- Arts and Design
How Do I Build a Power Hammer
Power Hammer You Can Build
What Do You Need To Know To Build a Power Hammer
I am sure this question keeps you awake at night.
If you work as a blacksmith, even part time you probably wish you had a way of using a machine to help with the work. Blacksmithing is a physical activity. There is no way of getting around it. A power hammer will reduce the wear and tear on your joints and can prolong your career. As far as blacksmith tools go a power hammer is one of the most important.
All a power hammer really is, is a heavy weight that moves up and down. The speed and force of this up and down motion is usually controled by a foot peddle of some sort.
If you are building a power hammer you have a couple of options to derive the power from. Mechanical and air pressure.
Mechanical Power Hammer
To build a mechanical power hammer the basis of the motion is a rotating crankshaft with a counter weight near to the weight of the hammerhead. This crankshaft is driven by a motor or an engine with some form of slip clutch controled by a foot peddle.
The rest of the machine is the frame, the anvil, and the hammer dies themselves. The frame has been constructed by many different materials and many different configurations. The best I have found is using square tubing. You need something that is strong and ridgid at the same time. In times past power hammer frames where constructed of cast steel.
The anvil needs to be solid steel and at least 10 to 1 ratio of the hammer head weight. Depending on the size of the power hammer it can be welded to the frame or if very large then it should be on a separate deep foundation.
The dies are made of tool steel and may come many different configurations depending on the use that you put your machine to. For me flat slightly crowned dies work the best.
The other important part of a mechanical power hammer is the connection of the hammer head to the crank shaft. This connection must be flexible and spring loaded to take the shock of the impact. As you work your bar under the power hammer it will change size and you need a way to compensate for this and still apply force to the metal.
There have been several systems developed over the years that do this very well. Most use a toggle and spring system. Without this flexibility your hammer will break from the force exerted on the crank shaft.
Air Power Hammer
The other practical option that you have is to build an air hammer. The driving force behind and air hammer is the air pressure. You still require the same frame and anvil set up but with air you have a built in cushion in the hammer head so you don't have to worry about messy springs and linkages.
The air hammer uses a feed back circuit to shuttle a main spool valve back and forth. This spool valve shunts air from one side of the cylinder to the other. More air pressure on one side means movement up or down.
The control circutry are basically switches that tell it to go up and down. All this is controlled by a foot peddle that exhausts a variable amount of air. The amount of air exhausted on the power hammer, controls the force and the speed of the hammer head.
With a bit of work you can build a very accurate and finely tuned power hammer. Over the years I have mostly built air hammers and have made a set of plans that will help you make your first one.
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If you are interested in other blacksmithing tools please visit my Blacksmithing Tools page.