Abstract:

This video documents the creator's ambitious project to improve his 3D-printed shotgun axe, a tool designed to split logs using the high-pressure gas from a shotgun shell. The project tackles three main challenges: a lack of ammunition, inconsistent blade penetration, and an unreliable trigger mechanism.

Initially, the creator attempts to replace shotgun shells by building a dry cell oxyhydrogen generator, but post-construction calculations reveal the resulting gas is far too weak. He then designs and 3D prints two new stainless steel axe heads (curved and arrowhead) for better penetration. The most significant upgrade is a new, spring-loaded, lever-action trigger and reloading mechanism machined from brass to ensure consistent firing.

Field testing proves dangerous when a new, narrower axe head over-pressurizes and launches itself like a rocket. Success is finally achieved by combining the new reliable trigger with the original, wider axe head. A final analysis concludes that performance is heavily dependent on wood type (soft pine vs. hard eucalyptus), the timing of detonation, and penetration depth. The video ends with the creator vowing to build a "Version 3" to conquer the more challenging hardwood.

Building a Better Shotgun Axe: From Failed Chemistry to Mechanical Success

• 0:00:10 Improving the Shotgun Axe: The creator sets out to improve his metal 3D-printed axe, which splits logs using shotgun shell pressure. He identifies the need for a better blade shape to ensure a proper seal for the gas pressure.
• 0:01:43 The Ammunition Problem: Faced with a shortage of shotgun shells, the creator devises a plan to replace gunpowder with oxyhydrogen gas, a highly combustible mixture of hydrogen and oxygen produced from water.
• 0:03:39 Building an Oxyhydrogen Generator: He constructs a stainless steel "dry cell" generator to perform electrolysis on water, separating it into hydrogen and oxygen gas.
• 0:05:47 A Critical Miscalculation: After building the generator, calculations show that the 40ml of oxyhydrogen gas it can inject produces only 300ml of expanded gas, about five times less than the 1.4L of gas from a single shotgun shell, making it completely underpowered for the task. Key Takeaway: Do the math before you build.
• 0:07:58 New Axe Head Designs: Abandoning the gas generator, the creator receives two new 3D-printed stainless steel axe heads: one with a curved blade and another with an arrowhead shape, both designed for better penetration.
• 0:09:48 Engineering a Reliable Trigger: To fix the unreliable firing of the original, he designs and machines a sophisticated brass trigger mechanism featuring a spring-loaded hammer, a lever for reloading and shell extraction, and a locking system for safety.
• 0:13:03 Dangerous Field Testing: Testing the new components leads to a dangerous failure. The narrower internal volume of the new axe head causes a massive pressure buildup, launching the axe head off its handle like a rocket.
• 0:15:02 The Winning Combination: The creator finds success by mounting the new, reliable trigger mechanism onto the original, wider axe head. This setup proves effective, consistently and spectacularly splitting logs.
• 0:17:13 Analyzing the Variables for Success: In a post-test analysis, the creator identifies three key factors for a successful split:
  • Wood Type: Soft, straight-grained pinewood splits easily, while dense, knotted eucalyptus is extremely difficult to penetrate.
  • Timing: The explosion must detonate at the precise moment the blade enters the wood to use the swing's momentum.
  • Penetration: The blade must penetrate just enough to create a seal for the gas without creating a premature crack for it to escape.
• 0:19:25 The Next Challenge: Frustrated by his inability to split the hard eucalyptus logs, the creator vows to design and build a "Version 3" specifically to conquer the toughest wood.