Alright, so this dagger is decidedly *not* a DIY job, but it very well could be:
Technically, this is not a knife, but purely a dagger, as the design is one that is best suited for thrusting, and not much else. However if you had the right tools, this kind of weapon would be dirt cheap to make. You start if with a few basic ingredients, a section of steel pipe, a couple of nuts and bolts, a replacement rubber walking stick foot, a hacksaw, a drill, and a sharpening stone or grinder, mix them all together thoroughly, throw in a healthy quantity of elbow grease, and voila! you have a pipe dagger.
OK… that didn’t sound as simple as I thought it would. So don’t go trying this at home. But you get the idea. Actually when I first laid eyes on it I thought it was some sort of cheap, mass produced bayonet. Hey, don’t laugh… Wouldn’t be the first time some poor infantry unit got cheap equipment… :/