Ryan M. Johnson talks about Tomahawks and Design (written in 2005)
Dad and I have made hand forged tomahawks now for over 24 years. Most of these hawks have been working historical reproductions and utility/camping axes. When it comes to design, my job as an engineer/historian/bladesmith is to draw from a wealth of historical axes aspects that we like and that can be executed with the tools and talents found in the shop. We may choose a blade shape here, a handle style there, a bowl shape from yet another piece. We may accurately copy just one tomahawk and it's details. There were thousands of tomahawks made in the 18th and 19th centuries, and because they were handmade no two were exactly alike. This makes my job pretty easy design wise: I pick the elements and execute these thoughts in the medium of iron, steel, wood and leather.
My friend John, who was in the Security Forces at the time, was the first guy to ask for a tactical tomahawk. He picked out one of our "Mohawk Spike" tomahawks as a basis for the design. This was a great choice — a design highly desired by tribes involved in the French and Indian War. These were people who relied on the tomahawk not as a backup weapon, but as a primary weapon and tool that they seriously used to kill with — and were good at it. I started off making a tactical version — forged alloy steel head, Micarta handle — the original design with modern day materials.
Then I encountered something that changed my outlook on this type of design forever. At the time I was reading Ayn Rand's The Fountainhead. Rand has character Howard Roark discussing architecture and design. He noted how people built wooden buildings. Then people made copies of those wooden buildings in stone. Then people made copies of the stone buildings in concrete and steel. They were using the same old designs with new materials. Why not, he suggested, develop new designs that took advantage of the new material properties and technologies?
To embark on designing a tomahawk that will be used in modern combat means embracing a new set of serious design issues that were previously not considered. The end user today is not necessarily interested in the historical aspects of the piece. The end user is not as interested in aesthetics. The most important part of the design is that the hawk can perform its tasks without any failure and with deadly efficiency. Worst case scenarios are played out with use, abuse, environment, and duration.
When Jimmy Lyle designed the knife used in the movie First Blood he commented that when designing the knife, he imagined himself stranded in the wilderness with just a knife. Then, he tried to think of all the things he would need in a knife to get out alive. Our design process takes a similar route, drawing on not only our experience, but more importantly the experience of those who have been involved in Special Op missions, and those who have found themselves on the battlefield in ugly situations.
There are three design laws when it comes to tactical weapons:
The RMJ handle is a full tang construction, 3/8 inch thick. To break the handle, you have to break the steel. This ensures that you always have a handle to hold on to. There is no need to have a handle guarantee because unless you use a cutting torch or a chop saw, you are not going to break the handle.
The handle is an overall oval shape. A round handle is difficult to index and is not comfortable in the hand when swinging or chopping. Control is very important when swinging something razor sharp; the oval shape helps facilitate this control.
Our Tactical Tomahawks and Axes are made from 4140 Chrome-Moly steel. This material is often chosen by designers for its toughness, and is used extensively in machinery, heavy equipment — even tanks. The tensile strength is much higher than that of commonly used knife-making steels. We use G-10 for our Eagle Talon and Kestrel tomahawks.
High durometer rubber is used for the handle of the Shrike. This provides supreme durability and electrical insulation of about 2500 volts. The G-10 handles are very tough, having over twice the impact resistance of Acetal, hickory and other commonly used materials. They also have a low moisture absorption rate and excellent UV resistance.
The spike is made long enough to inflict a deathblow, but short enough to keep the piece balanced. There is a lot of material directly behind the spike to ensure striking stability. The spike geometry is designed such that the best balance between penetration ability and strength is achieved.
The spike will penetrate a Kevlar helmet, easily punch through a steel clad door, and eats tires for breakfast. In other words, you can stick it in an assailant or use it to punch holes in 55-gallon oil drums to string roadblock cables (a common tactical tomahawk use).
We have found through personal experience and what has been related to us from the field that the spike is used about 70% of the time. Most don't realize all the uses the spike has until they have the opportunity to put it to use in the woods or in the city. The spike is what breaks the lock or chain. It gets you through the concrete block wall. It digs. It opens car locks. It is a pry bar. It is a reach extender. And the RMJ spike is designed so that it never gets hung up.
The blade geometry is designed for taking abuse. My concept was this: The spike and beard are your killing edges; the forward edge is for general field use, taking care of chores and chopping around. One guy in Afghanistan used his to chop armament off of a downed Soviet MIG.
The forward edge and the spike are flat ground. The flat grind is the strongest available, especially for impact purposes. The beard is hollow ground. This is a ripping, not impact, edge. The hollow ground edge cannot be beat for this purpose. But this left me in a bit of a dilemma: the meeting of the flat and hollow ground edges is relatively thin. This is great for ripping, as it hooks in quick and cuts fast, but not as strong as if both edges were flat ground. In this case, I sacrificed strength for cutting ability. Most of your hooking is going to be cutting and most of your impact hitting is going to be on the upper, forward edge and spike. Can you break the beard if you try hard enough? Yes, but I decided that the incredible advantage of the hooking/cutting edge outweighed the strength factors.
I have always admired the differential heat treatment found in Samurai swords. The cutting edge is hard; the spine is tougher and springy. This same concept is implemented with the Talon. The material starts out in the pre-hardened state of 30 Rockwell — a tough heat treatment that takes a lot of abuse. The edges are then flame hardened to 56 Rockwell. The cutting edges are hard; the remainder of the head and handle is tough. —RMJ