Metal Shaping Fundamentals
By Eddie Paul(Excerpted from his book “Eddie Paul’s Paint & Bodywork Handbook: Secrets of a Master Customizer”. For more information or to order your copy, click here. Planishing Hammer The planishing hammer…
By Eddie Paul
(Excerpted from his book "Eddie Paul’s Paint & Bodywork Handbook: Secrets of a Master Customizer". For more information or to order your copy, click here.
Planishing Hammer
The planishing hammer and English wheel are two tools that look somewhat alike and are often confused with each other. Of the two, the most commonly used is the English wheel. It is ideal for rolling a sheet of steel or aluminum into a particular shape, such as for a fender or motorcycle gas tank. But the hammer has its applications which differ from the wheel in very distinct ways.
Since the planishing hammer is one of the tools that I designed and now manufacture for The Eastwood Company, I’m able to let you in on a little secret: the planishing hammer is little more than a pneumatic rivet gun with a hammer head installed and mounted on a “C”-shaped frame with a radiused anvil mounted opposite the hammer head. The term “planishing” means to smooth up metal with gentle hammering. The concept is that the heads of the hammer and anvil will both lower the high spots and raise the low spots simultaneously as the metal is fed between them.
Planishing hammers are making a strong comeback thanks to the many “build” shows that have saturated cable TV. It seems as if a workshop is not complete without a planishing hammer and English wheel, and this is one of the main reasons that I designed a set of these tools that the average person can afford. A planishing hammer is used more for smaller areas and raising a bump or scoop in the center of a panel, while the English wheel is for reshaping a whole panel. Both tools can almost always be interchanged with the same results, but there are times when a planishing hammer will work better or faster. I sometimes use the planishing hammer with a set of damaged dies to distress a piece of metal, making it appear aged by passing it through the dies a few times at random speed and direction. It works like nothing else to give a random pattern of flaws to an otherwise perfect sheet of metal. I used to use a pneumatic hammer by hand against a sandbag to shape scoops on cars, and this worked fairly well, but it does not compare to the planishing hammer mounted on a stand. The stand mount keeps both your hands free for holding the metal as you hammer. The dies, which can be custom made for special jobs, will determine the final radius of the shape.
The combination of a hammer and a wheel is an unbeatable duo for the garage or small shop. A fun project you may want to try that will get you used to the hammer is to make some medieval armor, like a helmet, breastplate or even a shield. That kind of stuff is fun to make and will also dress up your shop with a piece of art that your friends can see and when they ask who made it, you can proudly say “I made that, just for fun!”
English Wheel
Metal can be shaped in many different ways. Some methods involve single bends, some involve more difficult compound bends in which the metal is bent in two different directions at the same time, creating a convex or concave shape. Older automotive fenders such as our 1940 Ford are prime examples of the compound curve. The compound curve provides an enhanced appearance with smooth flowing lines and the metal has more strength, due in part to the shape and the fact that the metal has been work-hardened.
An English wheel and a few supplementary tools to rough the metal into shape are all you really need to make compound bends. These tools include a sandbag, a few shaping hammers, a shrinker and a stretcher. If you follow along with the accompanying photos, we will try to cover the basic concept of shaping metal with a few exercises that will show the principles of the English wheel.
We will start with some 12-inch squares of 3003-H14, half-hard aluminum, 0.063 inches thick. You can wheel either steel or aluminum but we are using aluminum in this example for its ease of shaping and its ability to anneal with a simple torch. On most cars you will be shaping steel and the process is essentially the same, but aluminum is good for practice.
Many people get the English wheel and the planishing hammer confused with each other, and for good reason. The biggest difference is that the planishing hammer allows you to work smaller areas than the English wheel does and the hammer is an air-powered tool. Like a planishing hammer, the English wheel can be used for smoothing out a small wrinkle in a panel or creating a curve or raised section in a piece of metal (aluminum or steel). Where the English wheel excels is in working with larger panels, either adding contour or smoothing welds or slight imperfections. It is the perfect tool to follow up a mallet and sandbag to help smooth out the rough shaping of a part. These two tools will turn the average hobby workshop into a professional metal worker’s shop.
English wheels come in a variety of sizes, but for the weekend fabricator, I recommend a smaller benchtop size. One of the handiest wheels is the one that I designed for The Eastwood Company. It’s large enough to handle most jobs yet small enough to fit on a workbench to make anything from hood scoops, fender skirts, motorcycle fenders or even a motorcycle gas tank. One thing that sets my version of the tool apart from others is that it can be ordered as a set with a planishing hammer. Together, these tools will enable you to customize almost any part of a car body.
English Wheel Techniques
This English wheel frame is constructed from sturdy 2-inch mild steel tubing that is mandrel-bent into a gentle curve, allowing space for your work piece due to the
22-inch throat depth. We have also included three of the most common anvil wheels, ranging from flat to medium crown. The solid steel rollers are fitted with bronze bearings for trouble-free extended operation. The wheel is also designed to be portable and easy to set up, so it can be stored away after each use if necessary.
The most unique feature of the tool that I designed is that it is convertible! This is the only tool on the market that can be converted from an English wheel into a planishing hammer within minutes utilizing the same frame. An English wheel’s value, like most metal-working tools, improves with operator experience. I suggest that you practice on clean scrap metal before working on your project.
The English wheel frame should be securely mounted at a comfortable height to work with. We have found that instead of standing while using the tool, it’s nice to use a rolling stool to help keep the metal at a comfortable working height. This is a personal choice and there is no one correct height for all people, so try different heights until you find the one that is comfortable for you.
The tool can also be bolted to a workbench. If a pedestal stand is used, it must be bolted to the floor to keep the wheel from walking away because of the pushing and pulling of the metal being shaped. We have also designed a channel that will hold both the planishing hammer and English wheel on a common stand. This channel also holds the extra wheels and anvils.
Keep the area clean and neat.
Keeping the work are neat and clean is important. Organize and relocate your tools while putting away the tools you don’t need. An organized area is much more conducive to productivity and a better-looking, finished project.
Keep the metal clean and deburred.
Having clean metal is crucial. It does more than make you look professional, it makes you professional. Constantly wiping the metal and wheels down will eliminate dirt or other foreign objects from getting between the wheel and metal and leaving imperfections on the finished work. A single piece of dirt on one of the wheels can leave hundreds of indentations in a sheet of metal before it is discovered. Get in the habit of wiping down the wheels.
Keep checking your progress against the form or project.
Wheel lightly and check often so you don’t over-shape an area. Constantly check for fit on the metal and get in the habit of guessing how much wheeling will produce a particular amount of curve. Wheeling is about 80 percent skill and 20 percent muscle. Success comes from getting a “feel” for the tool and the metal.
Less is better than more.
It is easy to over-wheel a part, rendering it scrap or at least more difficult to repair. Less is better than more when wheeling, so take light rolls not heavy rolls. It seems that turning the bottom wheel tighter will save time, but it will only crease the metal, giving you more work. Take it easy and don’t overdo it.
Slow your roll to acquire the skill.
Another skill that will come with time is the art of moving the metal back and forth and turning it just the right direction and just the right amount for the reverse run. The best way to gain this skill is to start out very slowly and get the motion down as you increase your speed. This will take practice, but it will become second nature with time.
Mark the metal to show how to roll.
Don’t be afraid to mark the metal as to where you want to roll a high crown and where you want a reverse crown (this should be marked on the backside of the sheet). After you roll the sheet and check it, wipe it down to remove the marks and remark it as needed. This will help you keep track of the progress.
Change the roller to change the curve.
Our company sells a tool that will help you figure out which bottom wheel you need to match a curve. This tool is to be used as a reference only and is not an exact template. The curve or shape can be changed if you under-roll or over-roll an area. But the template will help get you the general shape you need, the rest is up to you.
Practice with aluminum.
It is the easiest metal to work with and will teach you the basics with less effort than steel. Later, you can apply your newly learned skill on auto body sheet metal. The best alloy of aluminum is 3003 H14, half-hard aluminum 0.063 inches thick. Other alloys can be used, but this grade is the best for welding and working.
Keep the metal dry or it will attract dust and dirt.
With every move of the English wheel, the metal is stretched a little bit over the lower wheel crown, creating the curved shape. Therefore, the more curve there is in the lower wheels, the more curve you add to the metal being shaped. The flatter the crown of a lower wheel equals less curve. Try not to over-work an area. Removing a high crown is not as easy as putting one in. Work slowly and double-check your progress often, especially if you are making a body panel.
Basic tracking.
The usual grip on metal being shaped is thumb on top, hands at both sides in a position near the rear of the panel if shaping a smaller part. If shaping a larger part, your hands should be near the center or point of balance.
There are three points of entry for inserting the metal panel between the wheels: front, side and open. The frontal entry method is used when you already have a set wheel pressure that you do not want to change. Simply place the metal to be shaped between the two wheels and push forward slowly but firmly and don’t force it. Too much pressure and you might ruin the metal by crumpling or folding it. Entering from the side with a pre-determined pressure on the wheels is ideal when working on spots near the edge of the metal. Set the metal alongside the wheels at a slight angle. As the metal enters you will feel the wheels take hold. Continue for 1/2-inch into the metal, or to the problem area and straighten the piece so it runs parallel to the wheels. Further tracking will stretch the edge.
The open method is the most common entry. With the wheels adjusted far enough apart to insert the sheet of metal, place the metal with the position to be worked between the wheels. Now add pressure and begin working the metal. This method is also ideal when an area to be worked is located towards the middle of a panel.
We’ll start with a basic example. The ideal tracking path is a series of tight zigzags spaced about 3/8-inch apart. Start at one corner and slowly work the metal back and forth until you reach the end. Now try going in reverse of the pattern you made by tracking the metal back to the starting point using the same zigzag pattern.
Cross-wheeling the metal is exactly as we described earlier, but with the piece turned 90 degrees. This is the essence of shaping with the English wheel. You should refrain from rotating the metal being shaped while between the wheels as they will mark up your work.
If all the tracks in a tracking pattern end up on the same line, the effect is very noticeable. Instead of a smooth blend from one shape to another, there is an abrupt transition. This can be dealt with by the “staggered stop” method. This technique uses two different stop points for the track lines as can be seen on the example. Note the alteration of the stops between different tracks as the metal is shaped. This is done during the 90-degree cross-wheeling as well. This method blends the newly raised metal and the old shape much smoother, producing better results. On some larger projects you may have three or more stop points in order to create the desired shape.
The previous examples show how to raise the metal. Now let’s look at a way to remove the raised effect. Using the same light pressure as before, enter the metal into the wheels from one side. Track along the edge three times, then inboard for 1 1/2 inches using the 3/8-inch tracking method as indicated in the example. When reaching the end of the pass, track back outboard, omitting the edge tracking.
Treating all four edges this way removes much of the shape that was raised by the earlier examples. If the shape has not lessened much, try increasing the pressure a little and try again. Should your pressure be too high, the edge will take on a wavy appearance during the edge tracking. If this happens, concentrate on the inboard tracking until you have a flat edge again. If too much of the raised shape remains, try the same technique as before, but go inboard for 3 1/2 inches on all four sides.
Sometimes you will have a “soft spot” in the metal being shaped. This is detected as a slight oil can effect in your metal. When you press on the “soft spot” it will click from the front to the back side each time it is pressed. To remove imperfections like this, find the edge of the affected area and mark it with a pencil or non-permanent pen. Its position on the metal, either on the edge or in the middle, will determine how many and where the passes should be.
The accompanying examples illustrate a few different tracking paths that can be used to remove a soft spot. Note the tracking pattern has a variation; the tracks are opened up at the end of each pass, instead of the usual 3/8-inch pattern. This serves the same purpose as the “staggered stop” technique discussed earlier, which blends the new shape into the old. Also note that the passes are not required to be parallel to the edges. They can be any direction that serves the purpose at that time. Using a light wheel pressure, begin tracking next to the problem area, then away from it.
Repairing a wavy, or loose, edge requires a similar technique. Mark the area and begin tracking the edge. You should only track the length of the loose edge and not the entire length of the metal being shaped. Remember to open up your tracking as the pass ends.
