Selection of steel for best sharpness and hardness

[simweesiang]

I am doing a design project to make a shuriken with a thickness of 3mm, What the best steel for sharpness and hardness. What is the best way to make it hard? Cold forming, heat treatment...Etc. Would surface treatment, electroplating affects sharpness? Just a student, not a knife expert, any advice is appreciated.

 

[hank_rearden]

I'm not a smith but I understand annealed tool steels like O-1 are very soft and easy to work with. I suppose shuriken entails a lot of work with the bandsaw, grinder, and file. But I'm guessing they're also tricky to heat treat.

Take a plate of annealed steel. Draw in the pattern and cut out the shuriken with a hacksaw. Like I said I'm not a smith but I'm guessing a shuriken doesn't really need a hard martensitic surface at the points, just enough temper to keep the points from breaking. So when you've finished grinding and filing to the right shape, heat the steel till it's non-magnetic and quench in motor oil. At this point it's very brittle. Clean it and then re-heat until you have a bright blue color. That's it.

 

[DocJD]

For anything to throw , you need to focus on TOUGHNESS rather than hardness .

 

[elasmonut]

I would make em thinner maybe 2mm, and just use mild steel or 304 stainless if you dont fling em against hard targets they'll be fine, if they bend...bend em back.
If you really want to bother heat treating them then something like 4140 or 1055 would be fine, heat to non magnetic, quech in oil, then temper to dark straw would be a backyard smith approach.
Wouldnt bother plating or surface treatment anything you throw is gunna get dinged up and ruined, kinda like an arrow they will have a pretty limited lifespan no matter what you do!