Reverse hammer: types, principle of operation, purpose

Design and use of a reverse hammer, making a tool with your own hands
What is a reverse hammer for body repair?
Purpose and types of reverse hammers
How to use a reverse hammer
We manufacture our own reverse hammer

Many drivers, when faced with the concept of “reverse hammer,” do not understand what it is. Although, if you have never had to do body repair yourself, there is a high probability that you have never seen such a tool. But if you still have to repair the body, you cannot do without a reverse hammer. In this regard, the purpose of the article below is to tell not only what a reverse hammer is, but also how to make a reverse hammer for body repair with your own hands.

What is a reverse hammer for body repair?

In the process of working with a car body, the hardest and most important part is straightening, that is, leveling the surface of the body. To perform this task, even specialists need to have professional equipment on hand, which includes a reverse hammer.

In addition to this, many reverse hammers also have hooks, with which the device can grab staples welded to the body, and thereby be securely held on it during straightening.

Purpose and types of reverse hammers

Often, a back hammer is used to remove small dents on metal parts of a car body that either cannot be accessed directly or need to be leveled from the reverse side. Using a reverse hammer is very convenient for working with car sills, wheel arches and pillars.

There is a classification of reverse hammers for body repair, which includes:

• With weights (two and three are used).

• Reverse hammers operating thanks to a pneumatic mechanism.

The specificity of straightening work depends on the type of reverse hammer. To level the surface of the body of a new car, it is better to use a vacuum return hammer, since only it allows you to perform such complex work without first removing the paintwork. In the same case, if you are going to use one of the remaining types of hammers, the part of the body where the dent is located will first need to be thoroughly cleaned with sandpaper. Otherwise, the paintwork will still be damaged by the reverse hammer.

How to use a reverse hammer

The entire process of straightening dents on a car body using a reverse hammer should be performed in the following order:

1. Rinse the entire work surface with water to remove all contaminants, and be sure to treat the entire surface with a degreaser.

2. If necessary, remove the paint coating from the work surface. To do this, it is more practical to use a grinding machine.

3. Weld round repair washers to the area with the dent.

4. Attach a special hook to the reverse end of the hammer, which should come with the tool.

5. Hook the hook onto the washer.

6. While holding the tool by the handle with one hand, grab the weight with the other hand and point it towards the handle. In this case, your movement should be as sharp as possible.

Due to the fact that the reverse hammer is tightly coupled to the body surface, with each of your movements with the weight, the reverse dent is leveled. At the same time, the harder you hit the weights, the faster the process of straightening the car body will go.

You must be extremely careful when working with a reverse hammer. Do not rush under any circumstances and after each impact evaluate how the dent has changed. This will help you avoid creating new dents at the edge of an existing defect. But if you work slowly and follow all the instructions correctly, you can remove a small dent in just a few minutes.

CV joint puller: types and principle of operation

The general technique for removing a grenade from an axle shaft is quite simple - you need to pull the nodes in opposite directions with great force. This cannot be done by hand; you need a mechanical puller for the CV joint.

The inertial tool works according to the familiar principle of a reverse hammer. With its help, you can remove the CV joint without removing the entire suspension assembly of the car. One part of the hinge is fixed to the axle shaft, and the dismantled middle is removed for maintenance. Using a special eye, the hammer guide is attached to the axle shaft with a hub nut. A few sharp blows are enough, and the spline joint, compressing the locking spring, comes out of the holder without damage.
CV joint boot puller, working on the wedge principle. To create the spreading force, two support platforms are required. We create one of them using clamps placed on the removable CV joint axle shaft. The second is made in the form of a split ring. It rests against the clip, like on silent block removers. Wedges are inserted between them (on both sides to ensure uniform force). How to apply the effort is not important. Typically, wedges are driven in using two hammers of equal weight. It is enough to move the axle shaft by 3-5 mm, and the retaining ring is compressed, freeing the movement of the part. There are also pneumatic boot removers.
It is convenient to use a screw puller when the entire CV joint is removed from the car. This bulky design allows you to work with units of any size, since the length can be adjusted. A homemade CV joint puller is made for a specific car, while a factory tool is more universal. It consists of two thrust (more precisely, tensile) platforms connected by longitudinal rods (rows of holes are located on the rods to adjust the distance between the supports). One platform is fastened with a clamp, the second with its eye is put on the threaded connection of the axle shaft. By rotating the hub nut, you create enough force to compress the retaining ring.

Such devices make it possible to save on visiting a car repair shop. You can purchase the tool at any auto store: both universal and for specific CV joint models.

Brands of PDR tools

Now there are many different companies producing PDR tools and accessories. It is better not to buy cheap analogues from unknown companies or even kits without a name. Tools from well-known, proven brands are thoroughly tested and tested by experienced paintless repair specialists. Specialists from PDR tool manufacturing companies maintain feedback with craftsmen and also take into account requests for the necessary modification of some tools.

The highest quality and most proven instruments are from American companies, such as Dentcraft Tools, A‑1 Tools , PDR Finesse Tools, Ultra Dent Tools and others. Also worth mentioning are KECO and Blackplague PDR, which sell innovative tools and adhesive system materials for pulling out complex deformations.

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 at 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

This tool has the following operating principle:

To begin, carefully examine the deformed area on the machine and select a suitable hook depending on its location, as well as the size of the dent - this will allow you to correctly calculate the accuracy of the applied force in the future;
Then thoroughly clean the damaged area on the body from the excess layer of paint, as well as primer down to the metal;
Next, weld special brackets (repair washers) onto the metal surface of the dent on the car using a welding machine. If an electric spotter is included with the hammer, then when leveling you only need to change the nozzle;
We hook the hook of the tool into the staples, then carefully and easily pull out the dent. It is recommended to do this until the damaged area of the body completely disappears;
To completely remove dents, first weld several staples, and then pull a tool rod through their holes so that the damage disappears;
We treat the corrected area with a primer and cover it with paint depending on the tone of the body.

However, along with the advantages, such a hammer also has a number of disadvantages. Because of them, it is possible to remove, along with the existing dent on the body, a previously undamaged 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.

Auxiliary accessories

Accessories for working with doors through a window opening (window protector PDR and wedge)

To repair door dents, PDR tools are typically positioned between the door panel and the door glass. To prevent damage to the glass, a window protector with a special wedge is used. All you need to do is lower the glass down, insert the wedge and protective protector, creating space for the tool to work. Also, instead of a wedge, an air cushion is used, which easily increases the gap between the glass and the panel, providing better access for the tool.

There are different types of protectors on the market, but the most common is a plastic or metal sheet with a right angle at the edge.

Before you start working with doors, you need to consider the type of glass installed in them. Typically, side windows are made of stalinite (tempered glass), but some modern cars may now have laminated side windows. For this type of glass, the pressure that can be applied to them during repairs (even through a plastic protector) is critical.

Before repairing, it is better to always check the glass of the door on which the dent will be repaired. Laminated glass can be recognized by its 2-layer structure, which can be seen at the top of the glass. If the glass looks like 2 layers glued together, this is a sign of laminated glass. In contrast, the layering will not be visible along the edge of a piece of tempered glass. It will look like a completely smooth, solid piece. Also in the corner of the glass there may be the designation “laminated” or “tempered”.

If the glass is laminated, it is better to follow the following recommendations to minimize the likelihood of damage to the glass.

Remove the molding at the top edge of the doorway.
Lower the glass so that it protrudes about 7–8 cm from the opening.
Use an air cushion to create space between the glass and the panel. Do not use a wedge for this as the pressure on laminated glass is dangerous.
Always use a metal glass protector for laminated glass.

Removing the molding from the top of the door allows more clearance to insert the tool between the glass and the door panel. This will provide enough space for the tool. By leaving 7-8 cm of glass raised, you can apply more even pressure to the center of the glass with the air cushion, rather than concentrating all the pressure on the top edge. The metal protector also helps dissipate the pressure you will apply to the glass with the tool.

Since laminated glass is easier to damage than tempered glass during PDR door dent repair, sometimes if the car is expensive, the safest way is to remove the door inner trim and glass.

Hood stand _ _

The bench is typically used to repair dents on the hood when they cannot be repaired on the car. The stand simplifies the work. The panel is firmly fixed on the stand and the master can easily access the back side at any point.

Modern stands have adjustments, which allows them to be used for hoods of different sizes, as well as for trunk lids. The stand folds easily for compact storage.

Stops, clamps, hangers

To repair dents on a car body, in addition to special tools, stops and clamps are required. It is important to fix the movable panel being repaired (hood, trunk lid or door) in a convenient position. For this purpose, special stops and clamps are used.

The hangers are designed to provide support and proper leverage for the hooks when repairing dents. Usually attached to the technological holes of the body. They come in different shapes and sizes. Carbines are also used for these purposes. They hold larger instruments while removing extensive damage.

Knives for cutting sealant

Knives for cutting sealant are necessary when repairing dents under reinforcements. The knife allows you to carefully cut off the sealant without scratching the paintwork. These knives are sharp and flexible. They can have different lengths and different handles.

How to make your own reverse hammer from an old shock absorber

VAZ shock absorber struts are best suited. After dismantling an old car, do not rush to scrap the old parts. With some effort and ingenuity, it is not difficult to make a reverse hammer from a shock absorber.

Device design

First you need to understand the design. In the classic version, a mechanical return hammer is a pin 50 cm long and 15-20 mm in diameter. On one side there is a handle, on the other there is a fixing device (hook, vacuum suction cups, threaded bolt). A steel sleeve—a weight—slides freely between them.

Device design

During the design phase, decide what other elements will be needed to make a reverse hammer out of the shock absorber. Draw up a drawing of the product and apply the required dimensions. Ready-made diagrams can be found on the Internet.

Required materials and tools

After properly disassembling the strut, you will have the necessary material to build a reverse hammer with your own hands from a shock absorber.

List of tools for work:

Bulgarian;
electric welding;
bench vice;
standard set of keys;
gas-burner.

Prepare a container for lubricant that flows out of the pipe cavity during cutting.

Disassembling the shock absorber strut

To create a useful puller, you need the top of an old part and a rod.

Disassembling the shock absorber strut

Clamp the part in a vice, place the dishes under the place where you will make the cut. Saw off the pipe to the plate with the spring. Work carefully, do not catch the rod.

Remove fasteners and other parts from the rack. You are left with the stem and top cap. Remove the oil seal and bushing from the latter.

Making a reverse hammer

The freed rod will serve as the basis from which a functional reverse hammer from the shock absorber will be obtained. It remains to equip the pin with three parts: a handle, a weight-weight and an attachment.

Further instructions:

At one end of the rod - where the thread is - attach a handle. Secure it by welding nuts on both sides. Treat the welding areas according to the rules: remove beads and irregularities with a grinder, sand them.
Make a movable weight from a piece of a shock absorber strut and a tube of the required diameter matched to it. Mount the element onto the main pin.
Attach attachments to the end of the rod opposite the handle.

Making a reverse hammer

The latter can be changed as needed: perhaps these will be hooks for leveling out dents on the car body, or you want to knock out soured grenades, hubs, or injectors. You can use vacuum suction cups and hooks at the end of the device.

How to make a handle

For convenient use of the device, find and attach rubberized side handles from power tools to one end of the main working rod. If there are no suitable parts, fit any clamp that fits comfortably in your hand.

Alternatively, use a piece of fuel hose. Secure it on both sides with nuts.

How to make a moving weight

The remainder of the pipe from the shock absorber strut will be used for this important part. The reverse hammer from the shock absorber rod is useless without a weight: its weight must be at least 1 kg.

The procedure for making a weight:

Select a pipe with a smaller cross-section than the piece from the rack, but larger than the diameter of the rod (the weight should slide freely along the rod).
Insert one tube into the other so that they do not touch the walls.
Center the parts, weld one end, leave the other open.
Melt lead and pour it into the gap between the pipes. After the metal has hardened, the weight is ready for use.

Reverse hammer from shock absorber rod

Lead can be “mined” from an old battery and melted into the housing of an unnecessary oil filter. Or, placing pieces of lead between the walls of the weight, direct the flame of a gas burner to the part.

Give the cooled weight an aesthetic appearance (cut off welding marks, sand it with sandpaper), put a beautiful heavy element on the rod. A do-it-yourself reverse hammer made from a shock absorber is ready.

Let's sum it up

Now you know how to make a reverse hammer with a suction cup with your own hands from scrap materials. I also recommend watching the video in this article, where you can familiarize yourself with thematic details. Any questions you may have can be asked in the comments.

A reverse hammer is a necessary tool that can be used to repair dents in hard-to-reach areas of the car body. These are parts of the car where it is impossible to squeeze out a dent from the back side.

These mainly include the arches, sills and pillars of the car. Such equipment is used for minor damage to a specific area, which does not require replacement of the entire fragment.

This tool is not complex equipment and is not large in size. It is the reverse hammer that will be discussed in this article.

Principle of operation

A body repair hammer serves as a useful tool for removing rough spots in difficult areas of the car. These include: thresholds, arches, pillars. The equipment is used only for small, insignificant dents, but with a powerful violation of the geometry of the body, a hammer alone cannot be used.

reverse hammer for body repair

In such cases, slipways are used. Repair using a reverse hammer is carried out as follows:

The area to be leveled must be cleaned and degreased.
Then use a sanding machine to remove the paintwork.
Weld repair round washers into the cleaned area. A welding machine is used for these purposes. If a reverse hammer is included with the spotter, then the process is simplified only by changing the nozzle.
You need to screw a metal hook onto the end of the hammer, which is always supplied with the tool.
Having hooked the hook onto the washer, you need to firmly grasp the metal weight with one hand and the handle with the other. Direct the weight towards the handle with sharp movements, thereby leveling the surface of the car. The stronger the blows, the faster the defect will be eliminated.

Car body straightening

A reverse straightening hammer restores deformed surfaces to their original appearance. If there are strong body errors, internal stress arises, which subsequently forms compression and tension. The nature of the dent plays an important role. For example, if irregularities form in the center of the body, new defects will begin to form during stretching.

If straightening is carried out correctly, stress due to deformation will be eliminated, and the body shape will return to its original even appearance. After leveling the surface, you need to carry out the direct forging procedure.

This means that those dents that the hammer did not level due to their small size must also be smoothed out. To do this you will need a counter support and an aluminum hammer.

Do it yourself

In order to make your own tool, you will need drawings of a reverse hammer.

reverse hammer without attachments included

They indicate the optimal parameters of the device, details of connecting parts and their quantity. How to make a reverse hammer with your own hands using available materials? For this process you will need the following items:

steel rod 2 cm thick (thinner is possible, but its service life will be shorter), 50 cm long;
handle made of rubber or ebonite (an ordinary nozzle will do);
stainless steel hook 4-5 mm thick;\
welding machine;
2 steel washers with a diameter of 2.5-3 cm;
weight approximately 16-17 cm long, 6 cm thick.

Tool making time is 30-40 minutes. The process is simple, so there should be no questions about how to make a reverse hammer yourself. With these items on hand, you need to do the following:

Clean and degrease the steel rod and, if necessary, sand the surface to a perfectly smooth surface.
You need to attach a hook to one end. It is best to do this using a welding machine so as not to waste time creating threads for twisting individual nozzles. After this, you need to thread one small (2.5-3 cm) washer and weld it near the base of the hook. This is necessary so that the weight does not fly to the surface being treated during operation.
It is necessary to make a hole in the weight with a diameter of 2.1 cm so that the part can move freely along the rod during operation. The shape of the weight should not have corners or protrusions, otherwise it will be inconvenient for the master to move it during repairs. It is advisable to weld round steel sheets to both ends so that the palm does not slip off the weight.
You need to insert a weight from the free end of the pin. If the movement is tight, increase the diameter by another 0.5 cm.
Before putting on the ebonite handle, you need to fix another washer, which will also prevent the weight from moving close to the handle. After this, you can attach the hammer handle itself.

PDR hooks (PDR rods)

PDR hooks are the staple tools that fill a craftsman's toolbox. Various in shape and size, they are used on every panel of the car. Most craftsmen use a rigid hook (or rod) 120 cm long for all open, fairly accessible places, such as roofs, hoods, trunk lids, fenders. Shorter versions of the same hooks are used for doors. Hooks can provide consistent and very controlled pressure to lift metal.

Hooks differ in length (from 40 cm to 2 m), bends, diameter and tip shape. It is better to have a set of different hooks, from which over time you can choose the ones that are most preferable for the job.

Some PDR tool companies create ratchet handle pdr tools. This is a great addition because the technician can use one tool for different positions and apply different amounts of force on the lever. Hooks are available with interchangeable tips, making one tool more versatile and saving space in your toolbox or bag.

Door hooks PDR (PDR door hooks)

Door hooks are used to work with door damage through the gap between the door glass and the panel, allowing you to straighten dents without having to remove the trim. Door hooks have different bending angles (from 90 to 180 degrees) and different lengths, with a narrow tip for better maneuverability. For ease of operation and increased functionality, door hooks can have a rotary handle.

These hooks are mainly used on the top of doors.

Brace tool (eng. brace - bracket, spacer)

Tools for use under panel reinforcements. There are versions for left and right hands. Designed to maximize reach and minimize ridges from tool use. This tool is often used to repair hail dents.

Dent Reaper

This type of hook is quite new. Dent Reapers provide strong pressure, do not bend, and have sharp tips for finishing.

Sickle/scythe hooks work well in doors and can also be used on other panels. They are “powerful” and precise in application. Increases work efficiency. Excellent for working with aluminum panels.

Knife-shaped/knife “shaved” hooks ( SHAVED TOOLS )

Knife/knife-shaped or “shaved” (from English shaved) hooks are designed to work in areas of difficult access, in narrow cavities, under amplifiers.

This tool is a hook with the barrel cut at an angle from the base to the working part. Shaved hooks come in different sizes. What they all have in common is slim design and flexibility. In terms of capabilities, these hooks are close to the “whale tail” tool, but they have a different principle of influencing the dent. Used to repair hail dents, especially under hood, roof and trunk reinforcements. Well suited for work in the rear fenders, where two metals are pressed closely together. Also good as an auxiliary tool, helping with finishing work in the final stages.

Due to the thin barrel, “shaved” hooks are not used on hard places, curves, or dense metal.

Whale tail

Whale tail instruments are named after the shape of their tip. They provide leverage at the edges of the tip. Whale tails come in different lengths from 10 cm to 150 cm with tips of different widths (from 1 cm to 10 cm - ultra-thin, thin, standard, wide and extra wide). The tips are completely rounded at the top.

They are used to work under panel reinforcements. Whale tail tools are not the easiest to learn. They work by twisting rather than pushing/pressing like regular hooks.

Jackhammer: characteristics of choice

Impact energy;
Number of beats per unit of time;
Power;
Weight;
Power source type.

Extra options:

Vibration and dust protection;
Shank type (hexagon, SDS-max, SDS-plus,);
Switch fixation;
Fixing the chisel in different positions;
Cable break warning system;
Electronic speed control.

The key characteristics in choosing a tool are the number of blows per minute and the value of the maximum impact energy. But in principle, you can also operate with the weight of the instrument, because it is directly related to its purpose.

We invite you to rent a power tool or specifically a jackhammer for any period at the most affordable prices to our company.

via the site form

PDR Tool Kits

Tools for paintless dent repair can be purchased individually or in kits. Kit sizes range from simple starter kits to complex professional kits. Before purchasing, it is better to study different tools so that you have an idea of what is offered to you.

It is better to buy tools not in sets, but separately. The kit may not include hooks, but may not include the tools you need. In any case, you need to study the assortment before purchasing.

Reverse Hammers

A back hammer is one of the most important tools for restoring a car body. It is used when there is no direct access from the inside to level out small dents. The design of such a device is extremely simple, and performing body repairs with it does not require special skills.

The main disadvantages of this tool:

before work, careful, lengthy stripping of the damaged area to metal is required;

it cannot be used for relatively large areas of the car body (the central part of the roof, trunk lid and hood), since welding washers can greatly pull out the metal, and the end result will be very disastrous.

restoration of thresholds, pillars and other body elements.

https://youtube.com/watch?v=Y1ffHedLhZs

Adhesive system

The PDR adhesive system is designed for pulling out dents from the face of a panel and includes a glue gun with special glue sticks, special pull-out clips, pull-out devices and a tool for removing glue from panels and clips.

Glue guns come in electric (corded or battery-powered) or gas. Glue sticks, as a rule, differ from the usual ones sold in hardware stores, have better adhesion, and are more durable. The rods come in different colors, which marks their characteristics. They mainly differ in the temperature at which the repair will be carried out, as well as the strength of the bond.
PDR Pull Clips come in different sizes, shapes, designs and colors. They can also vary in strength. As a rule, the shape of the clip is selected to match the structure of the damage. Now there are special reinforced long strips that replace several clips and make it easier to pull out complex dents.
Pulling devices. Once you have the clip glued to the dent, you will need a puller to pull one or more of the clips. For pulling, a sliding hammer, a mini-lift, a large lifting device, or a lever-type device is used. Different devices must be selected depending on the damage. Don't expect a blowback hammer or mini lift to pull out a dent in a panel and return the metal to factory condition with minimal effort. It is more correct to perceive these devices as one of many tools that you may need to achieve results. You may need to do several repeated stretches. You may also need to tap the high spots around the dent with a special punch and use PDR hand tools to finish the bumps.
Glue remover. Sometimes the adhesive is not easy to remove from the panel or clip, in which case you will need a tool to make the adhesive easier to remove. There are special formulations, and you can also use alcohol.

For professional use, harder types of clips are most often used, while softer clips provide less precise control over tension.

“Glue Pull Repair” (GPR), used without or in combination with PDR tools, has become a very powerful system thanks to its wide range of different types of glue, clips (or pull bars) and many pull devices. A modern adhesive system with all accessories and additional tools allows you to replace the use of a spotter and many other straightening tools.

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.

Tools with replaceable tips

Interchangeable tips allow you to use one tool in different situations, replacing several tools, which increases its flexibility of use and saves space in the master's bag or drawer.

Replacement attachments are designed for use with hooks, punches and hammers that are threaded for them. Nozzles or tips come in different shapes and sizes, and are also made of different materials, which gives them differences in properties (in particular, different hardness). The most common ones include coated, plastic, uncoated steel, pointed, rounded, and mushroom-shaped tips. Each tip plays a different role. Generally, the larger the dent, the larger the tip of the tool. However, you need to consider each dent, take into account its structure and choose the most suitable tips and methods of exposure. Typically, straightening starts with large tips to reduce the overall size of the dent, and then gradually reduces the tip size as the dents become smaller.

Let's look at the types of replacement tips installed on hooks and when they are used.

Tips are made of different materials (steel, plastic, rubber and others). Some have a coating (PVC or rubber) that acts as a damper to soften pressure on the panel. When using uncoated metal tips, you need to be careful and know what you are doing, as bare metal can damage the paintwork if pressed hard. Coated or plastic tips are safer in this regard.
Large mushroom tip with PVC coating. This tip is great for removing large, “soft” dents. It is suitable for quickly lifting large areas of metal. The mushroom shape is useful in cases where a lot of pressure is required on the dent. This tip provides very strong leverage. This type of tip comes in different sizes. The larger size acts the same as the small one, but with an even greater range.
A large round rubber tip is used to start pressing out large dents.

A plastic conical (pointed) tip works well on body lines (stiffeners, edges). The pointed plastic tip, if pressed too hard, can crush the metal and create a raised area, but will not damage the paint, unlike metal. That is, the likelihood of straightening the “edge” of the body increases before you damage the paint. Plastic can vary in rigidity and have different effects on metal. Stiffer plastics can be used on both aluminum and steel panels. Softer plastic will not be able to dent an aluminum panel with sufficient force, since this requires a stronger force than steel. With strong pressure, a sharp tip made of soft plastic may lose its shape and the pressure will not be clear; a harder material retains its shape and provides a clear, strong pressure.
Sharp metal tip. Its location is easier to determine from the back of the panel, as it gives a clear point effect. When using a sharp metal tip, you need to clearly know what you are doing. This type of tip cannot be pressed randomly onto the metal, as this will create many sharp peaks. The sharp tips can become dull over time, so you can adjust their shape yourself, if necessary.
Slightly tapered tip. It is best suited for small dents. Its shape will give you precision but little leverage.
The tip is cone-shaped with a rounded center. This tip provides sufficient force and is quite accurate.

Roller Rod Tips allow you to apply more pressure to the panel without leaving a raised area, thereby increasing the visibility of the tip from the back of the panel. Wider rollers allow you to straighten larger and deeper dents with less tendency to tear the paint or stretch the dent. A roller tip with a thinner profile is used for finishing the panel. These tips can have different hardness, as they are made of hard or soft plastic.

Types of reverse hammer

Punchers (cores, cue balls)

A punch (also called a core or cue ball, English knockdown tool) is an essential PDR tool. You will use it regularly. Most high-quality craftsmen can boast that they limit the use of a punch, but there is not a single craftsman who could do without it.

With paintless repair, dents are not just sharply straightened out from the impact on them, they are slowly and methodically squeezed out with hundreds of tiny pressures. Sometimes the pressure on the metal is past where it should be. This can be accidental, and sometimes even on purpose. This creates hills that need to be removed with a punch. The tip of the punch is located directly at the high point and lowers it down by hitting the PDR punch with a hammer or other light object.

On some dents, it is necessary to tap the raised areas around their perimeter to relieve stress and soften the metal before straightening the metal begins.

Punchers can be made of different materials and also differ in the shape of the tip. They can be blunt, sharp, rounded, or mushroom-shaped. The sharpness of the tip depends on the size and shape of the hills. Tapping with a heavier punch (such as steel) with a soft, rounded tip will take much less time to move the same amount of metal than tapping with a lighter nylon punch. A lighter punch requires much more hammering or striking force to create the same impact as a heavier punch.

The type and material of the hammer used to strike the punch does not matter much; what is important is its weight, which will affect the force of the blow. In addition to the hammer, you can use other objects if it is more convenient for the master.

It is recommended to purchase one punch with replaceable tips.

In general, to tap high spots during dent repair, either a punch or a special hammer without using a punch can be used. So-called blending hammers are best used for larger, softer high points. Punchers are generally best suited for sharper elevations.

Manufacturers. Who to give preference to?

1. Makita jackhammer. This brand is in great demand in the building materials market because it has an excellent reputation. Each unit of production is characterized by Japanese precision, high quality, and practicality. The pricing policy is acceptable.

The Makita jackhammer is produced by the company in a wide range; in the model range you can find custom and professional, light, medium and heavy, as well as electric, pneumatic and gasoline chippers.

In the “Custom Jackhammer” group, I would like to highlight the Makita HK 0500 (HK0500) SDS-plus model. Its technical characteristics are amazing: weight - 3100 grams, length - 46.8 cm, while the impact force is 2.8 Joules, and the number of blows in 60 seconds is 2000-3500.

In the line of professional models, Makita HM 1203 C (HM1203C) SDS-MAX and Makita HM 1304 B (HM1304B) 28.6 mm deserve special attention. These models optimally combine parameters such as weight, force and impact frequency.

2. Bosch jackhammer. German quality has long been valued all over the world, and the quality characteristics of this category of products are no exception.

It is worth noting that this quality is expensive, but quickly pays off. One of the best professional hammers of this brand is the BOSCH GSH 27 model.

3. Jackhammer "Interskol". Produced on the territory of the Russian Federation. The model range includes many positions. The company demonstrates the ideal price-quality ratio of its products.

What kind of device is this

If you are at least a little familiar with plumbing, then creating such a tool at home will be quite simple for you.

Making such a device yourself will not take much time, and will not even require special equipment or knowledge. For a more visual understanding, we present a primitive drawing that will not be superfluous.

As noted above, the design of such a hammer is very simple. A metal sleeve is mounted on a steel rod 50 cm long with a diameter of 10 to 20 mm, which should be easy to grip by hand.

The diameter of its hole should allow it to slide freely along the hammer rod without creating a large backlash. A handle is installed on the top to hold the tool by hand. An impact washer is tightly attached to the rod in front of the handle.

You can find out how to choose a screwdriver here.

And this article will tell you how to choose the right electric spray gun.

Another safety washer is attached at the bottom, which prevents the bushing from flying off the rod during operation, thereby causing additional damage to the leveled surface. And at the very tip of the tool there should be a hook for grabbing staples.

If you decide to make such a hammer yourself, rather than buy it in a store, where the price will be much higher, then it is advisable that the hook and bottom washer be removable. Because for convenience when working, it is better to have a set of hooks of different lengths, as well as several bushings of different weights.

Application, operation

The main areas of use for jackhammers include construction and mining.

In the first case, they are used to dismantle structures during redevelopment and demolition, cutting metal, removing concrete and asphalt road surfaces, compacting soil in hard-to-reach places, constructing wells, loosening frozen soils, making holes and niches, and removing ice.

In the mining industry, jackhammers are used when more powerful equipment is not available. Thus, the conditions of use in mines, which primarily consist of limited space, determine the need for tools of compact sizes. In addition, workings are processed along the entire radius. Therefore, a lightweight hammer is required that can be used upside down.

The scope of application is largely determined by the type of device: in what conditions and in what atmosphere to work, etc.

Some features of the operation of jackhammers were noted above. Regardless of the type of device, there are general rules. Firstly, before starting work, you should lubricate the tip of the nozzle with any plastic lubricant such as lithol and grease. Secondly, it is recommended to add lubricant to the tool barrel when working at least twice a shift in order to extend its service life. In this case, use various oils for the jackhammer in accordance with the instructions. Some recommend I20A, others recommend 15W-40 gear oil, etc. Thirdly, you should prevent dirt and water from getting into the device, rinse the lubricant cartridge with gasoline after completion of work, having first removed the nozzle. Fourthly, it is necessary to follow the instructions, using the hammer-breaker for its intended purpose and without overload. Fifthly, it is recommended to carry out maintenance once a month, which includes complete disassembly and washing of all parts with gasoline or kerosene.

In addition, there are specific operating features for each type of jackhammer.

Thus, after a long break, before starting work, it is recommended to disassemble a pneumatic hammer and wash it thoroughly with gasoline. Then, for two weeks, the barrel should be lubricated with pneumatic oil 3 to 4 times per shift.

For electric models, timely replacement of brushes is necessary. In addition, technological breaks of 10–15 minutes should be taken at intervals of 25 minutes to avoid overload.

On gasoline jackhammers, it is necessary to first prepare a fuel mixture, including gasoline and oil, of a certain concentration. The instructions indicate what kind of oil to pour into the jackhammer, in what quantity, etc. Moreover, it is necessary to completely exhaust the fuel mixture or drain the remainder. This avoids contamination of the battery with an oil film.

Each type of device under consideration is characterized by specific faults.

The main cause of breakdowns of electric jackhammers is a violation of the electrical circuit, which consists in the breakdown of the button and the erasure of the brushes transmitting electricity to the motor. Replacing brushes is very simple. Repairing the button is more complicated due to the fact that in many cases it is necessary to disassemble the entire case, however, on modern models, taking into account this feature, it is equipped with a separate cover to simplify replacement.

For models with internal combustion engines, carburetor clogging is typical. Finally, on any jackhammer, jamming of the nozzle in the chuck occurs. In this case, dismantle the cartridge and squeeze out the nozzle, after which the cartridge is washed from lubricant with kerosene.

Kinds

Several parameters are used to classify the devices under consideration.

Based on performance, jackhammers are differentiated into three types.

Lightweight options are designed for household work. They are capable of crushing plaster, tiles, etc., which makes them suitable for home repairs. The weight of such mini jackhammers is 5-6 kg.
Medium power devices are suitable for asphalt, so they are used in some construction work. Weight from 6 to 10 kg provides the possibility of long-term horizontal holding.
In industry and in the construction of buildings, high-power jackhammers weighing 15-30 kg are used.

However, mass is an indirect indicator of performance. There is a classification close to the above, based on other, more significant parameters. It also includes four types.

The first includes jackhammers with impact energy up to 30 J and frequency up to 45 Hz. They are suitable for medium-strength materials such as asphalt, brick, clay, and work in confined spaces.
The second type is represented by options with an impact energy of 40 J and a frequency of 34 Hz, used in general construction work.
The third type includes models with impact energy up to 45 J and frequency up to 20 Hz. They are used for work with vertical impacts on durable materials.
The fourth type is represented by hammers with an impact energy of more than 50 J and a frequency of up to 24 Hz. Such devices are used for high-strength materials.

Based on the power source, there are four types of jackhammers.

Pneumatic devices are the most common type. The power source for them is a compressor. The principle of operation is based on the pressure of compressed air molecules on the chisel. This equipment is suitable for destroying any structures made of brick and concrete. For household options, a power of 5 J is required, while for industrial models this parameter ranges from 10 to 100 J. This is enough to destroy asphalt, stone, concrete, etc.
Electric hammers are powered from the mains. The principle of their operation is to drive the striker through the rotational element of the electric motor. Performance parameters are up to 1700 W of power, 45 J of impact energy and 2000 beats per minute of frequency. Thus, these types of jackhammers have high impact power, but are not suitable for cutting and drilling materials.
Gasoline devices are driven by an internal combustion engine, which does not have valves and a shaft. With low power, the main advantage of these options is autonomy, that is, the ability to be used anywhere. This is due to the absence of the need to connect to an energy source. The duration of operation is determined only by the amount of fuel. In addition, jackhammers of this type are considered safer in comparison with analogues. However, they have a high noise level. These models are used in the mining industry for the destruction of concrete, asphalt, and frozen soil.
Hydraulic hammers use a variety of power sources. They are usually used in emergency rescue operations.

Volumetric devices are driven by rapidly expanding air in the chamber.
The operation of turbine options is ensured by the energy generated by the rotation of the turbine.

The simplest classification of jackhammers based on a set of basic parameters differentiates them into professional and household.

Concrete breakers are distinguished by their large size, weight and productivity. These devices are designed for vertical and inclined work with concrete slabs, rocks, asphalt pavement, and frozen soils. Rotary hammers are usually more compact than jackhammers or similar in size, they are distinguished by greater accuracy and the ability to perform the functions of a drill and screwdriver with adjustable speed and reverse. This versatility makes them much better suited for household work. Thus, the operating instructions for PE-2520M indicate the possibility of its use as both a jackhammer and a drill.

Reverse hammer for body repair

No car is insured against various damages as a result of an accident. With some knowledge and experience, you can cope with some of them yourself. But sometimes you simply cannot do without qualified help from specialists. Professionals have to level out dents on cars quite often, and therefore every car repair shop must have a reverse hammer for body repair. The base of the device is a steel rod with a diameter of 20 mm and a length of 500 mm. A bushing (weight) is put on the rod on one side, and a washer is welded on the other. The washer is necessary so that the bushing does not fly out from the base, and the impact force is not transferred to the rod. The tool often comes with several special hook grips. They grab the brackets that are welded to the body. To remove elongated edges and dents, several washers are welded to the surface at once by inserting a metal rod through the holes.

The operating principle of this device is simple, but it requires a certain skill of the master:

first you need to carefully examine the damaged area of the body;
those areas that are to be pulled out must be cleaned down to the metal itself and repair washers welded to it;
then you need to hook the hook onto the washer attached to the body of the machine and, with gentle blows, pull out the dent;
the previous operation is repeated until the body is completely leveled.

Reverse Vacuum Hammer

One of the most popular and frequently used varieties of this device is a reverse vacuum hammer. It is actively used if the car is not planned to be painted in the future. Its main advantage is that it can be used to repair even large areas of the body. The weight of the tool is about 1 kg, and therefore working with it will not require much effort.

During operation, in order to properly cling to the metal, you do not have to drill even the smallest holes in the existing dent, as is done according to the standard method.

The vacuum device can work with pistons of any configuration, size and shape. The vacuum suction cup holds the material firmly while pulling out the dent.

note

Its use reduces labor costs by an order of magnitude and significantly reduces the time of work.

Stages of body restoration using vacuum modification of the device:

thorough degreasing and heating of the car surface at the site of damage;
gluing 2 special glue pins along the edges and in the center of the dent;
carefully engaging the piston and applying a vacuum hammer to the defective area (here it is necessary to control the lifting of the concave metal);
repeating the two previous stages until the damage becomes invisible;
careful finishing of the body surface with a mini-lifter and hooks.

PDR Tools

The first teams of PDR specialists began to form in the quality control departments of auto giants. They needed to create the necessary tools to successfully straighten out the small dents that were sometimes created during the manufacturing and assembly of automobiles. Initially these instruments were homemade. They were converted from existing tools of “tinsmiths”, and also invented new unique devices and improved them over time. You can read in more detail about the emergence of paintless dent repair technology in the article “history of the emergence of PDR technology.”

Homemade paintless dent repair tools were used many years ago by the early PDR technicians.
PDR technology has improved significantly over the past 15 years. Nowadays, qualified PDR technicians can straighten quite complex dents without painting. This is possible thanks to the range of modern tools, as well as the elasticity of modern paint coatings.

There are now many manufacturers that provide a wide range of paintless dent repair tools and accessories.

PDR tools can be classified by design and by application (intended purpose).

By design, instruments can differ in bend (single, double, triple bend, or more complex shapes), tip shape, length, tool diameter, shape and configuration of the handle.

By application, tools can be classified depending on which body panels they are used on or what action they perform. For example, classic hooks (or rods, from the English rod) are designed to work in open, fairly accessible places, such as fenders, roofs, trunks, hoods. They work by applying pressure to the back of the dent. Another example is the whale tail tool. This tool, in contrast to classic hooks, is used in hard-to-reach narrow places and works due to the twisting action. Additionally, PDR technicians use special reflective panels to accurately “read” dents, LED lights, and an adhesive system to pull out dents. Correcting different dents may require the use of multiple tools. The more tools you have at your disposal, the more freedom and flexibility you will have to repair a specific dent.

Next, we will look in order at the various tools that are used for paintless dent repair, as well as the necessary accessories.

Design

The design features of the tool are quite simple. A reverse hammer is presented in the form of a steel rod about 50 cm long and 20 mm in diameter. The metal base contains a locking washer, a hook and loose weights. Depending on the nature of the instrument, the latter may differ in weight.

Modern models are equipped with several types of hooks that allow you to grab metal in the area of damaged areas of the body. Proper selection of tools makes it possible to cope with quite serious work, from leveling crumpled thresholds to processing double metal, which is located in the area of the rear wings of the car.

Pneumatic suction cup puller

The pneumatic suction cup is sold in a set with several suction cups of different sizes (usually three). Depending on the size, it can create different pulling forces.

It is attached to the rods of a sliding reverse action hammer. The suction cup is made of rubber and plastic. The suction cup can work with both metal panels and plastic bumpers.

This tool can remove large dents very quickly. Used at the initial stage of repair, to eliminate the bulk of dents.

How to use

The operating principle of the reverse hammer is as follows:

First of all, you should inspect the damaged area of the car, select the appropriate hook based on the location and main dimensions of the dent, in order to then correctly calculate the accuracy of the applied force.
Then the repaired area of the body surface must be thoroughly cleaned from excess paint layer and primer down to the metal.
Next, you need to weld special repair brackets (washers) onto the metal surface of the dent using a welding machine. If the electric spotter comes complete with a reverse hammer, then during the leveling process you only need to change the nozzle.
Then you need to hook the hook of the auto tool onto the brackets, and then begin to pull out the dent with gentle and light blows.
It is recommended to perform leveling until the damaged part of the body surface is completely eliminated.
To get rid of dents on your car, you first need to weld some brackets and push a hammer through their holes to remove the damage.
After which the corrected surface defect should be treated with a primer and re-coated with paint to match the body.

However, it is worth paying attention to the fact that such a device has its drawbacks, due to which, along with the dent on the car body, a layer of paint that was not even damaged is completely removed. In addition, areas of extensive dents in the hood, roof and surface of the trunk of a car cannot be straightened with its help.

Welding staples can greatly deform the metal, which will ultimately lead to a complete replacement of the part.

PDR lighting

Lighting and reflection is one of the most important components of a PDR repair. PDR lamps are used indoors and allow a specialist to see dents on car body panels in more detail. There are two types of lighting currently in use: fluorescent and LED. With the introduction of LED lighting, things have definitely changed. LEDs allow you to have more compact, lightweight and very durable lamps. LED panels can change the light intensity, and even color. This is necessary for cars of different colors. For example, light-colored panels may be difficult to repair without painting using a standard white light PDR lamp.

Lamps for PDR repair may contain a special light diffuser. Usually these are parallel lines or the so-called fog board. The color and design used on the face of the lamp is the personal preference of the artist. Such diffusers or screens can be purchased separately and placed on the lamp or replaced with an existing diffuser. They help achieve high detail defects.

Reflective screens (reflective screens/panels) are a panel with a specific pattern (usually parallel lines). They, unlike a special lamp with lines, do not produce their own light, but reflect existing light (for example, sunlight) and cast lines onto the panel being repaired, helping to better see the damage.

So the purpose of the PDR light (or reflective screen) is to allow the technician to see the damage pattern that is happening inside the dent. By reading shadows and distorted reflections, a specialist can determine where the metal is high and where it is low. The craftsman also uses reflection to guide the tip of the tool exactly where it should be. Further, the reflection helps to monitor the repair process, allows you to develop precise force and stop pressing in time. After manipulating with the PDR tools, once the distorted lines become parallel in the panel reflection, the dent will be successfully corrected.

PDR lamps come in different sizes and variations. In general, they can be divided into stationary lamps for workshops and portable ones.

Stationary lamps are mounted on collapsible tripods, allowing you to work with large volumes of damage. They can rotate and can be installed at any angle. These lamps are useful for repairing hail damage and can illuminate the entire roof or other panels.
Portable PDR lamps usually range from 25 cm to 50 cm in length. They are easy to move and are usually mounted on the car using a suction cup. Mobile lamps are designed to work both in stationary conditions and on the road. They allow you to work with minor damage and damage of medium complexity.

When choosing a PDR lamp, consider the following factors:

Size
Ease of installation and setup
Personalization (can you change the light intensity, color)
Battery life (in the case of a portable lamp)
Durability

Criteria for choosing a hammer

The high energy content and the fairly large mass of individual devices force us to pay attention not only to the purely technical characteristics of jackhammers. They also evaluate such non-obvious factors as ergonomics and layout.

Impact energy

As mentioned above, it is not recommended to use jackhammers to destroy reinforced concrete or cement monoliths with a low sand content in the solution. Carrying out such work will not only lead to low productivity, but will also cause high wear and tear, and, consequently, the need to spend money on repairs.

You need to choose the optimal model according to the manufacturer’s recommendations. If you need to get a guaranteed result, it is recommended to explore thematic forums or ask for advice from experienced builders.

Weight and dimensions

Estimating the weight of a jackhammer and the size of the device is a highly individual process. The tool is selected based on habits, operating mode (time of activity - rest), and usual indicators of free space for manipulation

However, you should pay attention to the weight distribution of the device. The closer the center of gravity is to the leading hand, the less fatigue accumulates during the necessary movements of the tool

Materials

All materials in the design of the device must be as strong and reliable as possible. The use of plastic is not allowed for gearbox elements. But some manufacturers don't know about this. Therefore, each product should be examined as carefully as possible before purchasing, so as not to encounter breakdowns literally in the first hour of operation. The main thing is that you should not skimp on tools from reliable brands.

Ergonomics

The design of the jackhammer should ensure zero deflection of the tool axis upon impact and ensure that it is held in the hand as rigidly as possible.

The hammer handle should have a straight section at the grip point.
The grip zone should be located on the axis of application of the impact impulse.
If the tool has two handles (heavy ones, concrete breakers), they should be located on the same line, perpendicular to the axis of impact, with hand grips at an equal distance from the center.

Any handle has a start button. The location of this element must be such that pressing or switching does not require a loosening of the grip. The same applies to any regulatory bodies. None of them should cause the need to shift attention or change the mechanics of operating the instrument.

Which tool should I choose to repair a specific dent?

Tools come in different lengths, shapes and sizes. Each tool is uniquely designed for a specific purpose, and a PDR technician has a variety of tools to access even the most difficult to reach areas of the vehicle.

How do you know which tool to use for a certain dent? There are two main things to consider, one is “reach” and the other is “leverage”. That is, whether you can reach the back of the dent and whether you can influence it. This will help narrow down your choices among the available tools.

It really doesn't matter what tool you use, the main thing is to get the result. There may be more than one way to repair the same damage. In addition to the classic PDR hand tools, do not forget about the capabilities of the adhesive system. With its improvement, the possibilities of paintless dent repair have expanded significantly.

Vacuum dent removal

If a dent has formed on the body (door, fender, roof), but the paintwork has not been damaged, you can correct the defect using vacuum straightening. To straighten dents, a pneumatic or vacuum tool (suction cups) is used; this method is used to straighten so-called “poppers” measuring more than 15-20 cm in diameter.

The advantage of this method is that after correcting the defect, painting is not required - the paintwork is not damaged, and the work is completed much faster than with conventional straightening. But vacuum dent extraction requires a certain amount of skill, and not every dent can be straightened out.

Advantages and disadvantages

The reverse action hammer has many advantages over tools of a similar nature. It allows you to quickly perform straightening without significant structural changes to the car. Work with this tool can be done in places that are inaccessible to work with a conventional tool. Also, the cost of such a tool is relatively small; almost any car enthusiast can purchase such a tool for his garage. Also, in most cases, you can do without destroying the factory paint.

The only disadvantage of this tool is that complex damage cannot always be corrected. Also, in some cases, a person without experience can only cause more damage to the car body.

Overall, this is a great tool to have in your toolbox as it can quickly correct mistakes made by the driver or those around you.

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One of the indispensable tools for straightening a car is a reverse hammer for body repair. Its purpose is to straighten small dents on pillars, sills, arches, i.e. in areas where there is no access from inside the body. This device will be discussed in this article. First, let's tell you what this device looks like.