One of the most successful devices for body repair is a reverse hammer. The reverse hammer is successfully used during the repair of thresholds, arches, pillars, where there is no access from inside. The design of the reverse hammer is very simple; the base is a steel rod with a diameter of 20 mm. and 500 mm long, a weight (bushing) is put on it; on one side, the rod is made in the form of a hook, and on the other, a washer is welded so that the bushing does not fly out, and the impact force of the return hammer is transferred to the rod.
Principle of operation; Before starting work, you must familiarize yourself with the repair area of the car body; the areas to be pulled out should be cleaned down to metal and repair washers should be welded. Next, use the hook of a reverse hammer to cling to the washer and pull out the dent with light blows, repeat this operation until the dent is completely removed. To remove oblong dents and edges, a metal rod is welded through the holes by inserting several washers.
Important: Never use a back hammer for repairs. large areas body, these are the central parts of the roof, hood and trunk lid, since as a result of welding the washers, the metal can be greatly pulled out, the result will be a deplorable part in a landfill. There are also reverse hammers with two or three weights, which allows you to adjust the impact force.
DIY reverse hammer
To make a reverse hammer, you will need a steel or stainless steel rod with a diameter of 20 millimeters and a length of 500 millimeters, a steel weight (bushing), an ebonite handle and a hook. You can make your own hook from sheet metal 4 mm thick. It should be noted that to make a vacuum reverse hammer, instead of a hook you will have to use a plunger suction cup, no matter how funny it sounds.
Important: All parts of the reverse hammer must be filed and all burrs and serrations removed. Don't forget the reverse hammer hand tool, Make it so that it is pleasant to hold in your hands
Vacuum return hammer
For body repairs without painting, vacuum reverse hammers are used, since they do not disturb the external paint of the car body. In addition, they can be used when repairing large areas of the body.
A back hammer is a hand tool designed to create a retracting force. If a regular hammer is used to hammer or deform a surface away from itself, then a device with a reverse action pulls the metal towards itself. Such equipment is used in body repair, in particular when straightening, and it is also used when it is necessary to tighten the bearing when it is not possible to hit it with reverse side. Reverse hammers are rare because they are designed to perform highly specialized tasks that the average car enthusiast or mechanic does not need. The tool can be found in automobile service centers, as well as those drivers who have encountered self-straightening of the body.
How does a reverse hammer work?
The reverse action hammer is a metal pin about 50 cm long. Its diameter is 20 mm. There is a handle on the back of the tool. A freely movable weight is mounted directly on the pin itself, made in the form of a thick-walled tube, the length of which is adjusted to the size of the palm. The front end of the hammer is fixed different ways to the surface to be pulled. To work, you need to grab the weight with your right hand and the hammer handle with your left. To create a pulling force, you need to pull away with a sharp movement right hand with a weight in the handle. This creates a blow, from which the hammer pin moves in the opposite direction, dragging the deformed surface along with it. Thus, almost the same effect is created if it were possible to hit with a regular hammer on the back side of the dent.
The working end of the hammer is fixed to the deformed metal using a vacuum suction cup, glued or welded attachment. If you need to work with the edges of the car body, then hooks and clamps are used. Each type of fastening has its own advantages and disadvantages, and therefore can only be used in certain cases.
The classic device of a simple hammer with reverse action is described. There are more advanced models that are equipped with additional devices that make work easier. Most often, they have removable attachments for fixing to the surface being treated, as well as a set of weights different weights. Thanks to this, you can select components to ensure more efficient performance of the job. For example, if the installed weight is too heavy and the metal of the body is thin, then instead of a straightened dent you will get a hump that will have to be pressed back.
How to use a hammer
It is worth noting that a reverse hammer is a tool that needs to be handled very carefully. If you overdo it and apply too much force, other defects may form when aligning the dents. Auto body repair specialists do not recommend using a blowback hammer on very large dents that are present on the roof of a car or trunk. These parts are relatively easily accessible, so it is quite possible to remove interior lining and apply pressure from the reverse side to squeeze the metal into its original place. In the same case, if a dent has formed on the side of the car, and especially on the sills, then using a hammer will be more than justified.
To accurately straighten a dent, you need to secure the tool pin at its beginning. It is unacceptable to immediately fixate on the center of the defect, since when pulled back the metal will be crumpled and sharp corners will be obtained. Often, when using a hammer on dents without sharp kinks, you can level the surface so much that the previous defect will be completely invisible. There is no need for putty or paint.
On significant defects you need to work slowly and smoothly. First, the rim of the dent is pulled back, as a result of which its diameter and depth will gradually decrease. At the final stage, the central part is pulled back. If the tool is attached to the body by welding, after each pulling it is necessary to cut off the fixation and grind the seam. It is unacceptable for weld residues to remain on the metal, since it acts as an additional stiffening rib, which interferes with work at other fixation points. Using a reverse hammer is a lengthy process that cannot be rushed.
When using a reverse hammer with fixation by electric welding, after each welding you need to allow the metal to cool, since the hot area stretches much more easily and does not drag the cold part of the dent along with it. It is also worth considering that it is unacceptable to start work if there is dirt, chipped paint and other deposits on the surface being treated.
Types of hammers
Reverse hammers differ in the method of fixation to the surface being processed. According to this criterion they are divided into types:
- Vacuum.
- With glued suction cups.
- Welded.
- Mechanical.
Vacuum return hammer
The vacuum reverse hammer is the most expensive and yet very effective. The tip of this tool resembles a regular household plunger used to clear a clog. sewer pipes. At the end of the hammer there is a rubber plate that is applied to the dent. The tool is connected to a pump that pumps out air between the rubber plate and the car body. As a result, the suction cup is securely fixed to the metal. After this, the hand holding the weight is sharply pulled back and a reverse thrust, pulling out the dent.
Typically, a set of vacuum hammers comes with 3 rubber pads various diameters. The larger one is used for processing wide dents, and the smallest one for small defects. Such a hammer, when connected to a compressor, creates quite a lot of clamping power. The plate is applied not only to absolutely flat surfaces, but also to flat ones, which is especially important for cars with a streamlined body. The vacuum type tool is quite lightweight and often weighs no more than 1.5 kg. The only inconvenience is the hose from the compressor.
The main feature of a vacuum suction hammer is that it can pull out a dent without having to remove a layer of paint. If the car has received a minor defect, it can be corrected with minimal costs without the need for puttying and applying a varnish layer.
Reverse hammer with glued suction cup
There are also reverse hammers that come with rubber pads. Such suction cups are glued to the car body using glue. After hardening, a hammer pin is screwed into the thread on the plate. Next, the usual alignment is carried out by sharply moving the weight. After the area is straightened, the hammer pin is unscrewed, and the glued suction cup is heated. When heated, the glue becomes viscous and the pad can be easily removed. After this, the surface is treated with a special solvent to remove any remaining glue.
The disadvantage of this tool is that the glue does not set when low temperatures. In this regard, it will not be possible to carry out editing in winter without a warm box. This method allows you to level out dents even without removing paint. The suction cups are glued directly on top of the varnish layer without corroding or damaging it. The formula of the glue differs from the composition of the paints, so the solvent does not take them, which eliminates the risk of color blurring when cleaning the surface from residual adhesive.
Reverse hammer with welding fixation
The most common are hammers with fixation using a welding machine. A nut is welded onto the body, into which the tip of the hammer is screwed. After this, the dent is pulled out. This tool has a number of disadvantages. First of all, this is due to the fact that its use requires availability. When working, you must first clean the surface to be straightened. The paint layer is removed to bare shiny metal. After this, the nut is spot welded and pulled out. Next, the nut is cut off and the surface to be straightened is sanded. At the end, the fixing element is digested to another point, and the action is repeated.
In fact, after the flaw has been corrected, it is necessary to putty, primer, paint and varnish so that the corrected part becomes uniform with the rest of the body surface. A similar tool is used in cases where there is a significant defect. Since the fixation is carried out using a weld, such a reverse hammer can be used even in the cold, unlike glued suction cups.
Mechanical hammer
The mechanical return hammer is an almost similar design with welded tools. The only difference is that its attachments are hooks and clips. With such a tool it will not be possible to straighten the central part of the dent, since the hook can only be fixed to the edges of the body. Craftsmen who only have a mechanical tool with hooks at their disposal can cut a hole in the body and hook onto them. After correcting the defect, the resulting slots are welded and ground. Since the hooks can be twisted, it is quite possible to pick up a regular nut and weld it to the dent. Thus, a mechanical hammer can be used as a welded one.
The main function of mechanical hammers is to remove bearings. They are usually used to repair the chassis of a car when there is no access to the back part of the bearing to make a blow. Often the kit comes with special clamps that allow you to grip the joint cage at 2-3 points. Thanks to this, dismantling can be carried out without destroying the old bearing.
Any type of body work is expensive and requires special skills and tools. However, you can save on buying some by building them yourself. For example, you can make a reverse hammer with your own hands in an hour. This will allow you to independently carry out and control the process of leveling dents on the body in hard to reach places.
There are several options for the reverse hammer structure:
- vacuum;
- with pneumatic pulling mechanism;
- devices with multiple weights;
- models with an adhesive base or replaceable nozzles.
The first of the presented types has a unique advantage over similar devices. The vacuum suction cup allows you to produce renovation work no damage paint coating. Depending on the power of the vacuum reverse hammer, it is possible to pull out small and medium-sized damage onto various parts body However, when working, it is necessary to follow a special technology: pulling should be done from the edge of the damage to its center. Otherwise, a dangerous stress for the metal arises, which can lead to fracture or unpredictable deformation.
Pneumatic reverse hammers are convenient because they require reduced effort when performing work. Another area where this tool is indispensable is work under the hood, including removing stuck parts.
A homemade reverse hammer can be built from the simplest components:
- a metal rod of suitable thickness and about half a meter long;
- steel washers of the appropriate diameter for installing stops;
- weights to increase impact force;
- rubber handle (can be replaced with any other convenient material);
- hook or metal plate with a holder - depending on the design of the intended hammer.
The condition of all components determines whether grinding and cleaning will be necessary. metal parts. For this you can use sandpaper or a disc for grinding metal, and may also come in handy special compounds. The design features will determine whether a welding machine is needed or only a thread cutting device is required. However, most often it is impossible to do without welding, since it is better to secure the lock washers to the rod of the reverse hammer using a reliable seam.
You need to select an iron rod that will be 3-4 cm thicker than the base of the reverse hammer and saw off a part 5-7 cm long. A hole is drilled inside to suit the thickness of the rod. The thread is cut inside at a right angle so that the plate welded further is strictly perpendicular to the working handle. This area should be well sanded and cleaned, and outside a ribbed texture is artificially created so that the sticky base interacts better with it.
Homemade Velcro sealant for a reverse hammer can be made from various materials. The adhesive composition must meet several characteristics:
- it should not leave marks on the car’s paintwork;
- its degree of interaction with the surface must ensure reliable adhesion;
- the composition must be sufficiently elastic.
For this purpose, you can choose any household composition. For example, scraping it off the parts from which they are made plastic windows or use resin, which can be purchased at a hardware store.
Sliding hammer with additional attachments It’s also easy to do it yourself. To make it you just need to apply a thread to the base. At the same time, future nozzles of the reverse hammer will need to be made with a diameter larger than the rod, several centimeters - this will ensure reliability during operation. If you already have attachments and they are all designed for different rods, you can make an adapter for the reverse hammer with your own hands or purchase a ready-made one at any automotive store.
The use of a reverse hammer in dent pulling work has proven effective when working on arches and sills where available inner space not much. It can also be used for minor damage to the doors and body if the stiffener is not affected. Self-production using a reverse hammer will save you a significant amount.
Body repair is a complex operation that requires certain knowledge, special tools and equipment. One such device is a reverse hammer. This is a simple tool that is easy to make with your own hands. There are many photos and videos for this on the Internet. You can also download a drawing of the simplest version of the device.
What is a reverse hammer and what is it used for?
This tool is a device that allows you to apply a certain force to an area of metal with limited access. A device is used to level small areas of a deformed car that have suffered from minor accidents.
Some areas of the car body can be leveled with a regular rubber hammer, using blows from the reverse side. However, most surfaces do not have such access. In such cases, a reverse hammer is necessary. Its tip is fixed at the point of deformation, and with the help of a load located at the other end of the device, a pulling jerk force is transmitted to the surface.
Before making a reverse hammer, it is necessary to describe the types of this tool. This will be needed to make a drawing of the device you need, and then make it.
Types of reverse hammer
Despite its simplicity, this device has acquired several versions over time. Each option is used in individual cases, which depend on the type of damage and the skill of the specialist. In general terms, the design of this device is the same, as is its principle of operation. The only differences are in the method of attaching the tool to the body.
The most common reverse hammer is a metal rod with a hook at one end and a weight with a stop at the other. The hook hooks onto a washer welded to the deformation site. By applying impact forces to the load, the deformation is stretched to the desired point.
The second, equally simple version of the reverse hammer differs from the previous one in that there is a regular thread at the end instead of a hook. To level the surface with such a device, you need to make a hole in the center of the deformation, insert the threaded end there, and fasten a washer and nut to it on the back side.
The most complex type of this device has a vacuum device at the end, which is fixed to the surface of the deformed part using rarefied air. The suction cup can be driven either by a compressor or by the usual method. This type of device allows the straightener to correct simple damage to the body, and at the same time preserve the paintwork of the area, if it is not damaged.
Self-production
Making a reverse hammer at home with your own hands is quite simple. It does not take much time and does not require special materials and tools. For a clearer understanding, you can watch a video on the Internet. A primitive drawing will also not be superfluous.
To make this tool with your own hands you will need the following:
- metal pin about 50 cm and 20 mm in diameter;
- a load that has an internal opening;
- thread cutting tool (optional);
- welding machine;
- Bulgarian.
If you decide to make a reverse hammer with a hook type of fastening, then a hook is made at the end of the pin. This can be done using a vice or pliers. Or weld welding machine already ready hook from another device.
If the tool is made with a threaded grip, then the end of the pin is threaded with the appropriate tool. You should not cut a lot of threads, since the metal of the body is quite thin.
After making the tip, a weight is put on the pin, which is limited on the back side of the tool. This can be done by welding, or using a threaded stop. The second method is more advantageous, since it will allow you to use weights of different weights depending on the required force at the end of the reverse hammer.
Again, to clearly understand how this happens, the easiest way is to watch the video. If this is not possible, then the procedure for working with this device is approximately as follows:
- the tip is fixed on a deformed area of the body;
- by hitting the load on itself, the part is leveled to the desired position;
- if the effort is not enough, then the load is changed to a heavier one.
When pulled relatively large plot metal, you can weld several washers on one line and thread a pin through them. To do this correctly, it is advisable to watch a video on this topic. This pin is then engaged by a hook, which is welded to the fixture and pulled back along with the metal, aligning it to the desired condition. Be careful when using this method, as welding large number washers can excessively pull the metal and damage the body part.
This type of automobile repair, such as body repair, is a rather complex operation. You will need a number of special knowledge, as well as equipment and tools. The reverse hammer plays an important role in body repair. This tool is quite simple and can be made independently without any problems. Moreover, there are many recommendations and videos on this topic, as well as drawings.
Today you will learn how to make a reverse hammer with your own hands and how to properly use it for its intended purpose.
Action
This device is used to level minor areas on deformed cars after minor accidents.
There are areas of the body that can be leveled using a simple rubber hammer, performing reverse blows. However, such access to most surfaces does not exist. This is why you need a reverse hammer. The tip of the hammer is attached to the deformation site. Using a weight at the opposite end, a jerky pulling force is applied to the surface.
Before you start making a reverse hammer for body repair with your own hands, you will need to understand how this tool works and what types of it exist. It is also recommended to make a drawing. And only after that you need to start working.
Varieties
Despite the fact that the design of the reverse hammer is quite simple, over time even it has had several modifications. This or that option is used in different cases - it all depends on skill, as well as the type of deformation. But in general, the design is always the same, the operating principle is the same. The differences lie only in the method of attaching such a tool to the body.
The simplest version of the hammer:
- This is a metal rod, at one end of which there is a hook, and at the other - a load and a stop;
- A hook is attached to the washer, and the washer is welded to the place of deformation by welding;
- Provided impact forces are applied to the load, the deformation is extended to the desired moment.
But the second option (also quite simple) will differ somewhat from the first. At the end, instead of a hook, there is a simple thread. In order to level the surface using such a device, a hole is made in the center of the deformation, into which the threaded end is inserted, and a nut and washer are attached to it on the reverse side.
Vacuum hammer is the most difficult option its execution. He attached to the surface of the deformed area through rarefied air. The suction cup begins to work both in the usual way and with the help of a compressor.
Thanks to the vacuum device, minor body damage can be repaired and the paintwork can be preserved intact.
Manufacturing
Making such a device yourself is not that difficult. No special tools or materials are required. And it won’t take much time for this. To have a clear idea of the work, you can watch a training video and also make a rough drawing.
If we talk about tools, then for work you will need the following:
- Metal pin 50 cm long and 20 mm in diameter;
- Weight with internal hole;
- It is advisable to have a thread cutting tool;
- Welding apparatus;
- Bulgarian.
If you want to make a hammer with a hook type of fastening, then make a hook at the end of the pin. It can be made from pliers or a vice. Another option is to weld a ready-made hook from another tool.
If the tool grip is threaded, then cut the thread on the end of the pin with a special tool. There is no need to cut it much, since the metal of the body is quite thin.
When the tip is ready, a weight is placed on the pin, limited on the back side of the tool. This can be done using a threaded stop or by welding. A threaded stop is a more acceptable option, since you can use weights of different weights depending on how much force is needed at the end of the tool.
Application
Such a tool has next principle works:
However, along with the advantages, such a hammer also has a number of disadvantages. Because of them, it is possible, together with the existing dent on the body remove the previously intact layer of paint. In addition, this tool is not suitable for repairing large dents on the hood, roof or trunk surface of a car. And welding staples can damage the metal, which means the part will need to be completely replaced.
Vacuum return hammer
There is a separate type of device - a vacuum hammer. Vacuum straightening of a car body has its own peculiarity, thanks to which it is possible to put in order a fairly large damaged surface of the car.
Its advantage is that it has a vacuum suction cup, thanks to which there is no need to remove a thick layer of paintwork before starting body repairs. More compared to a conventional tool no need to drill or weld staples in the area subject to repair. In this case, caps of different configurations and shapes are used. Using a vacuum suction cup, the material is well held when leveling the dent. Working with a vacuum tool will reduce work time and labor costs.
Vacuum straightening of the body is carried out as follows:
- First, the area to be leveled is cleared of fat and warmed up;
- The dent in the center and edges is glued with glue pens the right size. The pistons are engaged with a vacuum hammer, and the impact on the surface is quite accurate;
- Repeat the previous two steps in turn until the surface of the body takes on its normal shape;
- At the end, after leveling, it is well worked out using a mini-lifter, which comes complete with pistons.
Despite the obvious advantages of vacuum extraction over conventional leveling, this method of body straightening also has its disadvantages. It is not possible to completely remove the defect. Moreover, if there were cracks in the damaged area, then you risk damaging it even more. Accordingly, you need to be careful when choosing a straightening method, as well as choose the right tools for the job.
As you can see, a reverse hammer is indispensable tool for carrying out body straightening work. It has many disadvantages, which we discussed above. But despite this, only with its help can you get rid of dents in hard-to-reach places. Therefore, it must be present in the arsenal of tools of every automobile mechanic.
