Collet chuck: device, design, operating principle and clamping action. Collet chucks DIY collet chuck at home

A collet chuck is a special device used for clamping a tool when performing turning, milling, drilling and other operations related to the processing of metal workpieces on a base. terms of reference(sequence of operations performed, processing technology, attached sketch of the product).

Types and principles of operation of chucks

Collet chucks are mainly used when processing cold-rolled rods or other metal products having an already treated surface.

Structurally, cartridges can be classified according to functionality:

with a fixed mechanism;
with retractable mechanism;
with retractable mechanism.

Each design has its own characteristics. The feeding type is made in the form of a steel bushing with 3 cuts forming petals that have a springing effect.

Drawing No. 1 of the main spindle collet

Collets type F - clamping the main spindle are used to secure the workpiece.

Drawing No. 2 of the counter-spindle collet

Collets type LN - counter spindle are produced elongated, size E depends on the standard size.

Drawing No. 3 collet type R

Type R – are pull-type collets.

Drawing No. 4 collet type T

Type T - clamping.

Drawing No. 5 collet BF

BF type feed collet - designed for bar feeding.

When installed on the machine, the feed collet is threaded onto the pipe with the help of which it is fed into work area. It is necessary to take into account the design feature - the size and shape of the collet, which mandatory must correspond to the profile of the bar being processed.

In preparation for processing, the rod moves through the petals, which due to design features hold the workpiece tightly. During processing, when feeding the workpiece, the adhesion force between the petals and the product increases due to rotation. The principle of operation of the clamping elements is based on strengthening the adhesion of the petals to the workpiece during rotation of the working mechanism. Bushings with 3 petals are used for processing products up to 3 mm, four – up to 80 mm, six – over 80 mm. Typically, collets have an angle at the apex of the cone equal to 30º.

When processing thin rods, collets equipped with springs are used to increase the clamping force of the jaws. When increasing the diameter of the workpiece being processed, designs are used that are equipped with special inserts selected according to the dimensions of the product. Collet clamps are also used when machining with a drill, cutter or tap. The sleeve is fixed in the cartridge using a nut, and cutting tool directly in the collet. When fixed with a nut, the internal volume of the hole where the workpiece is installed is reduced, thereby increasing the force holding the rod stationary.

Cartridges of this design also have their drawbacks. First of all, the requirement that the shanks of the tool used must match the characteristics of the collets used. At enterprises, the most widely used collets are the ER type, which comprise greatest number in the total volume of tools used.

When executing complex work for the manufacture of products, various collets are used, indicating all sizes and technologies for performing work operations, but often you have to combine equipment or make the necessary collet chuck with the required characteristics with your own hands.

Video review of the lathe collet chuck

How to make your own collet chuck

When making it yourself various products Situations arise when the available equipment does not allow the necessary operations to be performed. It is required to produce a collet chuck that meets the requirements, with the product being manufactured according to the developed sketch.

All work must begin with the preparation of a sketch with the elaboration of all the necessary details. The sketch of the chuck allows you to take into account all the features when making the necessary equipment and clamping mechanism with your own hands.

When making collets with your own hands, you need to consider several features:

the internal diameter of the collet is equal to or less than the minimum diameter of the part;
in a collet, an increase in the internal diameter is possible due to the expansion of the petals;
to increase the production of adjustable collets after setting and raising quality characteristics additional grinding of the conical and guide parts of the collet is necessary;
it must be taken into account that during long work The elasticity of the collet petals is lost, which can result in breakage.

A collet chuck is a type of lathe chuck. They hold the part while it is processed at high speed. There are several types for different forms details, types of processing and purpose. A collet chuck, unlike quick-clamping chucks (QCLs), does not require additional accessories: studs, screws or stoppers. Therefore, its second name is self-clamping. It's simple and reliable device has become widespread in equipping lathes. The most common type of collet is ER.

Types of chucks

Lathes, drilling and milling machines for metal use chucks with mechanical or manual clamping with 2, 3 or 4 jaws. Self-centering 2-jaw machines are used in the manufacture of shaped castings. In 3-jaws, hexagonal and round blanks with a Morse taper are attached. And when processing asymmetrical, rectangular or rods, 4-jaw sets are more convenient.

All clamps are divided into the following categories:

lever;
collet;
drilling (quick-clamping, BZP);
wedge;
hydraulic chucks;
membrane;
thermal cartridges;
3-jaw;
4-jaw.

Self-clamping drill chuck is used on universal or special lathes. Their design allows for a stronger transfer of clamping force with a torque significantly lower than spiral chucks. The structure is made of hardened steel and the set of cams is made of the same metal.

The delivery set includes a set of mounting bolts and cams. Often the cartridges that come with a drill or milling machine, they break quite quickly, as they are made of low-quality metal. A qualified turner can make a new one with his own hands.

Working principle of the collet chuck

Chucks with a set of replaceable collets are used for fastening axial workpieces and cutters on milling, turning, drilling machines, computer numerical control (CNC) equipment. There are many sizes and types of collet chucks that all work on the same principle. The self-clamping nut applies pressure to the end of the collet, which moves into the conical opening; its diameter decreases due to compression, firmly holding the tail end of the Morse cutter. To remove the cutter or part, the nut is screwed together, the pressure is reduced and the collet is released.

The advantage of collet chucks over others is the small radial runout of the workpiece installed in such clamping device. Fixed in a self-clamping chuck, the part is perfectly centered. Unlike quick-release drills (QCLs) used in drills, self-clamping drills operate without keys, which are often lost.

Typically, such fasteners are used for processing bushings, cylindrical parts with a Morse shank, and rods. They are very convenient for secondary fastening of already processed parts. If the profile of the part does not match the shape of the cartridge inlet, replaceable cartridges from the kit are used.

Collet chuck design

The chuck consists of a clamping nut and a set of collets. Available with retractable, retractable or fixed collet. According to their purpose, collets can be clamping or feeding.

The feed collet is a hardened steel sleeve with 3 cuts that form a kind of petals with ends directed towards the center and springy. The opening of the feed collet should be such that the workpiece is clamped tightly. The feed collet is screwed onto a rotating feed rod, which feeds the workpiece using a hydromechanical or cam mechanism. When installing the workpiece into the chuck, its Morse end moves between the petals, spreading them apart. Under the influence of elasticity, the petals are pressed tightly against the workpiece. Adhesion increases during processing due to frictional forces.

A solid collet is a sleeve with petals that spring back when impacted. To work parts with a diameter of less than 3 mm, three-lobe collets are used, from 3 to 80 mm - four-lobe collets, and more than 80 mm - six-lobe collets. The grip is increased by reducing the clearance of the slots as the collet is pulled into the chuck.

Split collet - used for fastening parts of the smallest diameter. The jaws of such a cartridge are moved apart using springs. Split collets can be equipped with replacement inserts; their type and dimensions depend on the characteristics of the workpiece.

Collet chucks also hold metalworking tools (drills, taps, cutters) with a small diameter Morse shank. The cutter is secured with a replaceable collet, additionally reinforced with a nut. When screwing the nut, the collet is recessed inside, and being elastic, it firmly clamps the Morse shank. The disadvantage of this type of chuck is that each cutter diameter requires its own collet.

In longitudinal turning machines, a self-clamping chuck is used to secure the mini-workpiece being processed. The design of such collets is somewhat different from conventional ones. Together with them, conventional tools for clamping a Morse taper can be used to secure the workpiece.

How to choose a collet chuck

The first condition when choosing a self-clamping chuck is attachment to the spindle. The clamp can be installed directly on the spindle, through an adapter, or screwed onto a thread.

Flange size: diameter of the flange for connection or Morse taper parameters. Without knowing the parameters of the end of the flange, you will not be able to select a cartridge.

Number of cams: a set can have two, four, six. The price of the product depends on the quantity, shape and metal. Depending on the type of work, you can purchase fasteners made of hard or soft metal alloy.

How to make your own cartridge

For working on wood, soft metals and plastics, homemade printed circuit boards A mini-drill of low power, made by yourself, is suitable. The easiest way is to equip it with a ready-made mini-self-clamping mount made from a pen or pencil. But if you don’t have any at hand, it’s not at all difficult to make a mini-collet with your own hands. Required: soldering iron, 1 mm thick steel wire, solder.

Work progress:

a spiral is rolled from the wire with a diameter equal to the diameter of the electric motor shaft and the drill with which to work;
the spiral is soldered, high quality connections are ensured by soldering flux or KFET;
the spiral is put on the shaft and the mini-collet is ready.

Video about how a qualified metal turner made a self-clamping chuck with his own hands.

The problem of consumption or lack of collet cartridges is especially familiar to jewelers. Specialists involved in the manufacture of printed circuit boards also face this problem.

Collet chucks can be created independently from available materials. However, there are some nuances that will be covered in detail in the article below.

It should immediately be noted that manufactured on a quick fix the collet will not be dismountable. That is, strictly speaking, removing one drill from it and inserting another will not work. For this reason, the manufacturing method is more suitable for those who need to create a large number of identical holes.

So, to create a homemade collet chuck we will need:

drill;
blank;
steel wire;
soldering flux;
hoop.

Initially, you should wind the steel wire around the blank in the form of a rigid spring (the half rings come as close to each other as possible). Next, the resulting structure must be thoroughly soldered.

It should be remembered that the diameter of the drill must coincide with the diameter of the motor shaft, which will rotate the drill in the future.

Today, anyone can easily purchase a special cam for any type of drill. This can be done both in construction boutiques that offer equipment for sale, and on the Internet (at auctions such as Ebay or Amazon).

Such a cam will be screwed onto the threaded connection of the shaft of the rotating device. The more tightly the cam is twisted, the more firmly it compresses the drill placed in it.

The price of such a device does not exceed sixty rubles. Purchasing a cam will forever save you from searching for suitable collets for using various drills.

Of course, it is better to purchase a cam made of high-carbon, durable steel. To tighten it, it is recommended to use a special wrench, which is included in the kit.

Quite by accident I noticed that the length and inner size plastic stopper from glass bottle match the length and outer size of the electric motor from an inkjet printer, which has long been aspired to become a . On the first free evening, I disassembled the plug (it’s easier to have and use two - we break the body of one and take out the inner part, in the second, on the contrary, we save the outer part when disassembling) and adding everything with a front fastening washer, a “tulip” connector and wires, I got the following design:

Which I assembled into a single whole using two screws and three small self-tapping screws.

Adding to this a power supply wire and a specially purchased collet for attaching drills with a diameter of 0.7 to 1 mm. But the seller’s assurances did not come true; the drill collet did not fix a diameter of less than 1 mm.

However, the prospect of “bending” under the pressure of circumstances is not very attractive, and therefore, having strained my brain, I decided to try the following:

The diameter of the “nose” of the syringe on which the needle is installed is slightly smaller than the diameter of the electric motor shaft (2.5 versus 3.2 mm), but the problem can be corrected.

I took a 3 mm drill, increased the diameter, cut what was needed from the body and forcefully pressed it onto the shaft... and nothing happened. The needle did not fit in place, the alignment of the mounted element did not stand up to criticism.

Then I took drills of the following diameters - 2.6 mm, 2.8 mm, 3 mm, 3.1 mm and with their help enlarged the hole gradually and with inside housings.

I slightly modified the hole with a round needle file.

With a little effort, I put the adapter on the shaft and carried out external finishing.

He heated the medical needle over the fire and pulled it out from the installation site with pliers.

The diameter of the extracted needle, 0.7 mm, corresponded to the diameter of the drill being installed, but its shank entered the resulting hole only after applying quite sufficient force.

The next drill had a diameter of 0.8 mm; a needle with a corresponding diameter of 0.8 mm was also found for it (plastic blue), but for a drill with a diameter of 1 mm there was no suitable needle and the hole from the 0.8 mm needle had to be drilled out with the same drill. However, installing it using pliers also required some effort.

Video

There is no runout of the drill tip, the adhesion of the drill mandrel with the adapter on the shaft is sufficient even to easily drill 17 mm particle board and at the same time, the mandrel with the drill can be easily removed if you pry it off with a screwdriver. Well, why not an alternative to a collet clamp (I’m still silent about the lack of financial costs). In general, I came up with another application in amateur radio practice for medical syringes, and primarily those already used (I hope this is so) Babay from Barnaula.

Discuss the article HOMEMADE DRILL HOLDER

The main advantage that a self-assembled mini-drill differs from standard products is its compact size and the ability to obtain electrical equipment without significant expenditure of money, effort and time. Make one like this homemade instrument easily at home, since this does not require special skills or highly complex devices. To get a high-speed drill or other devices for making crafts, home handyman you just need to be “friendly” with pliers and be able to perform simple technical operations.

Instructions for making a drill

When making small things, decorative and other products, a compact drill, engraver and the like hand tool very convenient, so it remains indispensable in the home workshop. Using such equipment, you can drill and process products made of wood, plastic, textolite and other durable materials. You will also need a micro drill when drilling printed circuit boards.

To manufacture drilling equipment, select a suitable chuck and a body of suitable dimensions ( plastic container). To rotate the working surfaces, you need to select electric motor and a power supply, for which you can disassemble an old hair dryer or other electrical equipment.

To learn how to make a mini-drill, just read the following list of recommendations:

First you need to fix the cartridge on the shaft of the electric motor, for which you will need adhesive materials (“ cold welding"), which ensure the reliability of metal connections.
You will have to work very carefully, since the adhesive materials set quickly, which eliminates the possibility of eliminating errors and correcting the connection.
After fixing the cartridge, it is better to cover its surface with a special heat-resistant glue, which will ensure the density and strength of the connection.
On the case you need to make a hole in advance for the switch (preferably a push-button one).
The drill will be more functional with a reverse mechanism, which is implemented using a six-pin switch.
When connecting to power, you will need a 12 V power supply or a battery (2-3 pieces) of the same voltage.

Having assembled a mini-drill into a single structure from individual parts with your own hands, you can turn on the power and do test drilling.

Assembling the collet chuck

To secure drills in a drill, you will need a special collet or chuck in the form of an adapter with clamps for drilling tool. This mini drill chuck is attached directly to the electric motor shaft. Handmade collet clamp allows you to work with drills with a diameter of 0.7 to 3 mm. The more carefully and accurately this element is assembled, the more accurate the drilling will be.

It is important to choose the right cartridge, so if it is impossible to find suitable option better take it on self-production. No need for this lathe, because all you need to do is select a screw and a closed nut with an M8 thread. When assembling the cartridge, proceed in the following order:

Drill a 2mm hole in the screw head and nut.
Make axial cuts with a hacksaw.
Enlarge the holes with a 3.5 mm drill.
Grind the nut until it has a cone shape.

Having thus assembled a mini-chuck for a drill with your own hands, you can begin installing it on the drill. If necessary, select similar chucks for drills of any diameter.

DIY mini drill

Drills are used by modellers, home craftsmen and those who love making small parts or decorative elements. The presence of a flexible shaft in such a device allows you to work with the most small details and treat surfaces complex shapes(grinding, polishing, cutting, applying patterns). Assembling such a machine is as simple as making a drill with a mini-chuck for drills with a diameter of up to 3 mm. To do this you need to find main component- an 18 V electric motor, which can be used in a screwdriver or blender.

The procedure will be as follows:

Disassemble the blender by removing the top cover and cover, unscrewing the mounting bolts.
Remove the electrical circuit, power cable and the part located above the rotator from the housing.
Remove the tip on the electric motor shaft, remove dirt from the housing and shaft.
Select the cartridge according to the shaft size (the most accurate way to measure the diameter is with a caliper).
Secure the microcircuit and the on/off mechanism.

The assembled instrument can be connected using a cable to a regular outlet. Rechargeable batteries or regular batteries are also suitable as a power source, which will have to be replaced periodically.

Flexible shaft for Dremel or micro drill

Rotation can be transmitted to replaceable attachments using a device such as a flexible shaft made of durable twisted wire with a protective metal coating. For self-assembly This device will need a few simple things:

brass or copper tube;
bushings with metric thread M4 (2 pcs.);
metal shaft made of 5 mm electrode (M5 thread);
adapter for thread 0.75;
mini-chuck for quick fixation of the cutting tool;
metal clamp (M12 bolt with a hole along the axis);
protective coating at the connection point.

To assemble a flexible shaft, an electrode is placed in the tube and secured with bushings. On one of the bushings you need to attach an adapter with a cartridge, and on the other, install a clamping device for connection with the flexible part. After all these operations, the protection made of brass or copper is secured. Installed on the cartridge plastic handle on the clamp, which simplifies the work with the tool.

Dynamo from printer drive

You can make a micro-dynamo yourself if you disassemble a used printer. Such a portable device will be able to convert mechanical rotation into electrical energy, which arises under the influence of magnetic induction in a closed loop. This homemade product allows you to get a simple generator at home DC, which is useful for powering small electrical appliances, charging mobile phones, tablets and other equipment. A small dynamo can also be used to LED lighting, bicycle light with connection to a single-phase circuit.

Just like a bur or a do-it-yourself microdrill, a dynamo is assembled from improvised materials that can be found at home. An example kit looks like this:

electric motor;
belt drive;
non-slip handle;
base made of wood or other durable material;
capacitors with a capacity of 10000 μF (4 pcs.) and a diode (1 pc.);
wires, fasteners, metal corner.

The only condition for successful assembly of the dynamo is the selection of suitable sized and fully operational components. All the parts needed for this can be found in any home printer. Before assembling the dynamo, it is better to make a drawing in advance and get a clear idea of the location of each element.

The device is assembled in the following order:

Connect capacitors in parallel.
The phases are connected to the electric motor through a diode, and the zero is connected to the motor zero.
Secure the device to the base.
Install the gear with the handle.
Tension the drive belt.

When assembling the structure and connecting the contacts, polarity must be taken into account.

Micro motor at home

Compact electric motors are used by modellers and lovers of various small crafts with electric drive. Such a device is the most common DC electric motor with a brushless circuit. To make this device, a vibrating platform from a mobile phone is suitable, and as a shaft you can choose a thin drill (up to 0.29 mm), on which copper wire is wound in two layers.

The procedure for manufacturing an electric motor is as follows:

Coat the winding with epoxy.
Fix the electromagnet.
Attach fluoroplastic bushings to the electromagnet.
Install the entire structure under the winding.

To be fully ready, you need to mount the valves and make the connection using a five-input microchip.

A description of what can be made from a drill or an old printer will help you assemble quite complex devices at home that are needed by craftsmen, model makers and just lovers of crafts. Knowing how to make a collet clamp with your own hands or make an electric motor, you can save a lot, because all these products are made from used devices and parts. All costs are reduced only to the time allocated for assembly.