interesting knife design

[codemaker]

I've been designing a throwing knife that i want to be able to use as a general purpose knife as well. so far here's what i'm thinking of: 5160 spring steel, 1/4" thick, 4" blade, 8" total length, 30 degree inclusive angle(15 degree edge angle). do you think it'll be able to stick in well? it'll also have a recurve, with a hollow grind behind the recurve and a flat grind in front of it/at the tip. does this seem reasonable? i need a knife that isn't gonna chip or break from throwing, and that can still be sharp; hence my idea to use a combo grind with the recurve, to try to shelter the weaker hollow grind. my knives take a lot of punishment because there are a lot of rocks in my aria so whenever i mess up, there is a good possibility of it bouncing off my target and into a small stone.


by "general purpose", i mean cutting boxes, rope, milk jugs, shaving wood for kindling, and making tent stakes out of sticks. there's also the possibility of splitting small logs (~3" in diameter).

any input would be greatly appreciated. i'd also like some input on the difficulty of grinding an edge onto 5160 steel. it'll be my first time doing anything with this particular type of steel.

 

[Blackfeather]

8" is a bit short. Most throwing knives aren't suited to holding an edge, mostly because of the heat treating process required to accomplish a spring temper for making knives that won't snap. There are, however, methods to keep the edge a bit harder. Hollow grinds wouldn't be favoured, especially if you are changing grinds towards the tip, this could be an area prone to breaking on a throw. Grinding softened 5160 isn't too bad. Who is doing the heat treating?

Draw it out, see how it feels in a cardboard mock up, and consider the balance. Post a pic of your drawing, that helps us get a good idea.

Also, what throwing style?

 

[codemaker]

here's a pic of the drawing i sent to a machinist who's helping me make it. he will also be doing the heat treat. he doesn't have a lot of experience with knives, but he does have quite a bit of experience with other tasks requiring a similar amount of accuracy. as for throwing style, i throw several different ways. i am currently learning a no spin method, but my main method is just the standard spin method (from either blade or handle). i can also throw 1/2 spin reasonably well. thank you for the input! hopefully this picture will post correctly...

the grind change is right at the thickest part of the blade(where the re curve starts), so i'm not sure what effect that would have on the blades strength. also, the notch in the top is there for hand to hand combat purposes (i do a lot of martial-arts and just couldn't resist it). not sure if that would harm the knifes strength significantly. i've never tried to make a knife for both my martial-arts and knife throwing uses. and just about everything else...

 

[Blackfeather]

Unfortunately, it seems the image didn't work.

I understand why you'd design a knife to be able to do all of those things, I'm in the same boat a lot of times. Unfortunately, I can't say much more without seeing the design.

 

[AKmik]

A good place to look for ideas would be Gil Hibben designed throwers. His idea is the same, a knife that has an edge and can be thrown. Ideas anyway.

On the steel... I read everything I could on throwing knives and steels for a custom order a while back and there was quite a variety, Tru Bal uses C1050, theres a bunch of different SS . From what I read tough steel is all thats needed. I actually made the order out of good old 01 tool steel as well as five for myself and they have been outstanding. I also have a set of Hibben's, and a set of Boker Ziels that are 420J2 stainless. My O1 blades are heat treated as I normally do (harder than the hinges of hell) and they have held up FAR better than any of my others, no burrs, chips, nothing. They spark if you hit a knife in the target, and they will chip my concrete floor in the shop, but the tips are as clean as the day I ground them. Now these are throwers, so pointy not sharp at all. I wont even throw my blades in the same target as the 420j knives as it just tears them up that stuff is soft.
No matter what steel you go with , a good cutting edge will take a beating on mis throws as well as the tip if it is actually sharp and thin.

Look at the Boker Mini Ziel, that may be close design wise, and you could improve on the utility side of it depending on its main use.

Mine are 1/8" 01, and right at 10 1/4", on the lighter side but balanced very well.