Kolovoroty: what is it and how to use it?

Drilling work is a necessary companion to any construction projects. For a long time, a drill has been used to obtain even holes, and various devices have been invented for ease of use. One of them is a brace - the simplest tool that looks like a bent handle in the shape of a bracket with a chuck for fixing the drill. The oldest drilling device is the prototype of a mechanical drill.

The name of the instrument comes from the ancient Slavic words "kolo", which means "circle" and "gate", translated into modern language - "rotate", describing the principle of the brace: rotation around an axis in a circle. An earth drill or an ice drill operates on the principle of a swing, which is used by fishermen when drilling holes for ice fishing. But, although in common parlance these tools are called a brace, in fact, only a drill can be called that.

The very first drills with a prototype of a brace were known in Ancient Egypt 3000 years BC. The instrument, close to modern outlines, was invented in the 15th century. Various craftsmen invented different types of braces, most of which never found practical application, as they turned out to be inconvenient and ineffective to use.

Like any instrument, the brace has its advantages and disadvantages. The main advantage of this device is its simplicity of design, due to which its reliability and durability is created.

The low rotation speed allows you to work very accurately and accurately, to obtain indentations of the required depth with millimeter accuracy and to change the drilling angle. It also makes it easier to work with very thin drills, which on high-speed models quickly break due to side vibration.

Another of the advantages of a brace is its price, which is much lower than the price of a drill and a power tool.

Against the background of these advantages, there are very few disadvantages, and they are insignificant:

• heavily outdated and low speed fixture;
• it is not always possible to change the chuck for fastening a workpiece with a non-standard shank - for this you need to have several tools with different types of clamps or have interchangeable clamping devices for a certain type of shank.

The simplest brace is a one-piece bent metal rod with a thread applied on one edge to make holes. In more complicated models, you can change the drill, since it is possible to attach the shank of the cutting part in the hole of the hollow tube from which the tool is made using a side screw. In improved models, the fixation of the working device is carried out using a chuck, a special shoe with an internal cavity of a square or rectangular cross-section, or a Morse taper.

The modern brace consists of:

• a mushroom-shaped push handle mounted on a special bearing to keep it stationary during operation;
• a crankshaft with a handle on a curved part for easy rotation;
• ratchets for better distribution of forces and the ability to work the rotor in places where it is impossible to make a full revolution of the shaft;
• chuck for fastening the cutting tool.

The chuck used to secure the cutting part can be a self-centering two-jaw or three-jaw, and sometimes a collet is installed. All of these clamps are suitable for round, square and hexagonal cylindrical shanks. The Morse taper mount is used to clamp taper shanks. It is important to remember that if a collet is used for clamping, then using cutting parts with a large shank diameter will not work. Also, different collet sizes are required for different shank diameters.

Rotors are available with non-replaceable heads and replaceable cartridges. For tools with replaceable heads, there is a special GOST - 25602-83.

The circle made by the rotary handle around its axis is called the overhang or swing. The diameter of this swing determines the size of the brace. Tools with a span of 25 cm are available, the most demanded by craftsmen, but you can also find a device with an overhang of 14.7 cm or 30 cm.

If the swing range does not allow making a full revolution, then the ratchet installed in front of the chuck will help. Having made a rotation as much as possible, the handle is returned to its original position and the movement is repeated over and over again, and the ratchet prevents the drill from making a reverse movement during the return movement of the handle. In the event that a reverse stroke of the tool is required, the ratchet has a direction-of-travel switch ring.

The principle of operation of the brace is simple: a drill tip is attached to the selected drilling point and fixed using a pressure head located in one straight line with the cutting part. After that, they begin to rotate the crankshaft around the formed axis, constantly pressing on the push handle. Due to the physical efforts of the working, the drill goes deeper into the work surface during drilling. The working speed depends on the shaft speed. During work, it is important to ensure that the axis of the bend is a continuation of the drilling direction, so that the drilled channel does not go to the side.

If it is necessary to obtain a through hole in a workpiece with a large thickness, it is better to drill from both sides, carefully marking the entry and exit of the drill. When drilling a part from one side, before finishing work, it is worth relieving the pressure on the handle to avoid delamination and breaking off the edges of the hole when the drill comes out. You can also put a board under the workpiece to get an even edge of the hole.

For safe work, it is important to use only high-quality, crack-free drills. If blunt and improperly sharpened drills are used, the surface of the hole is ragged. An improperly mounted drill will result in a different hole diameter due to the runout of the cutter.

When working with the tool, there are no problems with direct and reverse movement due to the simplicity of the design, it does not depend on the availability of power sources. Due to the low speed of movement, the device is convenient for precise work.

Initially, the brace was used for drilling only in wood, but in the course of technical progress, it became necessary to obtain even holes in metal and plastic products or parts made from other modern materials. Now, with the help of a slow-speed tool, you can drill metal or plastic, getting neat holes without chips or dents along the edge, which sometimes leads to the use of high-speed electric drills.Also, using a brace, you can get even large-diameter holes in products made of thin sheet steel without disturbing the shape of the workpiece.

Depending on the attachment used, the following work can be performed using the brace:

• surface drilling, for which drills of the required diameter are used;
• screwing and unscrewing screws, self-tapping screws or screws using bits of the desired configuration;
• cutting of internal threads using a tap;
• obtaining an external thread on small diameter parts using a die;
• making holes for a countersunk bolt (countersinking) or enlarging a hole in a part (countersinking);
• the use of locksmith heads complete with an adapter - cardan;
• lapping the valves to the seats in the car engine heads.

This is a list of the main functions of a modern brace, but with a certain approach, you can pick up a few more ideas for using this tool in everyday life in the absence of electricity.

Although the brace is the "progenitor" of the hand drill and the main function of these tools is the same, they differ significantly from each other.

Like a brace, a hand drill is a tool that is simple in design and use, and is quite reliable in operation.

The first difference between a brace and a drill is their appearance. If the rotor is a crankshaft with a handle-stop and a chuck for fixing the cutting part, then a hand drill consists of a gear train mounted on a transmission shaft with a chuck at the end, a handle for rotating the gear, a shoulder rest and a handle for additional tool support.

The next difference between the tools is the number of speeds. The rotor has only one rotation speed, depending on the efforts of the master, and a hand drill can be one-speed or two-speed (depending on the absence or presence of a two-stage multiplier). This device is a mechanical gearbox consisting of a set of gears arranged on different axes in one housing, it serves to switch the operating speed by changing the gear number of revolutions.

Despite the technological progress, simple and reliable tools will serve their owners for a long time, ensuring high-quality performance of the necessary work.

For information on how to drill a tree with a brace, see the next video.