Rookie Year: The Engineering Intern’s Toolbox (Part 3)
A Series of Technical Blogs for Engineering Interns & Entry-Level Engineers

It’s hammer time… cue the music. To most interns and entry-level engineers a hammer is a hammer. “They all look the same and they’re all used to bang stuff together, right?” Actually, it is not that simple. Sometimes using the wrong hammer can be dangerous to the user or cause damage. Other times using the wrong hammer will lead to wasting a lot of time with little results. All hammers were designed and engineered for a specific purpose. Knowing that purpose will help you select the right tool for the job…and make you look like less of a rookie. Let’s learn how to choose wisely.

1. Claw Hammer (Light Duty)

Claw Hammer and Framing Hammer

When most people think of a hammer they picture a claw hammer. This is because they are the most ubiquitous hammer around a house. Claw hammers are used in construction or maintenance to drive or remove nails. They consist of a large cylindrical striking head with a flat face and two claws on the opposite side of the hammer head. These claws are designed to be used like a crowbar to pry up nails. A standard claw hammer, pictured on the left in Figure 1, has a solid metal head with a wooden or composite shaft which is meant for light duty. A framing claw hammer, as pictured to the right in Figure 1, is a single piece of metal. This type of claw hammer is meant for prying or heavy-duty use where a wooden handle would break.

Claw hammers are typically lightweight and measured in ounces not pounds. They are built to be swung at thousands of nails by a user all day long. The lightweight design allows the user to swing very quickly to deliver a great deal of force. Because they’re lightweight they are suited for striking lightweight metal objects like nails. They work poorly for hitting solid heavy objects. In fact, striking heavy objects with a claw hammer can be dangerous as the hammer might rebound and strike the user or others. Additionally, because the hammer head is hardened for wear resistance, it will damage softer objects such as woods, plastics, painted surfaces, and metals like aluminum.

2. Ball-Peen Hammer (Medium Duty)

Ball Peen Hammer

Like the claw hammer a ball-peen hammer shares the same striking surface but in place of the claw it has a domed head referred to as the “ball”. This ball is used to deform or “peen” soft materials. Ball-peens can be used to drive nails, hardened dowel pins, or other small lightweight metallic items too large for a claw hammer. Like the claw hammer they are ill-suited for hammering heavy or soft objects as they are relatively lightweight. A good rule of thumb is to use a ball-peen when the object being struck is bigger than a nail but smaller than the hammer head. A ball-peen is available with either a wooden or all-metal handle. An all-metal handle is useful for heavy, repeated striking.

Riveting with Ball Peen

The historic use of a ball-peen was to manually round off edges of rivets. A rivet is a fastener that joins two pieces of material together. Before welding, it was the primary way to connect large steel beams and plates together. A hole would be drilled between the two plates to be joined. Then a soft pin (rivet) would be inserted into the hole. A heavy anvil would be placed on one side of the pin and the ball-peen would be used to strike the opposite side. With enough force, both ends of the pin would deform and flare out. The hammer would be spun around and the ball end would be used to mushroom (peen) the top of the flared pin. As the rivet was peened over it locked the two plates together. Hence the name… using the ball end to peen the rivet.

3. Lineman’s Hammer (Heavy Duty)

Linemen's Hammer

A lineman’s hammer is a heavy hammer, measured in pounds, used to knock around heavy and solid objects. Unlike the claw or ball-peen, it is meant to be swung much slower letting the weight of the hammerhead do the work. This is a “get out of the way” hammer as it’s essentially a small sledge hammer. The main striking face is large and dense while the rear side tends to be pointed. The purpose of the pointed end is to concentrate all the force from the hammer to a smaller area and amplify the impact.

This hammer is meant to drive heavy objects together or apart, such as spikes into utility poles, which is where it got its name. A variant of this hammer is used by blacksmiths to hammer red-hot metal in order to form it or by machinists to join large parts together. Due to the hammer’s weight, it is not easy to control mid-swing. Therefore, this hammer is not meant for highly precise repetitive tasks. Likewise, due to the weight of the hammer, it will damage just about anything that isn’t as hard as the hammerhead. Do not use this hammer on surfaces or items you don’t want to break, mar, or dent.

4. Mallet (Light duty – Non Marring)

Rubber Mallet and Wooden Mallet

A mallet is a hammer used to strike an object without damaging it. They are typically lightweight and made from solid wood, rubber, or leather. Due to their lack of weight, they are typically not very good at moving objects a great distance. Instead, they are better suited for seating (nudging) objects together. Likewise, mallets have large blunt faces which make them poor for precise work. Because they land with a relatively soft blow they are also good for driving chisels and cutting tools. Their mild blow ensures that you will not damage the chisel or take too large of a cut. Be warned that mallets tend to rebound due to their soft heads. If striking a hard object it is possible it could jump back at you.

5. Soft Face Hammer (Medium Duty – Non Marring)

Soft Face Hammer

A soft face hammer has the weight of a ball-peen but contains soft polymer, brass, or rubber striking faces. Most soft face hammers contain two cylindrical striking faces each having dissimilar material types. For example, one face would be a soft rubber while its opposing face is made from a harder urethane. This gives the user options and combines two tools into one neat package.

These hammers are good for hammering objects with a greater force than a mallet without damaging the object the way a solid metal hammer would. Additionally, the head of the hammer tends to be much smaller making them more ideal for precision work where a mallet wouldn’t fit.

6. Dead Blow (Heavy Duty – Non Marring)

Dead Blow Hammer and Internals

A dead blow hammer is a solid polymer mallet with a hidden secret. Inside the hammer head is a cylinder filled with lead shot, sand, or steel shot. When the hammer is swung the shot lands dispelling all of the energy into the object being struck. This virtually eliminates any rebound within the hammer’s head, which is a common problem with a standard mallet. The shot delivers a great deal of force per swing without the hammer needing to be very heavy.

Due to the dead blow being made of polymer it is very helpful in minimizing the damage to a struck surface. Therefore, the dead blow is used very similarly to a traditional mallet but for objects which need a little more force in order to move. Dead blows are great at dislodging stuck parts, driving stiff wooden joints together, or to pop small dents out of sheet metal. This hammer is also ideal for striking objects with a great amount of controlled force such as chisels and other sharp objects. This allows for more aggressive cuts without damaging the chisel.

7. Sledge Hammer… (Enough Said)

Sledge Hammer

The sledge hammer is the big daddy of them all. Chances are if you are using a sledge hammer in a work environment you are at a construction site, large heavy manufacturing site….or YOU ARE DOING SOMETHING WRONG!

A sledge hammer is a VERY heavy hammer with a handle as long as an axe. If you need more description than that you are on your own. It is meant for blunt force trauma combining its heavy weight with the long handle to swing it quickly. This combined effect delivers a great amount of force to a small area in order to move or more likely to break something.

Written By: Sean Derrick – Product Development Engineer |
Sean has a B.S. in Engineering Design and a M.S. in Manufacturing Engineering from Western Michigan University. He has over 7 years of product development experience in a variety of industries ranging from medical, automotive, furniture, consumer products, and defense. Sean enjoys hiking, mountaineering, skiing, movies, and is pursuing a Ph.D in his free time.