The Resolute X-1 Story

Who.

Resolute Tools are designed by a group of aerospace engineers who design prototype-aircraft for a living. Every day we focus on designing aircraft structures with minimum weight and maximum reliability. Elegant design, clean load-paths, high strength-to-weight materials and cutting-edge fabrication methods are not luxuries—they are requirements.  

We live and die by the philosophy of purposeful simplicity.

We want to bring this obsession to you! These are the tools we dream of and spend our time building on the weekends. We want to use our aerospace expertise to bring you the sleek, lightweight and iconic tools of our dreams!

Why?

This whole thing started out with what we thought was a simple desire for a knife. We were looking for a well-designed, compact knife that used disposable utility blades. A knife that required minimal maintenance, had few moving parts and could easily be slipped into a coin pocket (you know, that useless fifth pocket in your jeans that you never use...)

We couldn’t find it.

Initially, we attempted to solve our problem by purchasing existing products but soon ended up with a pile of Everyday Carry (EDC) utility blade knives that didn’t suit our needs for a sleek, minimal tool.

We’ll do it ourselves!

Being the aerospace engineers that we are, we made the decision to just do it ourselves! Not being ones to shy away from a good problem, we’ve leveraged our design, analysis and manufacturing expertise to create the knife that we wanted.

 

Resolute X-1 features

 

Resolute X-1 dimensions

  • Frame material: Grade 5 Titanium
  • Slider material: 954 Aluminum-Bronze
  • Weight without blade: 0.312 [oz]
  • Weight with blade: 0.445 [oz]

 

How we got here: The Saga!

Requirements:

Just like we would begin any aerospace project, we started with a well-defined list of requirements that would drive the design iterations:

  • Simple cutting tool: Because well designed, single purpose tools are always better than their compromised multi-function counterparts. 
  • Utilize standard replaceable blades: Readily available, low-cost blades mean that you always have a sharp cutting tool with you. When flying commercial, just travel with the frame and go to any convenience store at your destination to pick up a blade. 
  • Quick, tool-less blade change (no fasteners): Field serviceable components should have minimal fasteners. Fasteners require additional tools, wear out and can get lost. 
  • Compact/Lightweight: This tool should be there when you need it but disappear when you don’t. 
  • Pocket clip: Simple and secure way of keeping the tool where you put it so it’s always there when you reach for it. 
  • Smooth: Free of aggressive texturing to minimize pant-pocket shredding. 
  • Single hand operation: The blade should be able to be extended and retracted with one hand and should have a consistent action with positive detents. 
  • Minimal: “Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.” – Antoine de Saint-Exupéry (writer and P-38 pilot) 
  • Proudly made in the United States of America: No explanation needed! 

Initial Sketches:

With a good list of requirements in hand, we set out to get some initial ideas on paper:

Resolute X-1 initial sketches

Material Selection and Initial Sizing:

For the frame, Grade 5 Titanium (6Al-4V) per AMS-4911 was selected for its excellent strength-to-weight ratio, corrosion resistance and our extensive familiarity with working Titanium into high-strength aircraft parts. AMS-4911 Titanium has a yield strength in excess of 130,000 pounds per square inch. The strength and a mid-range elastic modulus between that of Aluminum and Steel, makes this grade of Titanium strong and durable without being brittle—a solid choice for a frame with an integrally machined spring.

For the slider, we found that Titanium-on-Titanium created excessive friction and a “gritty” feel. To find a more suitable material, we consulted tribological engineering references and selected a specialty Aluminum-Bronze bearing alloy for its low coefficient of friction and wear rate when paired with Titanium. Testing exceeded our expectations, and we found this alloy slider provided a smooth, satisfying hand-feel.

Sizing "hand-calcs" were performed to design the thickness of the cantilevered beam spring and frame structure. We wanted to ensure that the spring would not yield under normal use (and abuse,) would have near-infinite fatigue life, and would provide adequate detent retention without being too stiff.

Detailed Analysis:

As an exercise, we took the analysis a step further and created a quick NASTRAN Finite Element Method (FEM) model to cross-check the stresses in the cantilevered beam:

Resolute X-1 analysis pretty colors

In-House Manufacturing:

All of the Computer Aided Design (CAD) modeling, rapid prototyping and Computer Numerical Control (CNC) machining has been done in-house! As with our day job of designing and manufacturing aircraft components, when we want something done fast and right, we do it ourselves:

Resolute X-1 waterjetting blanks

Resolute X-1 manufacturing

Product Testing:

No design is complete without thorough testing to verify that the requirements have been met:

Resolute X-1 in the pocket

Resolute X-1 in action

Resolute X-1 in the cockpit

The name: X-1

As we designed and prototyped our knife, we decided to name it after the extremely successful Bell X-1:

Bell X-1 courtesy of NASA

In the mid 1940's, a joint program was started between the National Advisory Committee for Aeronautics (NACA, now NASA,) the Army Air Forces and Bell Aircraft. This program ultimately produced the very first aircraft designed from the ground up as a research platform with one goal in mind. The aircraft was the X-1 and the goal was to push the envelope of manned flight beyond the sound barrier. In doing so, the X-1 paved the way for an era of American aerospace flight research and development. 

Following the X-1, experimental aircraft were developed that incrementally pursued higher performance. Higher, faster, further—methodically gathering data that would eventually be used in the Apollo program, the Space Shuttle and beyond. We believe the X-plane approach of continuous, methodical yet aggressive testing is worth emulating.

Resolute X-1 black and white

Our X-1 is the first product we've designed from the ground up with the consumer market in mind. It's a simple tool that's engineered to meet a very specific list of requirements. What we learn with the X-1 will pave the way for many exceptionally designed Resolute products to come!