Even today, lathes play a huge role in the production of certain parts. All components and all equipment on any machines change over time, as they are subject to wear.
All these pieces of equipment must be of high quality and durable, since the quality finished products depends entirely on the quality of the installed parts. So is the lathe chuck. It is without this element that the machine becomes useless. Below we will analyze everything related to this element of the lathe. Let's start by finding out what this part is.
The cartridge is one of the main elements turning equipment. It is due to this that the future workpiece is fastened (installed). It is attached to the headstock with the gearbox. The chuck mechanism consists of a cam device.
It is the cams, under the influence of mechanical force, that tightly fix various workpieces having different diameters and sizes. Due to its massiveness and tight fastening on the machine, the chuck carries out accurate movement of the workpiece and does not allow the workpiece to move during operation, and also does not allow deformation. The chuck also rotates the workpiece, which makes processing easy.
Purpose
It is this part of the machine that has the most important mission in any workpiece processing. Due to the cam mechanism, which is located inside the chuck itself, the workpiece is clamped and centered. This happens due to the simultaneous narrowing of the cams around the plane of the workpiece. After clamping the workpiece, the workpiece is clamped with a quill located on the tailstock. When these actions are completed, the machine starts and the part rotates, which can be processed.
Tip: You need to know that before starting the equipment, after replacing the lathe chuck, you should set the rotation speed to low. This is done in order to check the values of the axial and radial runout of the jaw chuck operating at idle speed.
Variety
Nowadays, lathe chucks are distinguished by the presence fastening elements(cams). There are only three of these types:
Double cam
Such cartridges are capable of securing complex, asymmetrical and shaped parts. In such cartridges it is possible to secure surfaces that are not subject to treatment. They are used in small production, as well as in serial production.
Three cam
This type of equipment is the most common and is used in all work. Allows you to process round and hexagonal parts. This type of chuck uses three different jaws. Regardless of this, the workpiece is centered together with the clamping of all three cams.
Four cam
This type is used for processing rectangular workpieces. Here, for each cam, there is a separate mechanical unit, which makes all cams independent.
But the types of cartridges do not end with three types. They are also divided according to the mechanism for fixing the workpiece:
Collet
They consist of a sleeve with slots in which the petals are located (various modifications include from 3 to 6 petals). These petals act as cams.
Wedge
This type of equipment is used mainly on machines with numerical control. Fastening workpieces are produced using 3 cams, which are located on a flat spindle.
Lever
These cartridges contain sliders, with the help of which the cams move by lever force. This type is used for small-scale production, as well as for processing a single workpiece.
Membrane view
In this case, a pneumatic drive is used, with the help of which the membrane is compressed. This type is used only for fine processing, to remove a thin layer of chips.
Drilling
Such cartridges are similar in principle to cartridges for hand drills. When the nut is tightened with a special wrench, the cams are smoothly squeezed out. Due to this action, the part or tool is clamped.
Thermal cartridge
This type of device is very inconvenient to use. This is due to the fact that when attaching the workpiece, thermal heating of the chuck itself is performed, and the same actions are performed when removing the tool.
Hydraulic chuck
The principle of operation is similar to that of a thermal cartridge. The part is clamped by a liquid that compresses the cams under pressure. Due to the liquid contents in the cartridge, additional damping of vibrations that occur during operation is performed.
Tip: Before choosing a lathe chuck woodworking or for metal, it is necessary to decide on the type of processing, material and molding of parts. You should also remember that get additional accessories to the cartridge will not be superfluous.
Design
Let's look at the structural elements that make up the lathe chuck itself:
Key
Used to carry out clamping actions.
Spring
Allows you to use the key to perform certain actions to clamp the part and vice versa.
Sleeve
Produces free passage of the key.
Stopper
Prevents the part from unscrewing while the machine is running.
Gear
Transmits rotational motion to the spiral disk.
Flange
The part on which the entire structure is fixed.
Spiral disc
Due to the rotational movement of the gear, this disk drives the cams.
Reverse cam
Used for clamping the workpiece from the inside.
Cam straight
Used for clamping the workpiece from the outside.
Frame
An element of a part on which the cam mechanism is located.
Overhead cams
For clamping long and short parts with large diameters.
Each of the parts of the entire mechanism performs a specific function and is not superfluous.
Assembly according to drawings
The jaw chuck for turning equipment is assembled according to diagrams that can be downloaded from the Internet and printed on a printer. As a rule, factory cartridges cost a lot of money and therefore many have learned do such details homemade. Their design is simple, but quite understandable. Before you begin assembling this fixture, you must fully understand the entire mechanism of the chuck and cam mechanism. If it is not possible to make such elements yourself, then they can be ordered from any turner. It won't cost much.
Assembly begins with a flange on which all the necessary holes for fastenings are located. Following this, all the parts of the mechanism are gradually installed, which are completed by covering the body and bolting everything cartridge
Installation
Installation is carried out as follows and in strict sequence:
Installation of the mandrel
First of all, this part is installed to ensure complete fitting of the cartridge.
Installing the chuck itself on the spindle
Using a frame, it is put on the spindle and secured with bolts.
Consolidation
Attached cartridge onto the spindle with bolts. In this case, a simple open-end wrench will be a good helper.
Securing the workpiece
After installing the chuck, a part, workpiece or tool is fixed into it.
Releasing the cartridge
After all work, the mandrel is removed.
Tip: After replacing the jaw chuck, you need to check the operation of the machine. Axial runout and cones seat should not be higher than three microns.
It is important to know! This device must be disassembled frequently to lubricate and clean the cam mechanism! If the cartridge is in a removable state, then it must be prepared for storage. To do this, the cams are brought to the center, this ensures the safety of centering, and the hole in the center must be plugged with a clean rag or other material. This will prevent dust from getting onto the walls of the hole.
Video reviews
Video review of installation on the machine:
Video review, disassembly, cleaning, polishing:
Video review of a wood lathe chuck:
Video review of a homemade lathe chuck made of wood (cheap option):
One of the most common devices for processing metal workpieces is lathe. It can be used to make elements such as bushings, couplings, bolts, nuts, flanges and others. The equipment can be purchased ready-made in specialized stores, but it is possible to make a homemade metal lathe at home.
Features of the machines
There are many types of lathes for metal processing. Each of them has its own design features, on which their functionality depends. In addition, each type has the ability to perform additional operations, such as milling or drilling.
Regardless of the type of unit, their design may consist of the following components:
Depending on the type and model of the device, it can be equipped with additional attachments that will increase the functionality of the equipment.
Types of universal devices
Modern manufacturers offer users an extensive range of lathes. Among the most popular, the following types can be distinguished: turning-screw-cutting, turning-milling, turning-carousel, turning-turret.
Screw cutting machine
A special feature of this type of equipment is the presence of a tailstock quill stroke. Thanks to this, it is possible to equip it with a drilling chuck. This allows the machine to be used not only for turning operations, but also for turning workpieces with different profiles, leveling, making grooves and recesses in workpieces, cutting sizes to the required specifications, and drilling holes. For this, dies, cutters or taps can be used.
By using screw-cutting turning units, you can work with workpieces made of ferrous or non-ferrous metals. This type of device is most often used in tool production, instrument making or watchmaking.
If the choice fell on a screw lathe, it is recommended to take into account the following properties:
Milling device
Using this type of equipment, you can turn workpieces not only from ferrous and non-ferrous metals, but also from plastic and wood. The design of the device combines two types of machines (milling and turning).
A universal turning and milling machine can be used to perform such types of operations as continuous turning, thread cutting, chamfering, fillet cutting, cutting straight and curved grooves, and drilling holes. This became possible thanks to the presence of a milling part located in vertical plane beds. Such machines are often installed in school workshops.
Popularity turning and milling equipment due to the presence of its inherent advantages:
- Availability. The combination of two types of machines leads to cost savings.
- Compact size. It can be installed in a workshop with a small area.
- Possibility of mounting a variety of additional elements(cutter, drill, tap, reamer, milling cutter, chisel).
When choosing this type of equipment, it is necessary to take into account the following characteristics:
- distance between centers;
- workpiece size;
- diameter of crosscut and end mills.
The presence of these qualities determines the popularity of turning and milling equipment among users.
Carousel machine
Machines of this type are mainly used for processing large diameter(more than 2000 mm) and sizes in large enterprises.
Revolving unit
The main purpose of this type of device is to process workpieces made from calibrated rods. The peculiarity of the machines is that the cutting mechanism is mounted on a rotating drum.
Machine tools with numerical software
When working with this type of machine, minimal operator participation is required. It is also worth noting the ability to perform all types of operations with high accuracy.
Each of the above types of metal lathes has design features and purpose.
Self-production
If we talk about what you can make from a drill with your own hands, you should pay attention to a lathe, which you can make at home. This will not only help save money, but will also make it possible to perform a fairly large list of operations with different materials.
In order to make a metal lathe with your own hands, drawings of which can be found in specialized literature, you must first decide on the bed. It is considered one of the most significant pieces of equipment. It is on the bed that the turning attachment for the drill is mounted.
To make the frame, you can use a slab made of a material such as wood, up to 21 mm thick. The drill is fixed by the neck of its body, on which the auxiliary handle will subsequently be mounted.
In order to be able to saw materials such as plywood or hardboard, you need to install a drill chuck on the frame circular saw, the diameter of which does not exceed 2 mm. To ensure ease of operation of the machine, you can also mount an additional handle.
It is possible to replace the disk with a flat cutter. Thanks to this, the operator will be able to make grooves of shallow depth.
Now you can start making the stop, which is designed to serve as a tailstock. Thus, a homemade support for a lathe can be made with your own hands from two wooden blocks and one adjustment screw with a sharpened tip. This will make it possible to use the machine for processing small wooden workpieces.
If we talk about how to make a lathe from a drill, you should take into account that there are several options for devices that you can make yourself, the main thing is to have a ready-made template.
The caliper tends to wear out during operation of the machine. At the same time, the possibility of backlash cannot be excluded, which will have a negative impact on the quality of the operation performed. To avoid this situation, it is recommended to periodically adjust and tune the caliper.
A woodworking joinery machine has a frame. To make it, you can use beams or channels made of metal. Their thickness and dimensions are directly dependent on the load with which the equipment will be operated.
Shafts with guides located longitudinally are mounted on the beams. To attach them you can use welding machine, bolts or screwdriver.
The headstock can be made of a hydraulic cylinder, into the cavity of which two bearings are mounted. The thickness of the cylinder walls can vary from 5 mm or more. The hydraulic cylinder cavity is filled with a special lubricating fluid. Then the electric drive is installed.
The electric motor is responsible for the movement of the cutting part of the machine. Engine power has a direct relationship to the power of the device. When choosing it, it is necessary to take into account the size of the workpieces, which will be processed on the wall:
- to work with small workpieces, you can use a drive with a power of no more than 1 kW;
- if it is necessary to process large-sized workpieces, it is necessary to choose a motor whose power ranges from 1.5 to 2.5 kW.
A manual machine for processing metal or wood should be assembled taking into account the fact that all its components must be insulated. This will ensure operator safety when working with the machine, as well as structural strength.
Possible cutting mechanism options
The machine mechanism must be equipped with a cutting part. There are several variants of this node. Among the most reliable are the following:
The correct choice of equipment will provide the ability to perform an extensive list of operations when processing workpieces, increase the accuracy of the work, and also reduce the time it takes to complete it. A self-production a lathe for metal processing will help reduce the funds required to purchase ready-made equipment.
The accuracy and quality of processing largely depends on the installed chuck. The chuck secures a workpiece of piece or rod type and transmits the main cutting movement.
Machining at high cutting speeds requires the chuck to have high centering accuracy and reliable workpiece clamping.
Variety
The cartridges differ in design depending on their functional and technological purpose.
Lathe chucks are classified according to several criteria:
- Method of attachment to the machine: on the spindle flange, using an adapter flange, directly on the machine spindle.
- Jaw installation: independent movement, mounted directly on the spindle flange.
- Principle of workpiece securing: manual, mechanized (with hydraulic or pneumatic drive).
The principle of manual workpiece clamping
The use of a mechanized drive reduces the amount of auxiliary time spent on installing and securing the workpiece. The drive ensures precise positioning of the workpiece and centering during installation; this mechanism helps to increase processing accuracy.
Lathe chucks have different numbers of jaws. They can be 2, 3 and 4 cam. The cams are in direct contact with the workpiece during operation and hold it in one position. There are direct and reverse.
The tree (blank) is fixed by outer surface or a hole for parts in the form of bodies of rotation; prismatic parts are attached to the outer edges.
The cartridge is a complex technological product of a prefabricated design. In the manufacture of assembly units we use various materials. The body is made of gray cast iron grade SCh 30. The material for the parts is tool steel with high tensile strength and heat treatment. Roughness on working surfaces is not higher than 1.6.
Classification
Depending on the design, lathe chucks are:
- lever;
- self-centering;
- wedge;
- collet;
- membrane
Lever view
Perhaps the most popular design. The action of the mechanism is based on the movement of cams and clamps due to the mobility of a two-arm lever. The presence of a hydraulic drive allows you to optimize the design.
The main characteristics of the device include the number of clamps for securing the cam and the ability to move along the working disk. Setting up such a cartridge is quite difficult, especially with non-standard processing.
Changeover occurs according to two schemes:
- Independent adjustment of the cams is a labor-intensive operation and is not performed for every design type of chuck.
- Synchronous movement of cams with a key.
To carry out adjustment, a special key is installed in the groove for adjusting the hydraulic drive.
When working with a device of this type, there is a slight play of the part when rotating. For this reason lever designs more often used for roughing.
Self-centering view
The workpiece is centered in the chuck due to the simultaneous movement of the jaws, which is typical for a three-jaw self-centering chuck. Synchronous movement of all cams is ensured by the rotation of the disk, at the end of which grooves are made in an Archimedes spiral.
A bevel gear is cut on the opposite side of the disk. It engages with three small tips. When the key is turned, a small geared bevel gear meshes with the disk is rotated.
The disk begins to rotate and moves the cams inserted into the grooves of the spiral. Changing the direction of rotation brings the cams together or apart from the center. The bringing together or spreading of the cams is accompanied by clamping or squeezing the workpiece.
In power-driven chucks, the clamping force is provided by a hydraulic cylinder or pneumatic cylinder mounted on the rear side of the spindle. The cylinder rod is connected by means of a rod to the mechanism for moving the cams in the chuck. The rod passes through the central hole in the spindle. Moving the piston to one side or the other means that the workpiece is clamped or released.
Wedge view
The wedge design appeared after the improvement of the lever chuck.
The accuracy of movement of each cam was ensured after installing separate mechanical or pneumatic drives, which made it possible to use the device in precision operations.
The wedge chuck has an undeniable advantage over other designs. It has the function of shifting the workpiece axis from the central axis of the machine. The presence of eccentricity expands the machine’s capabilities for processing parts of complex configurations.
Characteristic features when working with wedge chucks:
- Difficulties in setting up for surgery.
- High installation accuracy with a low percentage of error.
- The evenly distributed load from the clamping force by each jaw increases the reliability of securing the workpiece.
A lathe with a CNC device needs quick readjustment. In such machines, clamping modules are installed with the ability to connect to the control system.
The material from which wedge chucks are made must meet high quality standards. The performance characteristics of the chuck must not be allowed to change during high speed machining.
Collet type
Helps you quickly and reliably fasten a cylindrical part on a lathe collet. During the first installation, difficulties may arise; a specialist should study the instructions, as well as the technical data sheet of the product.
The collet, which is the main structural element, is a bushing with longitudinal axial slots. Due to the slots, elastic clamping petals are formed. They serve as cams when clamping the workpiece. Their number varies from 3 to 6 in accordance with the diameter of the sleeve. The collet is placed in a housing with a clamping nut.
The workpiece installed in the sleeve is evenly compressed by the petals due to the pressure of the nut on the cone, which creates a compressive force. The workpiece receives rigid fixation, and there is almost no radial runout.
The collet-type chuck is designed for a long period of operation, and the number of fastenings and removals is not regulated. The master needs to develop a principle of operation on the machine, with the help of which the coefficient useful action will be optimal. Modern units are easy to customize; many workshops offer installation services for such equipment.
Membrane view
Membrane-type lathe chucks are characterized by high accuracy of centering and securing the workpiece.
A membrane made of elastic material is located on the flange of the mechanism. Clamping jaws with replaceable jaws are installed on it. The number of cams varies from 3 to 8.
When securing the workpiece, the pneumatic drive is turned on.
Under pressure, the membrane bends, the jaws diverge by 0.1–0.2 mm. The workpiece is inserted into the chuck until it stops and the drive is turned off. Under the action of elastic forces, the membrane tends to return to its original position. The jaws compress the workpiece.
Such a process takes a small amount of time, but the master requires scrupulousness, attentiveness and caution. The production process should not be taken lightly. Unit parts easily fail under pressure.
The membrane, made of spring steel, firmly holds the workpiece during processing. As the number of cams increases, the centering accuracy increases.
Membrane chucks are used for finishing operations with low cutting forces. The specifics of the work are not known to every master; it is necessary to study the regulatory framework, as well as the recommendations of professionals.
How to choose a part
The optimal chuck model for the machine is selected based on a comprehensive methodology. First of all, the technical data of the machine and the operations performed are taken into account. Based on this, the following parameters are analyzed.
Working diameter – experts pay attention to the outer diameter of the device and the size available for installation on such equipment. The fit size of the groove and the location of the fasteners are important.
Design - the method of securing the workpiece, the location and number of cams are important.
Parameters of the workpiece - you need to know the maximum and minimum diameter of the shaft and hole of the future workpiece, weight, length, configuration. These factors influence the method of fastening - direct or reverse cams.
The size of the hole in the hollow spindle for installing a rod workpiece. As well as the rotation speed range.
The operating conditions of the lathe chuck require placement in a closed room, where the negative impact of natural factors and aggressive environments that can cause corrosion is excluded.
Scroll chuck is an integral part of the lathe and without it machining is impossible.
The quality and performance of any equipment depends directly on the condition of its equipment. It is especially important to accurately, quickly and reliably secure workpieces on CNC machines and machines that operate as part of the GPS. To reduce the time required to position the workpiece on the machine, as well as to increase the reliability and accuracy of its fastening, chucks for lathes are widely used.
Features of the lathe chuck
A lathe chuck is an integral part of the equipment complex when carrying out turning operations. This structural part is intended for securing piece workpieces and bar material on screw-cutting lathes, grinders, turret and lathes, as well as metalworking equipment. With a lathe chuck you can clamp workpieces of a wide variety of sizes. The workpieces are attached to the inner plane of its hole, the outer surface or the outer surface for the shaft.
Lathe chucks with mechanized drives make it possible to reduce the auxiliary time required to install a workpiece on equipment and remove it after processing, thereby increasing labor productivity. On the other hand, these products increase processing accuracy, as they ensure coordination of workpieces relative to the working parts of the lathe and their reliable fastening, which eliminates deformation or displacement during processing.
Some of the world's most famous manufacturers of wood lathe chucks in Europe are Rohm (Germany), Bison-bial (Poland), as well as some domestic factories of technical equipment, tools and machine components. These products are quite expensive, but today it is simply impossible to imagine production without the use of lathe chucks.
Operating principle of lathe chuck
The lathe chuck should be used indoors and in the absence of aggressive substances that cause corrosion. Before starting work, the tightening bolts are tightened to the maximum with a wrench, then the lathe chuck is secured on the machine, all bolts are tightened with nuts and the lathe is started. It must be taken into account that low speeds are set to begin with to check the values of the end and radial runout of the lathe chuck at idle speed.
For fastening products on lathes, two- and three-jaw chucks are widely used, less often - four-jaw chucks. To fasten and hold parts, the lathe chuck contains cams, the number of which varies from 2 to 6. In this case, lathe chucks come with independent movement of the cams and with direct attachment of the cams to the flange end of the spindle. Depending on the method of fastening the lathe chuck to the machine, the following types of fastening are distinguished: on the flanged end of the spindle, through the adapter flange, directly on the lathe spindle itself.
Centering the workpiece in the chucks is achieved by simultaneously moving the clamping jaws in the radial direction. The cams of the lathe chuck move simultaneously with the help of a disk, which has grooves in the form of an Archimedean spiral on one side and a bevel gear, which is associated with three others, on the other. The key sets one wheel in motion, at the same time the disk also turns and moves all the cams evenly. The direction of rotation of the disk will determine whether the jaws approach the center of the chuck (the workpiece is clamped) or move away from it (the workpiece is released).
The clamping force in power chucks is generated by a hydraulic or pneumatic cylinder located at the rear end of the spindle. Through the central hole of the spindle, the cylinder is connected by a rod to the chuck mechanism, which moves the cams that clamp the installed workpiece into the chuck.
Compressed air or liquid enters the rotating cylinder during processing using special device called a coupling. As a rule, the movement of the cams from a mechanized drive reaches 5-10 millimeters, so the design of the lathe chuck in any case allows you to quickly readjust the product when moving from processing between batches of workpieces.
To increase the accuracy of workpiece fastening when performing finishing machining, it is customary to use overhead non-hardened jaws, which are bored on a machine to fit certain dimensions of the workpiece mounting bases. For this purpose, the main cams clamp a short mandrel to select gaps in all mates, and after that the working surfaces of the overhead cam are bored to the largest diameter base surface details.
The design of non-hardened cams and their fastening using mating type dovetail allows you to install overhead jaws with an accuracy of 0.02 millimeters and avoid their next boring.
For quick changeover between workpiece sizes, universal non-hardened jaws are required; this is achieved by rotating the round or hexagonal heads of the overhead jaws, which are mounted on the main jaws and bored to the desired diameter, into a certain position. Large-diameter workpieces are fixed in such a chuck with the cam stages placed in reverse.
If there is a need to process two similar surfaces, it is customary to use non-hardened cams, the error in fastening the workpieces in which can be reduced to 0.03-0.05 millimeters. Workpieces such as shafts that are longer can be installed in a lathe chuck, which has a rear center pressure.
DIY lathe chuck
You have become acquainted with the structure and main types of lathe chucks, and now we present to your attention a version of a homemade lathe chuck for a wood lathe. The main working part of the cartridge is the elastic sleeve, which has a diameter of 6 millimeters. It is necessary to use two types of bushings - polyurethane and rubber, for which you can take trimmings of sealing harnesses.
The union nut must be made of brass or bronze. Steel can also be used for this purpose, but bronze nuts have less friction. You can make the patch from any material, you can even take duralumin. The body is machined from steel. There must be an internal hole or thread in its shank - this depends on the design of the shaft shank of the device on which the cartridge is to be installed.
The rubber bushing and housing are the most critical parts in the cartridge. Whether the drill clamped in the chuck will “hit” depends on how accurately they are made. To reduce the likelihood of drill “beating,” make both parts in a certain sequence. Machine the chuck body in one setup. This technique will ensure the alignment of the central hole and the bushing shank with a certain accuracy.
The chuck body will remain in the lathe spindle after machining. Insert the elastic sleeve blank inside the cartridge and lightly press it through the patch with the union nut. IN tailstock machine, insert a drill with a diameter of 1 millimeter and drill out the clamped bushing. Using this method, it is advisable to make several bushings in stock.
If you are unable to lock the shaft of the drilling device when clamping the drill, you need to make flats on the body of a homemade chuck for a lathe wrench so that the union nut can be tightened tightly. In a lathe chuck you can clamp drills that have a diameter of 0.8 to 1.2 millimeters. For drills of a different diameter, the holes in the nut and bushing must be made differently.
The main difference between this chuck lies in the fact that the elastic sleeve will clamp the entire shank of the drill, and in order to install a standard drill in the Verbovoy chuck, it is recommended to cut off its shank. Make the hole for the elastic sleeve not in the nut, but in the chuck body; it should be as close as possible to the clamping device of the machine spindle. This significantly increases the accuracy of drill centering during installation.
Now you know what lathe chucks are for and what function they perform when working on a lathe. In addition, it is not at all difficult to make a lathe chuck with your own hands. To do this, you must first of all decide on the environment in which the product will be used and strictly follow our instructions.
