Do-it-yourself tool for unscrewing the studs. Do-it-yourself eccentric stud driver. How to unscrew a stud from an aluminum part
Hello!
At the beginning of the year, we had a "season for replacing CV joints", "grenades" flew one after another. Me, relatives and friends.
All these old parts lay in scrap metal, waiting for their turn.
Making a do-it-yourself stud driver
For the manufacture of a stud driver, in addition to the CV joint and a standard set of tools, you will need electric welding.
I cut off everything superfluous from the tripoid, cut off the eccentric blank from the shank.
I made a slot in the body of the tripoid so that an eccentric was placed in it.
Sanded the blanks.
With the help of two nuts and a rod, I connected the eccentric to the body. Made a handle out of a broken wrench.
Stud driver test
First test. The bolt, strongly clamped in a vise, spins quite easily without additional leverage.
Cleaned everything up again. The handle from an old cord brush came in handy.
Such a tool should last a long time, because. the metal is good, and the teeth are additionally hardened.
And here is a purchased stud driver of a different design. The teeth on the eccentric crumpled on the very first pin. (not visible in the photo).
I will tell you about what else can be made from CV joints in my next works. Thanks to all!
In specialized car workshops, in production, in construction - wherever you often have to work with studs, a stud driver is used. Experienced craftsmen who know their business do not need to explain its purpose. And the name speaks for itself. However, many may not be clear about the design features of the tool, its appearance, how it works and how much it costs approximately.
Design features of the stud driver, the principle of operation
The most famous design of this tool consists of a body in which three rollers are located. Due to the complex inner surface of the housing, during rotation, the rollers firmly clamp the stud, ensuring its eversion even in difficult cases (fastening of automobile manifolds, muffler elements and other places where the thread of the studs “sticks” to the hole of the part into which they are screwed). On the reverse side, the body, as a rule, has a square hole for the standard size of ratchets (knobs), as well as a hexagonal shape of the outer surface, to hold it with a wrench.
In addition, there are designs whose fundamental structure is similar to the usual three-jaw (collet) chuck. The jaws of the chuck also provide a secure hold on the stud during rotation, which makes it possible to unscrew or tighten it with minimal effort. Such a tool is more versatile, since it is supposed to work with studs of different diameters. Some designs based on the principle of clamping with a rotary eccentric also have a certain versatility (the scope is expanded due to the fact that the same tool can be used with different fastener diameters).
Many designs have been invented by those who like to make equipment and auxiliary mechanisms with their own hands - starting with several nuts compressed together on the free thread of the stud, to relatively complex devices where wedges or eccentrics are used to fix the stud.
If the use is frequent, then it makes sense to purchase not one stud driver, but a set for different diameters of the studs. Rotation can be carried out both manually and with the help of various power tools - screwdrivers, pneumatic wrenches or drills. After the pin is safely unscrewed, the pin driver, turning in the opposite direction, is removed from it. In fairness, it should be noted that after using this device, the stud thread must be restored with a die (the thread turns out to be somewhat crushed), especially if the fastener is to be reused.
Benefits of using stud drivers
A fairly large number of people today face difficulties in dismantling threaded fasteners (studs or bolts). If we talk about a car service, this is most often associated with the repair of old cars, where some elements of the connection have not been unscrewed for decades. The advantages of using a special device are as follows:
- with its help, in the vast majority of cases, it is possible to unscrew the bolt with a broken head without damaging the thread in the part;
- the hairpin itself remains practically undamaged; after running with a die, it is suitable for reuse;
- minimum time spent on work;
- Made of high quality steel, the tool is strong and durable;
- in hard-to-reach places it is often more convenient to use a stud driver, rather than improvised means.
Simply put, the tool makes work easier and faster. It's no secret that a broken rusted bolt in the absence of special equipment can paralyze all car repair work. And an unsuccessfully turned out hairpin can cause the repair time to triple. Therefore, if the pin suddenly does not want to wriggle out of a place where its breakage can cause serious problems, it is better to use specially designed tools for this.
Price for stud drivers
For domestic use, a universal stud driver can be quite convenient, which allows you to work with different diameters of threaded parts. For car services or service stations, the most functional may be a special set, including up to a dozen heads of the most common diameters. Moreover, finding and buying a hairpin today is not difficult - these devices are sold both in regular stores and on various Internet sites. Prices are quite democratic - for a universal eccentric mechanism, this range is from 400 to 1000 rubles. Stud drivers with three rollers are sold from 300 to 600 rubles apiece, if we consider the most common sizes. Sets can be purchased from 1.5 to 8 thousand rubles, depending on the configuration, quality and manufacturer. In the case of professional use at the manufacturer, it is better not to save money, especially since the difference in price is not too big.
In the practice of repairing automotive equipment, it becomes necessary to screw in and out of studs - fasteners without turnkey surfaces. For these purposes, a special tool is used - a stud driver or a key for studs. Read about stud drivers, their types, work and choice in this article.
What is a hairpin?
A stud driver (key for studs) is a specialized tool for screwing in and out of threaded studs.
Stud - a fastener in the form of a rod with a thread at both ends. The stud is screwed into the product with one part, and the nut is screwed onto its second part. The design of the stud does not provide for special surfaces for thorns (such as heads for bolts or edges for nuts) or other tools, which greatly complicates the procedure for screwing in and out. As a result, it is necessary to use special tools, which are called stud wrenches or simply stud drivers.
For the correct purchase of a stud driver, it is necessary to understand the existing types of this tool, their features and advantages.
Types, design and principle of operation of the stud driver
The main problem of working with studs is to ensure a secure fixation of the cylindrical rod without damaging it and with the force necessary for screwing in or out. Several solutions to this problem have been proposed, and according to the method of clamping the studs, the stud drivers are divided into several types:
- roller;
- Eccentric;
- Collet (cam);
- With nut clamp and stop.
In this case, all types of tools can have the execution of one of two types:
- An independent tool that works without additional devices;
- Equipment for working with conventional wrenches, wrenches, ratchets and other devices.
The tool of the first type is convenient and easy to use, it is always ready for use, however, as a rule, it has a more complex design and high cost. The second type of tool may have hexagon wrenches or a standard size square (usually 1/4, 1/2 and 3/4 inch) for a knob, ratchet, etc. This tool is more versatile, compact and affordable.
Each of these tools has its own design features and principle of operation.
One of the most simple in design and reliable tools. In the general case, it is a cylindrical body, inside of which there are three cylindrical rollers, between which spacer inserts can be additionally installed. The inner surface of the housing has a complex profile (triangular with rounded edges and corners, with ovoid elements, etc.), so the rollers, rolling inside the housing, can approach and move away from its central axis.
The roller stud driver works simply. The tool is put on a hairpin and rotated with a key or a knob. When turning, the rollers roll over the stud and the inner surface of the body, which leads to jamming of the stud - now the force from the hand is transferred to it, which allows you to screw it in or out.
Wrenches for studs of this type are simple, reliable and convenient, but they have a significant drawback - each stud driver is made for a certain diameter of the stud. Only in this case the necessary pressing of the rollers to the stud and its jamming when turning is ensured. Therefore, to work with various studs, it is necessary to have a whole set of roller stud drivers.
This type of tool is also very simple, while it is more versatile than a roller tool. Structurally, this eccentric stud gun is very simple: it is based on a body with one or two holes for studs, on which there is a hinged eccentric - a metal disk with a corrugated rib and the ability to approach the holes. Also on the body is a knob or square for installing a knob, ratchet or other device.
The eccentric stud driver works simply: the tool is put on the stud, the disk is brought to the stud, and the entire tool is turned - when turning, the eccentric rests on the stud, jams it and allows you to transfer the force necessary for screwing in / out.
Today, two types of eccentric stud drivers are produced:
- Universal - with one or two holes, allowing you to use the tool to work with studs of various diameters;
- Under the size - with one hole for working with studs of the same diameter.
It should be noted that there are tools that combine the design features of eccentric and roller stud drivers. In such a tool, there are three small eccentrics covering the stud, when the tool is rotated, the eccentrics wedged the stud at three points, providing maximum pressure and transmission of great force.
This is a universal tool that has a device similar to the collet chuck of a drill and other tools. The basis of this type of stud driver is the body, inside which are movable cams. When the body is rotated, the cams converge towards the center, clamping the pin, and ensuring the transfer of force to it from the hand.
Collet stud drivers are the most versatile, as they allow you to work with studs of various diameters, even non-standard ones. However, the cams do not always provide the necessary degree of fixation of the tool on the stud, so this type of stud driver often cannot cope with fasteners. This is an inexpensive amateur tool that is practically not used in auto repair shops.
Stud driver with nut clamp and stop
This tool is quite simple in design, so it is often made in artisanal conditions. The basis of the stud driver is a body with handles, in the lower part of which there is a nut, and in the upper part there is a thread for screwing in the wrench. In the housing opposite the nut, a hole is drilled with a thread for a bolt or screw, with which the nut is fixed from turning.
This tool works simply. A nut of the required size is installed and fixed with a bolt in the body, the tool is screwed onto the stud with a nut, then a knob is screwed into the body, it abuts against the end of the stud and is wedged. Now the body is rotated counterclockwise, and the stud, fixed with a nut and a wrench, is turned out.
This tool is used, as it should be, only for turning out the studs. It, despite the simplicity of design, requires a large number of operations to work with one hairpin, so it is not always convenient. Today, stud wrenches of this or similar design are rarely used, they have been superseded by simpler and more convenient roller and eccentric stud drivers.
How to choose a stud driver
When choosing a stud driver, it is necessary to take into account the nature of the work to be performed by this tool, and their frequency.
For use in a garage where the studs only need to be removed from time to time, a universal eccentric stud driver is the best solution. Such a tool will allow you to work with studs of various sizes (it can be used to unscrew and screw in the studs of almost all engines - from two-stroke scooters to medium-duty trucks, you can also repair other units with studs), it is reliable and easy to operate, and has an affordable price. You can also purchase a collet stud driver, but it does not always provide the necessary degree of fixation and cannot work with large diameter studs.
For professional workshop applications, roller or eccentric stud driver sets are the best choice. The presence of a tool for a certain size of studs significantly improves the quality and speed of work, and the cost of it pays off in a short time. Although in this case it will not be superfluous to have a universal eccentric tool - with its help you can quickly perform simple work.
With the right selection of a stud driver, you will provide yourself with a reliable tool that will help you solve the most difficult problems in the maintenance and repair of vehicles.
Quick key.Participants of the NTTM of the Novokuibyshev Freight Motor Transport Enterprise of the Middle Volga Transport Administration introduced a high-speed universal key for screwing in the studs. Thanks to the use of interchangeable inserts with central threaded holes for different diameters of studs, it can be used for screwing studs of any size.
The key consists of a hollow body, a spring, a bolt, a stud, a conical thrust bearing and an insert. Before starting work, an insert with a thread corresponding to the size of the stud is inserted into the key body. When screwing by hand, a handle is put on the shutter shank, with a mechanical drive, the key is attached to the cartridge. During the rotation of the tool, the insert is screwed onto the stud and deepens it into the part. At the same time, under the action of a spring, the shutter, held in the lower extreme position by a finger, enters the horizontal part of the groove, providing automatic locking with the upper end of the stud.
Universal hairpin:
1 - housing, 2 - spring, 3 - shutter, 4 - pin, 5 - conical thrust bearing, 6 - insert.
When the key is reversed, the finger moves from the horizontal part of the groove to the vertical one and moves the thrust heel away from the end - the key is easily screwed from the stud installed in the part.
Blanket for concrete. Like a thick carpet measuring 400X1500X40 mm, it spreads on the surface of freshly laid concrete, warming it up and thereby accelerating setting, hardening and drying.
Portable building heating pads were proposed by the participants of the NTTM of the Kuibyshev Civil Engineering Institute named after A. I. Mikoyan. They have already found wide application at the construction sites of Kuibyshevgidrostroy, where they are used for active heat treatment of concrete and reinforced concrete structures up to 250 mm thick with one-sided heating and up to 500 mm with two-sided heating.
1, 5 - rubberized fabric, 2 - mesh heaters, 3 - glass wool, 4 - moisture glass wool.
In the section, the blanket is a multi-layered "pie". The role of "crusts" in it is performed by a rubberized fabric, which forms an outer moisture-proof shell. Immediately behind it are two layers of mesh heaters, separated by moisture-resistant glass wool. They are covered with a thick heat-insulating layer of glass wool. The heating elements are made in the form of mesh strips 250 mm wide, placed at a distance of 100 mm from each other and connected in series by soldered copper plates.
The maximum temperature reached by the heaters is 180°, on the contact surface "blanket - concrete" up to 80°.
The blanket can be successfully used for many other construction needs: warming up the soil in winter, drying and heating floors, bases for a soft roof.
Hydraulic muscles. The wrench for tightening nuts is still a manual tool, and this operation is difficult to mechanize. True, pneumatic or electric wrenches have long been used on assembly lines. But this is, firstly, in the stationary conditions of the enterprise, and secondly, with limited rotational loads transferred to the hands of the worker. But what if the installation takes place in the field, say, on the laying of an oil or gas pipeline, and you have to tighten the nuts the size of a saucer?
To facilitate such a labor-intensive operation, a mechanized tool complex developed by NTTM participants, innovators of the Neftekhimmontazh trust of Glavneftemontazh of the USSR Minmontazhspetsstroy is called upon. It is a machine for tightening large diameter threaded connections on the flanges of pipelines and equipment operating under high pressure. It consists of a portable pumping station, a hydraulic jack with brackets and a set of special spanners.
The pumping station, which creates the necessary force on the tool through a high-pressure hose, is assembled from a single-plunger pump, an oil reservoir with a pressure gauge and a drilling machine that acts as an electric drive. The reciprocating motion of the pump plunger is given by an eccentric roller mounted on the machine spindle and pushing the plunger head during rotation.
1 - hydraulic tong bracket, 2 - hoses, 3 - hydraulic jack, 4 - handle, 5 - plunger tip, 6 - pin, 7 - comb, 8 - wrench, 9 - flange, 10 - pressure gauge, 11 - pump (НРД-400) , 12 - eccentric roller, 13 - electric drilling machine (IE-1023), 14 - oil reservoir.
A special wrench with a special comb on the lever is put on the screwed nut to engage with the tip of the hydraulic jack. The hydraulic jack itself on a bracket with a hole of a suitable diameter is installed on a nut adjacent to the screwed nut. In this case, the finger of the tip at the jack plunger enters the corresponding groove at the wrench comb. The pump is turned on, and under liquid pressure (200 kgf / cm 2), the plunger through the tip presses on the key lever, creating a force of over 5 thousand kgf. This makes it possible to effortlessly tighten nuts with a threaded hole diameter of up to 102 mm and wrench sizes up to 146 mm.
With the help of a complex tool, you can also unscrew threaded connections of large diameters, selecting in each case the appropriate wrench and bracket for the hydraulic jack.
Vibration tamer. Air plays such an unusual role in the pneumatic tool introduced by the NTTM participants at the Kolomna Diesel Locomotive Plant named after VV Kuibyshev. For processing hard-to-reach places in dies, molds and parts of complex configuration with grinding heads, a small-sized machine powered by a compressed air network is used here. The novelty compares favorably with the existing tool. One of the important advantages is that its handle is designed to dampen the vibration that occurs on it during operation.
How to unscrew the pin? Consider several ways, taking into account the condition of the stud and the available tool.
How to unscrew the stud by the threaded part
If the stud is long enough and the threaded part for 2 or more nuts is available, then we use one of the following methods:
- screw the nut, screw the second one all the way into the first one (it is advisable to use high nuts), after which unscrew the stud with a locksmith tool (wrench or other);
- use a special tool - a stud driver, for the size of the stud or universal.
How to unscrew the stud if only 1 nut thread is available? In this case, at least 4 methods are available:
- cut the nut on one side with a hacksaw (cutting direction is along the axis of the threaded part), screw it onto the stud, tighten it with a pipe wrench so that the threaded part, choosing the gap in the section, tightly grabs the stud, direct the force in the direction of unscrewing;
- screw the nut onto the thread, weld it to the stud (for example, with a semi-automatic welding machine) and unscrew it with a key (or a head with a knob);
- screw the nut onto the thread, drill a recess in the end of the stud (approximately half the diameter of the stud), drive a TORX nozzle (E-profile, or another similar one with longitudinal ribs) into this recess and unscrew the nozzle by the shank (you can help with the force of the second hand with an open-end or ring wrench that applies force to the nut in addition to the main force on the torx);
In the screwdriver method, the large version or the power version with a T-handle is better suited for this purpose.
How to unscrew the stud for a smooth cylindrical part
If only a smooth section of the stud is available (for example, the threaded part is broken off), then the following techniques are applicable;
- clamp the cylindrical part in a suitable tool (pliers, pipe wrench, small vice, clamp or other) and apply force in the direction of unscrewing;
- weld a metal bar to the broken end by welding as a T-handle;
- put on a nut of a slightly larger diameter, weld it to the stud in a circle and unscrew it with a wrench;
- use a square washer with a thickness of a nut or more, with an inner diameter of the same size as the diameter of the cylindrical part of the stud (ideally, if the washer sits on the cylindrical part of the stud with an interference fit), cut it on one side similarly to the nut in the previous subsection, put it on the stud, tighten pipe wrench and unscrew;
- use a die (the one used for threading), turning the end of the stud to the square of the desired size;
- use a hairpin;
- with a hacksaw for metal, make a cut at the end under a flat screwdriver, with which to remove the stud.
How to unscrew a broken hairpin
If the pin is broken and there is no part protruding above the surface, then you can unscrew it in the following ways:
- gradually and accurately “build up” a couple of centimeters with a semi-automatic welding machine (if the end of the stud is in the zone of reach of the welding wire) and for this “build-up” is turned out using a clamping tool;
- use a special tool - an extractor (it looks like a tap, the working part is conical, the direction of the thread is opposite to the thread of the stud): align the protruding end of the stud with a file (or even saw it off with a hacksaw), punch exactly in the center, drill a hole of the desired diameter along the axis of the stud and depth (approximately 2/3 of the length of the working part of the extractor), insert the extractor and rotate with force until the pin is unscrewed;
- preparation with drilling as in the previous method, only apply a tap on the left thread of the stud (if the stud is in the right direction) - when the tap, cutting the thread, rests on the bottom of the drilled recess in the body of the stud, the chip is often unscrewed;
- drill the center of the stud, choosing the diameter so as not to touch the threaded part of the socket, and then remove the remaining metal of the stud;
- drill out the broken part of the stud and the threaded socket on a drilling machine or with a hand drill with a larger diameter drill for the repair stud.
It can be difficult to align the end of the stud if the break occurs in depth. In this case, the end burr will be invaluable help.
Another variation for the drill method. You can use drills with a left-hand direction of rotation and an electric drill with a direction switch and speed control. When drilling at low speeds, the wedged thread loosens and due to the left rotation of the drill, the rest of the stud is easily pulled out of place and comes out of the threaded socket.
Drilling is often wiser to do in several passes, from a small drill to those that are larger, to the desired diameter.
How to unscrew a stuck hairpin
A soured hairpin must be unscrewed with additional tricks, both in terms of tools and in terms of methodology.
- apply several hammer blows to the end of the stud along its axis without damaging the edge of the thread;
- apply several light blows from different sides on the side surfaces of the stud (at the same time screw the nut onto the threaded part to prevent damage), while preventing bending;
- apply special penetrating compounds - WD-40, liquid key and their analogues, giving the necessary time in accordance with the instructions for these drugs from their manufacturer before trying to unscrew;
- use an extension to the hand tool to increase the applied force (a longer crank or by putting a pipe of a suitable diameter on the rotating end of the hand tool;
- when unscrewing the welded nut, use not an open-end wrench, but a Super Lock head, in which the force is applied not to the corners (edges), but to the planes;
- instead of applying physical force and a hand tool, use an impact wrench (if it is not in the home workshop, then you can contact the nearest tire service or car service, delivering the part with the stuck pin there);
- when screwing two nuts, screw the first one all the way with so much force that it cuts into the cylindrical part of the stud, and use the second nut not a standard one, but a self-locking one (this will allow you to use much more effort, reducing the risk of idle unscrewing of the nuts);
- heat several times and let cool, at the final stage heat and unscrew.
When unscrewing a stuck stud by a welded or screwed nut, it is better to use the tool that is structurally stronger and more tightly covers the perimeter of the working surfaces of the nut, excluding licking of the edges:
- 6-sided head instead of 12-sided;
- Super Lock head instead of the usual one;
- box wrench place open-end wrench;
- collar instead of a ratchet.
How to unscrew the stud from the exhaust manifold
If the steel stud is stuck in a steel or cast iron manifold, then you can heat it until the metal turns red using a carefully gas cutter, gas burner from a spray can, a blowtorch, or other suitable equipment.
How to unscrew the stud from the exhaust manifold to prevent cracks in the cast iron? First of all, it is impossible to artificially intensively cool the cast-iron part. At the same time, it is necessary to heat the collector itself, without touching the stud: the collector will warm up and expand a little in the area of the threaded hole with the soured stud, and the difference in heating of the parts will further weaken the sticking.
How to unscrew a stud from an aluminum part
Parts made of aluminum and its alloys cannot be intensively affected by a gas cutter and other powerful equipment due to the risk of parts melting or otherwise being damaged by high temperatures. In this case, you can:
- you can only heat the hairpin and then not to red;
- use a hot air gun (thermal gun) to heat an aluminum part or use a blowtorch to a limited extent in a more gentle temperature regime than a gas burner can provide.
How to unscrew the stud from the engine block
First of all, when choosing an approach, one must proceed from the material from which the engine block is made. In the case of a cast iron block, we use the approach of intense heating until reddening with a gas burner. If the block is aluminum, then in the area of the coked stud we warm it up gently with a hot air gun, preventing damage to the expensive part from high temperatures.
For example, it is often very difficult to unscrew the pin from the ZMZ 402 engine block. It is distinguished by systemic problems with unscrewing certain studs due to the material of the block and the characteristics of its heating during operation.
Several cycles of heating and gradual cooling will greatly facilitate the unscrewing of the stud from block 402. Recall that the unscrewing of the stud is carried out in a heated state. It will also be very useful to have a shock effect on the hairpin - along its axis or loosening with blows on the sides from different sides.
How to unscrew a broken stud from the block, we outlined above in a separate subsection, the techniques for this part are not original.
How to unscrew the stud from the cylinder head (cylinder head)
When deciding how to unscrew the stud from the cylinder head, one must also proceed from the material of the head. Cast iron heads are rare, mostly on older cars, and most often they are made of aluminum alloys.
On block heads, you often have to deal with stuck, soured studs.
To unscrew the stud from the cylinder head, you can use the most convenient and effective methods and techniques listed above. Often this is the two-nut method, the use of an extractor, or drilling. To enhance the impact, it is more expedient to apply a preliminary loosening tapping on the sides, the use of penetrating compounds, and rotations with two tools.
Conclusion
Faced with the question of how to unscrew the stud from the block, head, manifold, starter, wheel hub or other part, you can choose an effective solution to the problem from several methods and techniques, taking into account the available tools and tools. Locksmith tools available in almost any garage, as well as specialized ones, such as a stud gun, can be used.
Before unscrewing the stud, it is worth applying a shock effect to it. Also, if the threaded socket in the part is through, and the end of the stud sticks out, then the visible part of the thread should be cleaned of contaminants, which can create additional difficulty when unscrewing. The preliminary application of penetrating compounds also facilitates the extraction operation.