Three-bladed Knife Geometry

[DayGlo_Koolaid]

I don't know if this has been done, or if the idea has been doomed from the start, but I want to do it simply for the 'cheese' factor. I want to take the concept of 1917 American trench knife blade, but expand on it a bit so it's more than just a shank. The best thing I can use to illustrate the concept is an architect's scale.

Ideally, each one of the 'lobes' could have an edge of 30 degrees, which I'm told is quite passable for a knife edge. With this shape on a blade, one might just be able, in a pinch, to sharpen it by dragging it against some concrete or similar readily-available abrasive material and have a decent edge for utility and fighting. This'd be impractical for many reasons- a sheath, for example, could be pretty tricky to throw together, but I still want to try for the sake of boredom. Does anyone know what this shape is called? Has this sort of blade been done before? Would I have to cast this shape to make a blade like this, or could I get some stock in this shape and slap a handle on it?

 

[DerekH]

I would say it is do-able. Might be kinda costly though, but others have managed to make something along those lines before.

 

[Stacy E. Apelt - Bladesmith]

I made and sold a three blades poniard . It had hollow ground flutes. The corner angles of triangle all must equal 180°. That make a simple equilateral triangle have 60° corners, which we would call the included angle, or 30° per side. This is twice the normal blade angle, and much steeper than an axe or splitting maul. Those max at around 45-50° included angle.
By cutting deep hollow grinds with a small wheel, you can make the edge angle much lower, and get it into a cutting range....but it will never be a slicer...just a stabber.

 

[Rick Marchand]

I don't think it could ever be a utility blade, like Stacy says. The pic that Derek posted reminded me of another sticker-type design... the "pipe knife"

 

[russianpolander]

That one is sweet Derek, what is it?