My 5160 Competition Chopper

The North Coast Knifemaking Club undertook to host the first-ever Bladesports cutting competition event in KZN in September 2019.

CCC Comp Chopper by AntTopham

Bladesports, probably thanks to History Channel’s popular series “Forged in Fire” and “Knife or Death”, is taking off around the world and even here in South Africa, where there are aspirations to grow the event at provincial and national levels. Maybe even competing internationally???

Despite Bladesports being over 30 years old, there is not a lot of information available on what makes the perfect Competition Chopper. Given the competitive nature of the sport, this is not surprising as people are guarding their hard-won experience and competitive advantages but there are well-known US competitors like Big Chris, Big D Knives, and Jose Diaz to name a few, whose knives serve as great examples of high-performance designs.

My initial design shared a number of parallels to Dan Keffeler’s design as his overall design matched my initial sketches and idea on what a good competition chopper should be, quite closely to boot.

On June 20, 2010, Dan Keffeler broke the 2×4 speed cut record (1.21 sec).

Certainly, a good pedigree to start from.

International Bladesport Specifications:

  • Blade Length – 10″ (measured from the front of the handle to the blade tip)
  • Overall Length – 15″ (measured from the back of the handle to the blade tip)
  • Blade Width – 2″ (measured at the widest part of the blade)
  • Blade and Handle Thickness – No restrictions

Axes are synonymous with cutting wood, so I incorporated some learning from this old tool as it is designed to cut wood and the 2×4 speed cut is a big differential during a competition. Most feel that too pronounced a curve may push objects away rather than cutting them, leading to most competition blades having a flat cutting edge. I favored a slightly curved edge as a curve helps part the fibers of the wood easier than a purely flat edge.

An Apple Seed edge or the convex grind is recognized as the best blade geometry option for a competition chopper as it keeps a little “meat” behind the edge for stability. I have seen some flat grinds and even some hollow grinds out there in use that have held up very well in the competition, which just shows that there are many ways to “skin a cat”.

Convex-Appleseed-edge

Heat Treatment:

In typical form, I launched into the research phase of my preparation ahead of the event. As it was the first time using 5160 and the first time making a competition chopper. Needless to say, I wanted it to be perfect.

Stefan Diedericks (of SD Knives and Supplies) supplied the 5160 flat stock for all the club members. Luckily 5160 is popular steel for large blades, including swords, so there is a huge amount of information on the internet regarding the heat treatment and hardening of the blade.

Larrin Thomas of KnifeSteelNerds posted some really nice articles on 5160 specifically, pre-quench regimes and sub-zero treatments to enhance the already formidable properties of the steel. While the US competitors have moved on to more advanced steels like M4, Bohler Vanadis 4 Extra, K390, and newer powder steels. 5160 was a good starting point for us to get some learning under the belt.

Here’s the heat treatment recipe that I used. 

  • DET Anneal: AC1 750°C / 1380°F for 10min (air cool)
  • Austinizing: 830°C/1525°F degrees Celsius
  • Quenching: Fast to medium oil
  • Cold treatment: Freezer or acetone/dry ice or better yet, liquid nitrogen (your choice)
  • Temper: 180°C/350°F for 1 hour x 2

Overall I was really happy with the competition chopper’s performance in the event. It tackled even the toughest obstacles with ease and I came in 2nd behind Wesley Liversage in the inaugural 2019 KZN competition. I have since thinned the blade even more as I explore just how thin I can push the steel before it starts taking damage during the run.

Future Bladesport events will be advertised on the official South African Bladepsorts website: http://bladesport.co.za/