How to cut a square hole in wood

square, hole, wood

Features of the

By its design, the device for drilling square holes is more a milling cutter than a drill. However, domestic craftsmen are more accustomed to call it a drill, and manufacturers also call the product that way.

According to the kinematics, in accordance with which the movement of this device takes place, it is obvious that the cut of the processed material occurs exclusively through the lateral surface, or rather, 4 such surfaces. This method is typical not for a drill, but for a cutter. But the rotary motion is not enough to drill a high-quality and even square hole. The milling cutter should not only rotate, but also make swinging movements. also around the axis.

It is also important that rotation and swaying should be directed in mutually opposite directions.

At what speed the drill-cutter will rotate, you can find out only on the basis of the characteristics of an electric drill or other tool that you plan to work with. However, it must be borne in mind that drilling a square hole will not be very fast, and the work performance will be low.

One Reuleaux triangle is not enough to get a square hole. you need to have grooves on the drill, along which chips, which are waste from drilling, will be removed. It is for this reason that 3 semi-elliptical circles are cut on the working surface of the drill.

Due to this, the moment of inertia of the cutter is reduced, the load on the spindle is reduced, while the cutting ability of the nozzle increases.

All About Square Hole Drills

If modern craftsmen do not have problems with drilling round holes in most cases, then not everyone can grind square holes. However, this is not as difficult as it seems at first glance, both in wood and metal. To solve this problem, it is necessary to use special tools and devices. Interestingly, each of them operates on the principle of the simplest shapes of geometry.

We remove the native cartridge

Start assembling parts on a drilling machine.

First, remove the native cartridge from the machine. Its diameter is larger than the diameter of the hole in the bushing holder, so it must be removed. The kit includes a cartridge with a smaller diameter than the native one, so we will use it.

How To Drill a Square Hole! / Super Easy Tip

Now follow the next instruction:

  • Pull out the ejector head (not available on most drilling machine models).
  • Pulling the head all the way out, grasp the cartridge with your hand so that it does not fall out by itself.
  • Hold the chuck with one hand, grip the spindle feed handle with the other and turn it down slightly.
  • Now, with a little effort, lift the handle up. It will hit the chuck cone and it will jump out of the spindle.

In words, the description looks confusing, but in practice everything is quite simple and understandable.

Alternative ways of making square holes

The disadvantage of Watts drills is the presence of radius arcs in the corners of the square, which is not always acceptable. In addition, square hole drills made with a Reuleaux triangle cannot handle thick workpieces. In such cases, EDM / laser technologies can be used, as well as. which is easier. welding or stamping.

Sets of punches for square holes are produced in an assortment of transverse dimensions up to 70 × 70 mm in metal up to 12. 16 mm thick. The kit includes:

  • Punch holder for a punch.
  • Guide bush.
  • Ring travel stop.
  • The matrix.
square, hole, wood

A hydraulic jack can be used to force the punch. The punched hole is favorably distinguished by the cleanliness of the resulting edges, as well as the absence of burrs. A similar tool is produced, in particular, by the Veritas trademark (Canada).

If the household has a welding inverter, a square hole in the steel part can be pierced. For this purpose, a round hole is pre-drilled (with a margin) in the workpiece, then a square of EEG or MPG graphite of the required dimensions is inserted there, after which it is scalded along the contour. The graphite is removed, leaving a square hole in the piece. It, if necessary, can be cleaned and sanded.

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Types and their structure

Watt’s drills are most commonly used to drill holes in the shape of a square. A feature of their design is that it is not based on a square, but on a triangle called the Reuleaux triangle. The principle of operation of the drill is as follows: a triangle moves along ellipsoidal arcs, while its vertices will outline an ideal square. The only drawback can be considered a slight rounding of the tops of the quadrangle. The square will turn out 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 construction that is unique in its properties. Only thanks to him, it became possible to create drills for drilling holes in the shape of a square. When using this product, it is important to remember that the axis along which it rotates must necessarily describe ellipsoidal arcs, and not stand at one point. The device of the equipment holder must be such that it does not 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 the processing will not affect only 2% of its total area (due to rounding of the corners).

Features of drilling square holes in wood

In the furniture industry, parts are often joined according to the thorn-groove system. This connection assumes the presence of square profile grooves in the supplied parts. To obtain holes in wood, use a special square drill for wood. It is a set of slotting tools. It consists of an internal drill for wood and a chisel fitted on it. Typically, the drill diameter ranges from 6 to 18 millimeters. The shank usually comes with a diameter of 19 millimeters. These kits can be installed on slotting and drilling machines.

The principle of operation and design of the Watts drill

Drilling square holes with a Watts drill is based on the principle of the rotational movement of the Reuleaux triangle along a specific eccentric path.

The shape of the drill does not exactly repeat the rounded triangle, but with its cutting edges it fits into its shape.

The drill has such a cut-out shape in order to evacuate chips from the working area, and also to minimize the moment of inertia of the tool. In addition, the reduction in the mass of the tool helps to reduce the load on the spindle of the metal-cutting machine, and the sharpened edges increase the cutting capabilities of the drill.

In addition to the Watts drill, for work, you will definitely need a transitional spindle, which will provide an alternating displacement of the center of the tool and set the path you need for work.

It consists of a transitional mount for connecting to the machine spindle, a ring gear, a drive gear and a gearing gear, as well as swinging bushings. To use a square drill with a household power tool, manufacturers produce special overhead templates with a cardan drive.

Once again on how to drill a hole in glass

How to drill a hole in glass in 10-15 moments. To do this, you will need to sharpen a thin file like a chisel and attach it to a hand drill chuck. Do not forget to let the file cool down only at the moment of drilling, even occasionally sharpening it.

Drilling a hole in the glass

A hole in the glass can be drilled with a carbide drill. The secret to the success of this operation. in the liquid with which the glass is wetted. It is prepared from aluminum alum dissolved in acetic acid, or from a one-to-one mixture of camphor or turpentine. A plasticine roller is built around the drilling space. Liquid is poured into the resulting bath. Glass during processing must lie on soft matter.

Another way to make a hole in glass

Another method for making a hole in glass.
For work, a drill made of hard metal plasticine for the production of a small bath, a combination of equal shares of camphor and turpentine, as well as a piece of dense rubber.

Making holes in glass

There is an ancient, but something now forgotten method of making holes in glass. The space on the glass, where the hole should be, is properly cleaned of dirt and grease with gasoline, acetone or alcohol. Next, moist fine sand is poured onto the washed place and a funnel is made in the sand to the glass with a sharpened stick of the required diameter. Molten solder (lead or tin is acceptable) is poured into the form prepared in this way in the sand. After 1-2 minutes, the sand should be discarded and the solder cone removed. A smooth through hole appears in the glass.

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Drilling a large hole in glass

The drill is made from a piece of aluminum, duralumin or copper tube 40-60 mm long. From the first end, a wood cork is hammered into it to a depth of 20-25 millimeters, and at the other end, the teeth are cut out with a triangular file. A small screw 4-5 mm thick is screwed into the cork so that its smooth part protrudes 10-15 mm. The head is sawed off. They are glued to the glass on both sides along a paper washer with a hole equal to the diameter to be drilled. The glass is placed on a piece of rubber. A little abrasive powder is poured onto the drilling space. Then insert the end of the screw protruding from the cork into a hand drill, lubricate the teeth with turpentine and then start drilling. When the tube goes deep into the glass by at least 1/3 of its thickness, turn the glass over and finish drilling on the second side.

How to make holes in glass yourself

There is an ancient, but something now forgotten method of making holes in glass. The space on the glass, where the hole should be, is properly cleaned of dirt and grease with gasoline, acetone or alcohol. Next, moist fine sand is poured onto the washed place and a funnel is made in the sand to the glass with a sharpened stick of the required diameter. Molten solder (lead or tin is acceptable) is poured into the form prepared in this way in the sand. After 1-2 minutes, the sand should be discarded and the solder cone removed. A smooth through hole appears in the glass.

Cutting round glasses

We offer the possibility of cutting rounded glasses. A roller from the glass cutter is attached to one jaw of the caliper. Another sponge rests on the glass through a rubber washer. The roller is rolled a couple of times in a circle, then 3-4 tangents are drawn with a standard glass cutter, which facilitate chipping of the glass along the boundaries of the cuts. Sharpened edges are cleaned with a file or emery under running water.

Unconventional glass drilling methods

A thin steel drill, heated to white, is hardened in mercury or a piece of sealing wax and sharpened. Then a saturated solution of camphor is prepared, in turpentine, a drill set on a brace is moistened with it, and glass is quickly drilled, which is moistened at the point of convergence with the named solution. This method can drill 1 cm thick glass in less than one minute.

In order to drill a hole in the glass, we recommend that you take a triangular file, dip it into turpentine and carefully drill a hole.

You can also drill the glass on a lathe with a copper rod, grease it with oil and sprinkle it with emery. Particular attention should be paid to the hole when the drilling process comes to an end and only the last thin layer remains, as this can easily crack the glass

Drilling square holes. Watts drill and the Reuleaux triangle principle

Almost everyone knows how to drill a round hole, but not everyone knows about a drill for square holes. In the meantime, you can drill a square hole in both softwood products and harder metal parts. To solve such a problem, special tools and devices are used, the principle of which is based on the properties of the simplest geometric shapes.

Principles of operation and design

In order to drill a square hole, a Watts drill is usually used, the design of which is based on such a geometric figure as the Reuleaux triangle. One of the most important features of such a figure, which is the area of ​​intersection of three equal circles, is as follows: if a pair of parallel support lines is 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, which will have only slightly rounded vertices.

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Reuleaux triangle property

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 above-described trajectory. Naturally, this movement should not be impeded by the equipment cartridge. 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 untreated corners is only 2% of the area of ​​the whole square.

Making a device for drilling square holes

Using Watts’ drills based on the Reuleaux triangle principle, it is possible to drill square holes in metal workpieces, even on a conventional machine that is not equipped with special attachments. For the same, to create a square hole in a wooden part, you can use a regular drill, but for this it must be equipped with additional devices.

You can make a simple device that allows you to drill square holes in wooden blanks according to the following recommendations.

  • To begin with, using a sheet of plywood or a wooden board of small thickness, you need to make the Reuleaux triangle itself, the geometric parameters of which should correspond to the diameter of the Watts drill used.
  • The drill must be rigidly fixed on the surface of the manufactured triangle.
  • In order for the Reuleaux triangle and the drill attached to it to move along the required trajectory, it is necessary to make a wooden guide frame. In the inner part of the frame, a square should be cut with geometric parameters that fully correspond to the dimensions of the hole that you are going to drill.
  • The frame is fixed on the drill with the help of a special bar, while the center of the Reuleaux triangle placed in the guide frame must coincide with the axis of rotation of the chuck of the power tool.
  • In order to impart a torque to the drill for making a square hole, but at the same time not to create restrictions for the movement of the tool in the transverse direction, the shank is connected to the drill chuck by means of a transmission mechanism operating on the principle of a propeller shaft of a truck.
  • A wooden workpiece, in which it is necessary to drill a square hole, should be securely fixed, while positioning it so that the center of the future hole strictly coincides with the axis of rotation of the drill used for processing.

Square Hole Drilling Fixture Parts Drawing

Table 1. Dimensions of guide bushings

Table 2. Drill sizes (click to enlarge)

Having assembled such a simple device, having securely fixed all the elements of its structure and the workpiece to be processed, you can turn on the electric drill and start the drilling process.

As mentioned above, a square hole drilled with such a device will have absolutely even and parallel sides, but its corner sections will be slightly rounded. Solving the problem with rounded corners is easy: you can modify them with a regular file.

It should be borne in mind that the above-described device, which is not characterized by high rigidity, is used to drill square holes in wood blanks of small thickness.

Watt’s drill and a square hole made with it in a metal workpiece