Hello Bladeforum. I am new to the forum and wanted to get a bit of advice. I am starting a throwing knife activity here in the UK. I have been using CS knives, but not a fan of the 1055 steel. I am going to have my own made using 1075 steel lazer profile cut, then hardened using a couple of local companies. My main question I have been asked by the company who is doing to hardening, what hardness would I like? Any advice.
Advice on throwing knife hardness
- Thread starter joolsh20
- Start date
joolsh20,
We we have been making and testing our own knives for about 3 years. We have done a great deal of research into steel type and proper temper. We have written some papers on our site (www.bellablades.com) regarding our approach and our findings. Our research has led us to believe that O1 tool steel and 5160 spring steel are excellent for making knives. They are all we use.
We have played with HRC 48 - 54. Over time, we have found that an HRC of 50 is a good number (5160 and O1) if you don't mind the occasional tip bend after multiple hard knife-on-knife hits. Around HRC 54 (again, O1 and 5160) we have had minor tip chipping after multiple hard knife-on-knife hits. After testing in these ranges, we determined that HRC 51-52 is an excellent compromise between hardness and toughness--no bends or chips unless seriously abused. Obviously, the type of steel used and where you are on the toughness/hardness curves is important to consider--we have a paper on that as well. I hope this helps.
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As an old knife thrower I'll mention the hazards of bounce-back. At one point I used 2"x12" lumber scraps as targets. I did a lot of early practice at a short half-turn range (around 9 feet given my grip at the time). A very hard target and a hard knife led to many close calls if I under-rotated the throw and the knife bounced back at me. The old cheap and soft malay throwing knives made of thin steel were not a problem. They would simply bend. When I got a better grade of that profile with a blade 2 or 3 times thicker and harder they would bounce. I switched to using cardboard targets made from three flattened boxes laced together with twine or glued together with spray adhesive. I would hang these from a sheet of plywood that was tilted towards me. Anything hitting that backstop were bounced down. The target was hanging off the leading edge of the backstop and was not only soft it would swing to absorb some energy. I never had to dance again. Generally I preferred a carbon steel blade about the hardness of a bayonet. 52 RC seems pretty good, but you can go a bit harder with a soft target.
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Just as a reference point, I have seen CS throwing knives being tested to have HRC of 56 at the tip