Over the years, technology has advanced toward the development of larger and faster hammers. These developments included rams that were raised by ropes through human or horse muscle, those hoisted by steam winches or powered by steam, air, or hydraulic pressure, and finally the diesel hammer. Double acting hammers were developed in order to speed up operations.
Impact pile driving hammers consist of a ram and an apparatus that allows the ram to move quickly upwards and then fall onto the driving system and pile. The ram must have a mass and impact velocity that is sufficiently large to move the pile.
A properly functioning hammer strikes the pile in quick succession. It transfers a large portion of the kinetic energy of the ram into the pile. The stroke of a pile- driving hammer is usually between three and ten feet (900 to 3000 mm).
External combustion hammers burn the fuel that provides the energy for the operation outside of the hammer itself. These hammers have external power sources such as the crane, steam boilers, air compressors, and/or hydraulic power packs. The energy moves the ram upward, and in some hammers, downward as well.
The drop hammer is the oldest type of pile driving hammer in existence. The hammer is connected to a cable that is attached to a winch on the crane. The hammer is raised to the desired stroke. The winch has a clutch on it that allows the operator to release the hammer, which falls by its own weight and strikes a pile cap and the pile.
The available energy per blow of a drop hammer is the product of the ram weight times the drop height. Standard ram weights range from 500 to 10,000 lbs (2.5 to 50 kN). Typical drop heights are approximately 4’ (1.2 m). For a given hammer, varying the drop height can vary the energy per blow. Drop hammers are typically used on very small projects and for small piling.
Advantages of Drop Hammers
Single acting air/steam hammers are essentially drop hammers, except that the hoisting cable is replaced by pressurized air or steam (motive fluid). The ram is usually a short, stocky block of steel that is connected at its top to a piston. It is guided by columns or inside guiding enclosure.
Single acting air/steam units from Vulcan and Menck are commonly used to drive piles offshore.
The operating rate of single acting air/steam hammers range between 35 and 60 blows per minute. This rate is comparable to most other hammer types that lack downward assist.
Advantages of Single Acting Air/Steam Hammers
Disadvantages of Single Acting Air/Steam Hammers
The desire to create a hammer that applies blows in rather quick succession for increased productivity led to the development of double acting air/steam hammers. For an increase in blow rate, the stroke was shortened. In order to maintain a comparable energy rating, the ram was accelerated during its down stroke using active pressure.
Advantages of Double, Differential and Compound Acting Air/Steam Hammers
Disadvantages Double, Differential and Compound Acting Air/Steam Hammers
A hydraulic hammer incorporates the use of an external energy source to lift the hammer to the top of its stroke. For the single acting hydraulic hammer, the free-falling piston develops the actual energy induced into the pile, much the same power stroke as a drop hammer or a single acting air/steam hammer.
These hammers substitute hydraulic fluid for air or steam, and it is applied to the piston to move the ram. A hydraulic power pack provides the pressurized fluid to operate the hammer. Hydraulic impact hammers can be single acting, double acting, differential acting, or other variations. Most but not all hydraulic hammers employ the use of an electric valve operated with a variable timer. The timer allows for flexible control of the output energy. Others use a purely hydraulic system to control the valve and thus the cycling of the ram. Some are powered using the hydraulic power units on the crane or excavator.
Most hydraulic hammer manufacturers claim high efficiencies for their hammers. Although there are many improvements in hydraulic hammers that enable a more efficient drop, the main reason for the higher efficiencies is that they have some kind of downward assist to equalize the hydraulic flow during the hammer cycle.
These hammers burn the fuel that powers them inside of the hammer itself. The diesel hammers are the only constituent of this class, although other types of fuel are being used.
An open-end diesel hammer consists of a long slender piston (the ram), which moves inside a cylinder. The cylinder is open at its upper end, thus allowing the ram to partially emerge from the cylinder. Since the ram falls only under gravity, the OED is also called single acting.
There are many manufacturers of open-end diesel hammers throughout the world. The hammer ratings vary from 5 to more than 300 kip-ft with ram sizes between 1 and 35 kips.
Advantages of Single Acting (Open End) Diesel Hammers
Disadvantages of Single Acting (Open End) Diesel Hammers
Upon impact, the ram pushes the impact block, hammer cushion, helmet, and pile head rapidly downward, allowing the cylinder to fall under gravity. The impact block separates from the ram within a very short time and the pressure of the combusting air-fuel mixture will cause further separation as the ram is forced upward.
A closed end diesel hammer consists of a long slender piston (the ram), which moves inside a cylinder. The cylinder is closed at its upper end, thus causing the ram to compress the air trapped between ram and cylinder top. When the ram falls, it is subject to both gravity and the pressure in the bounce chamber. For this reason, the CED is also called double acting.
There are two prominent manufacturers of closed end diesel hammers distributing their products in North America: Bermingham and MKT Geotechnical systems. The hammer ratings vary from 5 to not more than 80-kip-ft, with ram sizes between 1 and 10 kips. The MKT hammers are built using liquid fuel injection. Bermingham’s closed end models use atomized fuel injection.
Advantages of Double Acting Diesel Hammers
Disadvantages of Double Acting Diesel Hammers
You’ve heard the name, but what are benefits of STILETTO® tools? The answer boils down to three simple words: power, comfort and weight. These three features are some of the most important benefits of Stiletto tools, and you’ll recognize them as soon as you use them. Whether you need a heavy-duty hammer for rough carpentry or a lather’s hatchet that doesn’t hurt your shoulder, elbow and wrist during everyday jobs, there are plenty of options to choose from. In this Stiletto tools buying guide, you’ll learn what to look for as you shop for hammers, pry bars and other common hand tools.
Some of the brand’s most well-known products are Stiletto hammers, and they provide all three of the benefits listed above. They’re powerful, pain-free and lightweight tools, made to reduce fatigue while you work. They also reduce pain from impact shocks, and there are several things to consider as you make your selection. Four of the most important aspects are body construction, claw style, face and handle.
Weight distribution also plays a role in the performance of a hammer. A balanced tool helps you maximize the force of impact, so you get more power with every blow. The best Stiletto hammer for your shop depends on what types of jobs you want to tackle.
If you’re already comfortable with a steel hammer, you don’t have to try anything new. Stiletto offers steel hammers with classic styles that produce significant impact strength with every swing. Solid steel resists damage, so these tools retain their strength for years. The best Stiletto hammers (with steel heads) feature solid hickory handles that help absorb vibrations while you work. They are available with flat and milled faces and straight and curved handles.
Of course, the best Stiletto hammers may not feature any steel at all. Many have full titanium heads and poly fiber or hickory handles. These tools provide the most obvious benefits of Stiletto tools because they deliver as much strength as their steel counterparts with only a fraction of the weight. Titanium absorbs shock vibrations much more efficiently than steel, so you don’t lose power when the head hits its target, and these tools also minimize stress on your joints. While many other hammers recoil upon impact, titanium hammers reduce discomfort, so you don’t feel the blow with as much force.
There are plenty of reasons why you might need a claw at the end of your hammer. Whether you need to remove nails in tight spaces or pry light materials to repair a subsurface, Stiletto claw hammers give you the leverage you need for the job. These versatile edges serve different purposes. Here’s how to determine which Stiletto titanium tools to buy for your job.
Straight-claw hammers provide extra strength when pulling nails and usually have enough strength to pry light materials out of place. (These aren’t the only Stiletto titanium tools to buy for this purpose. We’ll talk about demolition tools in more detail below.) Curved-claw hammers remove fasteners and protect surfaces while they work. That’s why they make such common and effective choices for general purpose work. If you need to remove a nail during a simple repair job, a curved-claw hammer provides leverage with minimal effort. Curved-jaw hammers also help remove bent nails during construction, but they aren’t intended for demolition or prying work.
If you aren’t sure which of these Stiletto titanium tools to buy, consider whether you plan to use your hammer for prying. Straight-claw hammers better suit demolition jobs and those where you need to pry one piece of material away from another, and curved-claw hammers help remove nails during general construction jobs.
Lather’s hatchets have striking heads on one side, but they don’t have claws. Unlike most Stiletto hammers, these tools have hatchet edges that allow you to mark cut lines and pry edges on your jobs. In addition to their bladed edges, some lather’s hatchets have open-centered blades that reduce the weight of the tool for additional control.
Different styles of hammer come with different types of faces. A general purpose hammer looks different than a finishing hammer, and the surface of the face makes a huge impact on the finished product. The type of face you choose plays a part in which Stiletto titanium tools to buy, and it’s not hard to find one that suits your needs.
In general, a hammer with a milled face gives you extra traction on your hits. This surface produces indentations on some impacted materials, and they’re an excellent choice for rough carpentry and framing work. Smooth-face hammers are also ideal for framing, and they don’t leave dimpled indentations on the surface of your materials.
You can use Stiletto drywall hammers with milled-face heads to quickly hang drywall. Their bumpy surfaces give you a better grip on your nails, so you generate more force with every blow. This traction also increases your work speed. Because you need to tape, mud, sand and paint drywall, it doesn’t matter whether the face of the hammer leaves small imprints while you work. The best Stiletto hammers help you work quickly without damage to the surrounding surface.
While the style of claw and the type of face are the most important details to consider when deciding which Stiletto titanium tools to buy, you also need to think about the handle. Short-handled hammers may provide more control than those with longer handles, but they can’t provide the same amount of force. Long-handled hammers give your swings more power without much more effort and handle some of your toughest jobs. In general, choose short-handled hammers for precision work such as molding or trim and long-handled hammers for larger carpentry and framing tasks.
Magnetic nail starters come as standard features on many of these hammers. They provide one valuable benefit to Stiletto tools and are unique to this company. This feature prevents accidental finger strikes during the first few strikes of your job. In order to hold your nails during these positioning blows, the best Stiletto hammers have small slots on their faces that keep nails in place with magnetic force. This lets you position nails without putting your fingers in harm’s way. They also save time. When you use one of these magnetic starters, a single blow positions your nails and frees your hands for other tasks.
The main benefits of Stiletto tools apply to more than just hammers; they also apply to Stiletto wrecking and pry bars. These versatile tools give you a bunch of extra leverage for professional demolition work, and they won’t overload your toolbox with extra weight. Like the best Stiletto hammers, these tools rely on steel or titanium construction for strength.
Stiletto produces a variety of different pry bars, and each one serves a different purpose. When you’re considering which Stiletto titanium tools to buy for demolition, you will choose between multipurpose tools and those that specialize in a particular task. For example, nail-puller pry bars work in much the same way as the claw on a hammer. They slide under the head of a nail, snare the shaft and rely on leverage to pull the metal out of position. Nail-puller bars are one example of a specialized pry tool.
Multi-functional pry bars have several functions. These sturdy bars resist impacts, and their edges slide between materials when you need to add pressure for leverage. Like the best Stiletto hammers, some of these flat bars have specialized nail pullers as well. Stiletto provides multiple fulcrum points on these pry bars, so you can find a strong grip just about anywhere.
This Stiletto tools buying guide shows you some of the most important aspects to consider when shopping for hammers and prying tools, but the most important information comes from your own shop. You’re the best judge of your work, and you will determine which types of tools will most effectively address your needs. Determine what you want to accomplish, and you’ll find powerful, lightweight Stiletto tools to help with the job.