Blacksmith power hammers or trip hammers
If you have ever worked with a mechanical hammer, you will see the world of blacksmithing with different eyes. Hydraulic hammers really fall into 3 basic categories, hydraulic presses, power hammers, and jackhammers. They are all designed to increase the amount of force you can apply to steel. This means you can get more work done in a given amount of time and you can work with a bigger bar. Suddenly this opens up a whole new creative reality with steel.
Hydraulic Presses
I don’t use one in my shop, but have used one years ago at another blacksmith shop. Hydraulics have tons of power (literally) and can force metal into many different shapes very effectively. They are useful for extreme controlled force applications, such as forcing steel into preformed dies, or cutting to specific lengths or angles, etc.
This is not an impact machine like jackhammers or jackhammers, and it’s not fast. It can be used to mine steel, but this is tedious. Although it would save time drawing by hand and allow you to work with a larger bar, it would drive me crazy with the slow process.
Essentially, the machine is a frame-mounted hydraulic ram with an electric pump. You use a foot control to smash metal. Step with the foot apply more force. Release your foot from the dies, then you can move the bar and apply the force again in a different place.
There are a couple of positive aspects of a hydraulic press. They take up little space and do not require a special foundation. Prices are manageable for this type of tool. Around $2000.00 in my area. There is no impact noise or vibration with this type of machine. The hum of the hydraulic pump may be loud but it doesn’t have the same nuisance factor for neighbors as the impact of a hammer. Presses are rated by the number of tons of pressure the ram can produce. 20 tons, 40 tons and 60 tons are common sizes.
mechanical hammers
All power hammers work on a variation of the same principle. A rotating crankshaft lifts the counterweighted hammer head, then pushes it down for the next half revolution. The attachment on the other hammer head has to be a spring construction of some kind so that the shock is absorbed by the spring and not the crankshaft. The counterweight relieves some of the stress on the motor.
There have been many different configurations of power hammers over the years. Little Giant comes to mind, but this is just one style. Others include Helve hammers, etc. Power hammers are classified based on the head rate of the hammer. So a 25lb Little Giant has a hammerhead weight of 25lbs. The greater the weight of the head, the more steel you can work under it, but the more motor you need to run it.
Something to think about. If your shop is outdoors but you don’t have electricity, you could run a power hammer with a small gasoline engine. A bit pricey, but compared to the amount of work you could do this way, it might be worth it.
I’ve only done a little work with power hammers, but a 1 hp motor will work with a hammer head weight of about 50 lbs.
The beauty of a mechanical hammer is that it is relatively simple to build or repair. The movement concepts are very simple and easy to follow in slow motion. Power hammers were relatively common in industrial settings in the late 19th and early 20th centuries, so you may be able to find one for a good price in your area. The downside is that the parts can be impossible to find and you may have to make your own.
You can also build your own mechanical hammer. It will take some tinkering, but a good working hammer can be made quite cheaply. They don’t take up much space. Maybe 2 feet by 3 feet for a small one. They are a bit noisy to run and have an impact sound. They need a good base, although a small one can get by with a small base. They are a bit limited by the tasks you can do with them. If you are creative with your tools, you can still get a lot of work done and save your arm.
jackhammers
My personal favourite. The jackhammer was originally conceived as a steam hammer for large industrial applications. Like power hammers, they are rated by the mass of the hammer head and typically range from 50 lbs. to 1,200 lbs. or more. The higher end of the scale are massive machines that require gigantic foundations to function properly. It is poetry in motion to observe the use of an expert blacksmith.
The principle behind the jackhammer is quite simple. Air pressure lifts a weighted hammerhead, then something changes the air pressure and the hammerhead drops under the force of air pressure and then rises again. The air at the bottom of the air cylinder acts as a shock absorber replacing the springs in a mechanical hammer. This process creates a cyclic hammering of the steel. The weight of the hammer head and air pressure contribute to the force applied to the steel.
Most smaller blacksmith shops use sizes from 50 to 150 pounds. There are two subclasses of jackhammers that you should be aware of. The autonomous version and the air compressor version. The self-contained uses two air cylinders. One is the compressor cylinder and is driven by a motor. This cylinder supplies air to the hammer head cylinder. Therefore, each upstroke of the drive cylinder pushes down on the hammerhead cylinder and each downstroke pushes up on the hammerhead cylinder. The valve causes air to be exhausted or sent in varying amounts to the hammer head cylinder. This provides control of the stroke and force applied to the steel. This cyclic timing is governed by the speed of the electric motor.
The air compressor that connects the jackhammer is powered by constant line pressure and has a feedback loop built into the design. The hammer head goes up and activates a switch that tells it to go back down. Once you reach a certain point of travel, another switch tells you to go back up. The amount of exhaust dictates both the speed and the force applied to the steel.
Although jackhammers appear to be a bit more complicated than a power hammer, there are actually fewer moving parts and fewer parts to wear out. I find them more versatile. You can adjust your stroke and strength simply by toning down your pedal. With a mechanical hammer, you have to make a mechanical adjustment to change the height of your blow. Its force is controlled by the speed of the impact or the speed of rotation.