Need help on this...

[ktabor72]

I posted a video http://www.youtube.com/watch?v=sd6PoinGufY in which i am throwing some rough homemade knives. I would like to make them a bit better. I made them from cold rolled steel i got from a local steel supply company. they are 1/4 x 2 x 10 inches. I am also starting some made of cold rolled steel from a farm store. 3/16 x 2 x 14.5 inches. I would like them to be able to stay sharp, not be too brittle for throwing but not bend a lot or "ding' each other when thrown in a group. I have little to no equipment for this so please keep it basic. Can I do this in an open fire? I like the idea of doing it as primitive as possible, (although i also like to use an electric hacksaw) All help will be appreciated. Thank you.

 

[hathegkla]

I can't view the video at work (I'll check it out later) but "cold rolled" doesn't really help when it comes to giving heat treat advice. if you can find out what kind of steel it is we can tell you how to heat treat it. its likely 1018 which isn't really heat treatable. I've actually been doing some experiments with 1018 with my bo shuriken, I've tried case hardening a few and plan on superquenching some as well to see if I can get any hardness out of them (I've heard mid 40's is possible using super quench or lye).

you will need equipment to heat treat them, hardening can't be done with a normal oven. you'll need a welding torch (or a forge or furnace), your home oven and a bucket of oil (or water depending on the steel). if you want more in depth info on heat treating check out the stickeys in the "Bladesmith Questions and Answers" section.

I make my shuriken (I've also made a couple throwing knives) out of mild steel with no heat treat, I actually prefer them that way because they tend to bounce back less, I just tap them straight as necessary. but knives are a different story. you can try work hardening the edge using a hammer but it might be a pain to work harden the entire knife this way.

 

[ktabor72]

Thanks for the info, i do like that i can reshape them easily and not worry if they get dinged up a little. I have a kiln my mother once used for ceramics, would that work?

 

[White Rabbit]

You will not be able to work harden mild steel very much, and certainly not with a hammer since it is the heat of the work that hardens the steel. You will unfortunately not be able to harden the steel you bought because the carbon content will be much too low. I would suggest getting some cheap carbon steel (5160 is cheaper than the shipping for it) and grind yourself some new throwers. You will be very impressed if you do a proper heat treat. I would, however, suggest tempering them down lower than normal after the heat treat (55HRC or thereabouts) as otherwise you will risk snapping tips with a bad throw.

Posting in shop talk will certainly get you more sophisticated and informed responses.

 

[hathegkla]

Thanks for the info, i do like that i can reshape them easily and not worry if they get dinged up a little. I have a kiln my mother once used for ceramics, would that work?

yes, I actually use a glass kiln. and I agree with White Rabbit, 5160 is a good steel for throwers, you can order it from McMaster Carr. To harden 5160 (after you've ground it to shape) heat the kiln to 1575 F, put the blade in the oven and let it soak for 5-10 minutes then quench in oil and anneal.

there are tons more detailed instructions in the makers section. if you're unfamiliar with the subject you should probably read up a bit first, especially on shop safety.

hope this helps.