as possible. We do this on the outside, front side! Then the corners are drilled through with a thin drill. Here it is important to take a thinner drill. The thinner the hole, the more accurate our hole will be.

Take a ruler and a sharp scalpel. You can use a utility knife or whatever you have on hand. The main requirement is that it must be very sharp, rigid and not loose. I make things like this with an X-Acto

Using a ruler from hole to hole, exactly according to the size of our hole (no more, no less, exactly the same!) we make cuts. The deeper the better, but without fanaticism. Because The deeper you cut, the greater the chance that the blade will break off and we will scratch the outer surface, but this is no longer the same - it’s ugly. The holes here also rule because the tip of the scalpel falls into them and the edge of the cut does not go further than the hole. Marking is the most important stage

. It depends on him whether everything will turn out perfect the first time or whether it will have to be trimmed.

I cut it, now I need to shred the inner surface of the hole into 4 parts, under the St. Andrew's flag. This is already anything. I usually don’t stand on ceremony - I take a dull drill, which is no longer a pity. I stick it in and, like a milling cutter at high speeds, I gnaw through the side of the plastic from corner to corner.

That's it, we got four pieces inside. Now you need to pick them up from the center and break them inward

The cut we made will give us a weak point at which the plastic will burst and break. And the holes at the edges will prevent the crack from going further than it should.

Do you see how clear and even the break is?

One two three four - we got an exact rectangular hole that does not need to be leveled or polished. Well, maybe a little bit, if I messed up with the markup - like I did now :(.

It took me no more than 10 minutes to pick this hole. This includes cleaning up trash and being distracted by taking photographs and searching for a scalpel or a drill.

Z.Y.

I made this hole here purely for the sake of photos, on an unnecessary body, so don’t look at the fact that its “horizon is blocked” and the markings are crooked - I didn’t try

Square Hole Drilling Tool

To drill square holes, special Watts drills are used. They differ from conventional tools in having working parts that have a special design. It is based on the Reuleaux triangle.

Image No. 1: Reuleaux triangle and its properties

This figure represents the intersection of three equal circles. The most important property of the Reuleaux triangle is that if you draw a pair of parallel reference lines to such a triangle, then the distance between them will always be constant. As you can see in the figure above, if you rotate the Reuleaux triangle along a trajectory described by 4 ellipsoidal arcs, you get a square with slight roundings at the corners.

Reuleaux's developments were used by the English engineer G. Watts. It was he who created the drill for square holes, named after him - the Watts drill. The working part has this profile.

Image No. 2: Watts drill and the profile of its working part

How to drill a square hole without a special drill

To drill a square-shaped opening in the material, it is not at all necessary to use a special drill for this. Before special attachments appeared, craftsmen used a simple, proven method. This method involves using regular drills for metal or wood (depending on what material needs to be processed). If there is a need to drill a square hole, but there is no special drill, then the process can be implemented in the following way:

Initially, you need to mark the future square on the surface of the material
After this, at the corners of the marking with a core, mark the points along which round holes are drilled
After drilling through holes around the perimeter of the marking, it is necessary to use a drill of such a diameter to remove the inner part by drilling
Next, all that remains is to work with a file to align the corners of the resulting square

This procedure is not at all difficult, but it takes a lot of time.
However, it is an excellent alternative to square drills, after which you also need to use a file to straighten the corners. This method of creating square openings is very popular and is used even today. If you need to quickly make a square hole in a workpiece, then you need to drill an initially round hole, and then use a file to sharpen the edges and obtain the desired shape. This is interesting! The advantage of this method is that in this way you can get square openings of different sizes. To drill square openings of different sizes with special drills, you will need to have attachments of the appropriate parameters at your disposal.

Classification of drills for square holes

In modern metalworking, almost all cutting tools that are used to produce square holes work on the principle of rotation of the Reuleaux triangle. A Watts drill (or as it is sometimes called a Reuleaux drill) allows you to make square holes of various sizes in metal parts of various thicknesses. This tool is classified according to its size, material of manufacture, and shank design.

A Watts metal drill must be made of high-speed steel. This tool is marked HSS (High Speed Steel). For domestically produced tools, tool steel U10 or alloy steels X12 and X12MF are used. The hardness of the tool should be between 52 and 60 HRC. A square drill can have different diameters depending on the size of the side of the square.

Note that buying a Watts drill is quite difficult. Don't expect it to be available in every hardware store. You may have to purchase it to order from a large tool store or buy it from an online store.

Choosing a cutter for drilling square openings

What difficulties may arise when choosing a drill for a square hole? It would seem that no difficulties would arise at all. You just need to come to the store and tell the seller the size and shape of the opening that you want to get in the end. When purchasing a slotting cutter, you will need to pay attention to the following technical parameters:

Manufacturer - the devices in question are manufactured by all modern companies, not only domestic, but also foreign. The prices of such drills differ depending on who the manufacturer is. The high cost of a product does not always indicate its quality, so you need to choose depending on how often you plan to use the nozzle. If often, then it is better to give preference to products from the manufacturer Rapid. Chinese nozzles are cheaper, so they are not designed for long-term use
The length of the drill depends on how deep the opening needs to be in the end. The most common options for cutters in length from 160 to 225 mm
The size of the square hole - it all depends on the task at hand. Depending on the size of the mandrel, the nozzles have corresponding parameters. You need to understand that this is one of the main parameters. The nozzle bit always has a smaller diameter than the mandrel size
Shank type - it is important to pay attention to this parameter, since it will not be possible to secure a drill with a tapered shank in a drill chuck
Purpose - depending on what material is planned to be processed - steel or wood. For steel workpieces, products made of high-alloy and high-speed steel are used, and for wood, nozzles made of carbon steel are produced

Drill size	d, mm	B, mm	L, mm	C, mm	D, mm	E, mm
6x6	4	45	160	115	6	19
8x8	5,7	50	205	135	8	19
10x10	6,8	50	205	140	10	19
12x12	9,5	70	210	140	12	19

Based on the above parameters, you should select drills for square openings.
First, decide on the size of the required hole, as well as its width. This is interesting! To drill square holes in metal workpieces, it is recommended to use specialized equipment. You can drill a hole in a wooden part with a drill, but you must use a holder.

How to use?

When using Watts drills, there is no need for special machines with attachments. A regular machine is sufficient if you plan to work with metal. As for the wood taken as the material to be processed, an ordinary drill is enough to drill holes in it, albeit slightly improved with the help of additional devices.

To make such a device, you need to follow a number of steps.

First of all, you need to get a sheet of plywood or a wooden board , but not very thick. Of course, you will also need the Reuleaux triangle itself with geometric parameters corresponding to the diameter of the Watts drill used.
Firmly fix the drill on the resulting triangle.
To move the triangle with the drill attached in accordance with the desired trajectory, you will need a wooden guide frame. A square hole is cut inside it, the parameters of which are the same as those of the hole that is planned to be drilled. The thickness of the frame is very important - it determines how deep the hole can be drilled.
The frame must be clearly fixed in the drill chuck so that there is complete coincidence of the center of the triangle and the axis along which the electric drill chuck rotates.
The rotation of the drill must be correct. To do this, it must move freely along and across. To ensure this, a transmission mechanism is needed, which will connect the electric drill chuck with the shank of the nozzle. The operating principle of the transmission mechanism is the same as the driveshaft in any truck.
Fastening the wooden workpiece must also be careful . Position it in such a way that the axis of rotation of the nozzle clearly coincides with the center of the planned square hole.

The design of the adapter (transmission mechanism) is simple. It has a body, a floating shank, a special oscillating ring, mounting screws and support balls. A special feature is the replaceable bushing - it is needed so that you can secure the chucks of various metal processing machines . You can change the nozzle quite quickly.

Once the assembly of the device is completed and each element is fixed, the electric drill is ready to start drilling. Yes, the corners of the hole will not be equal to 90 degrees, but will be rounded, but this is a solvable problem. The roundness is finished with the most common needle file. It must be remembered that such a device is applicable for working on wood, and on sheets that are not too thick. This is due to the fact that the structure itself is not very rigid.

Making a punch

On the reinforcing rod, one of the sides (round) is marked in the form of an “inscribed” square of the required dimensions. Next, the reinforcement is clamped in a vice parallel to its “jaws” and, using a grinder, is ground on 4 sides to the required size. To obtain maximum accuracy, a caliper is used, which makes it possible to check the current size of the part.

Having made a square-type workpiece on a piece of reinforcing bar, it will be necessary to “sharpen” it in a special way, using a very small grinder circle and a round file. It will be necessary to vertically fix the part in a vice, and gradually create a semicircle between the adjacent vertices of the square. A round depression should form in the center of the end part of the product.

After the tops of the square (the end part of the part) have become sharp “spires”, it will be necessary to fix the part horizontally in a vice, and harden the part using a regular propane torch, with which the square part of the product is heated until reddened, and then cooled with water.

After such processing, the square part of the part (punch) becomes stronger and more rigid.

Work order

Large square hole

Many have already guessed what the approximate list of work will be as soon as they found out the tool required for the job.

1 The idea is as follows. A rectangular cut is formed longitudinally in the workpiece, the width corresponding to the size of the side of the square being drilled. The depth is selected taking into account the dimensions of the workpiece so that the center of the future square coincides with the axis of the cylindrical workpiece.

2 Then a metal jumper is installed over the cut, which will need to be scalded.

3 To give the product a marketable appearance, it should be processed after welding on a lathe.

So, let's start practicing.

Step No. 1 - shaping the cut

Make a cut with the width of the side of the square

1 For cutting, it is better to use a cutting disc. This will speed up the work significantly. Don't forget about oil.

The cut is milled

2 We change the disk to a milling one, since the correct geometry of the square hole is needed.

Step No. 2 - forming a jumper

Trying on a jumper

1 Place a square rod in the cut you made. We put a metal jumper on top. For the latter we use a segment of a similar rod.

Fixing the workpiece in a vice

2 Using a vice, fix the workpiece prepared for welding.

Step No. 3 - welding and primary processing

Welding work is completed

1 We grab the jumper at a couple of points and remove it from the vice. We thoroughly boil the structure.

Welding needs to be annealed

2 So as not to think, we anneal the welding seams.

Step No. 4 - machining on a lathe

Processing of the first part

1 A VK-8 cutter was used for processing. We expose the workpiece. To do this, I had to process it a little with a file.

We expose and trim

2 Turn the product over. We expose and trim the workpiece.

Clamp and process

3 Clamp and process for finishing.

A little history with geometry

Back in the 15th century, the legendary Leonardo da Vinci, while studying the properties of geometric figures, drew attention to the so-called geometric objects with equal thickness. There are an infinite number of such figures, but the simplest - besides a circle - is a rounded triangle, which can be formed as follows. An equilateral triangle is drawn, each of the corners of which is connected by an arc of a circle drawn from the center of the opposite side. The peculiarity of such a triangle will be that all its sides will have a constant width, which is equal to the length of the side of the original equilateral triangle.

L. Euler drew practical benefit from this fact, who three centuries later demonstrated the rotation of such a rounded triangle: first around its own axis, and then with some eccentricity, since the cardan mechanism was already known to science and technology of that time.

Features of drilling square holes in wood

In furniture production, parts are often connected using a tongue-and-groove system. This connection assumes the presence of square grooves in the supplied parts. To make holes in wood, use a special square wood drill. It is a set of slotting tools. It consists of an internal wood drill and a chisel that fits onto it. Typically, the drill diameter ranges from 6 to 18 millimeters. The shank usually has a diameter of 19 millimeters. Such kits can be installed on slotting and drilling machines.

Operating principle and design of the Reuleaux triangle

The Reuleaux triangle is a flat geometric figure. It is formed by connecting the vertices of an equilateral triangle with circular arcs drawn from each vertex of the same triangle.

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

The only drawback of this rotation of the Reuleaux triangle is that small roundings remain in the corners of the square.

If it is necessary to obtain a square hole with internal angles of 90 degrees, it will have to be modified. This can be done manually using files and rasps or on a slotting machine.

Alternative options for making a square hole

Although the Watts drill is the most productive and accurate tool for making square holes, there is more to be said about how to drill a square hole using other methods.

There are several good methods for this. When working with square drills, the resulting hole in the workpiece will have small radius roundings, which then need to be eliminated by other operations. In addition, there is no possibility of working with parts of significant thickness.

Let's take a closer look at these methods:

In production conditions, the most accurate finishing method for cutting a square hole is laser cutting. But for this it is necessary to have expensive complex CNC machines in the equipment park.
Another method is to drill a round hole in the part with the diameter of a circle circumscribed by a square. Then the corners of the hole are welded with the template inserted. This method requires a welding machine and appropriate skills.
In mass production conditions, when working with sheet and thin-walled metal, square holes are produced by sheet stamping. In single production this is not relevant, since it requires the manufacture of cutting or punching dies.
When working at home, if you need a square hole that is not very small in size, then you can drill it in the following way. A round hole with the diameter of a circle inscribed in a square is made in the part using an ordinary metal drill. Then the imaginary corners and edges of the square are straightened using a file and chisel.
For working with thin metal, special square punches are also available. Their maximum size is 70 by 70 millimeters.

How to make a rectangular hole in a sheet of metal

I'll show you how to make a rectangular hole in a sheet of metal using a hammer and chisel. You will also need a drill and a vice. Large rectangular holes can be cut with a grinder, and small ones with a chisel.

My channel libral1973: https://www.youtube.com/user/libral1973 Machine for sawing wood: https://www.youtube.com/watch?v=hHvT7. Plow tests: https://www.youtube.com/watch?v=SuDZH. Installing a hydraulic pump: https://www.youtube.com/watch?v=0jtL_. Harvesting potatoes with a mini tractor: https://www.youtube.com/watch?v=KdzR4. Planting potatoes with a mini tractor: https://www.youtube.com/watch?v=47vg9. Planting tool: https://www.youtube.com/watch?v=uC_-B. DIY cultivator: https://www.youtube.com/watch?v=frfW6. How to adjust valve clearances: https://www.youtube.com/watch?v=5hPSX. How to shorten a hydraulic cylinder: https://www.youtube.com/watch?v=niH5W. DIY cultivator: https://www.youtube.com/watch?v=frfW6. Do-it-yourself chain-link mesh: https://www.youtube.com/watch?v=oRdGi. Wood lathe: https://www.youtube.com/watch?v=m_kNg. ———————————————————How to send an e-mail: https://My blog: https://

How to make a square hole in metal

Surely you have already heard and seen about the method of drilling square holes using a Watts drill. In this video, the author shows a different method based on the use of a special tool. What to do if you need to drill a hole, but the diameter of the drill is smaller than needed? Roman also has drilling and milling machines and a hand router Laser cutting - Fantastic worlds made of wood Vladimir Fomin Yes, of course it’s cool!

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