I'm sure most of you that make knives run into people who want something dear to them repaired.  Today a gentleman brought me a very unusual piece.  It is a throwing knife made by UII, an obscure (as far as I can find) company/inventor in the late '60's.  The blade is 440B stainless, mounted on a heavy steel ball with an aluminum handle.  You'll notice the rubber stop on the back, that comes off with plastic fletchings on a spring come out as stablizer.  The knife was designed to be thrown like a baseball for "hunting".  He still has the brochure and the uses are somewhat comical.  Well there is still a warning paper that say's not to throw it into trees (what else does one do with a throwing knife?) that is just what his grandson did.  The brake is odd to me, idk if it will show up but it looks like a hard skin with a rather rough grain structure.

Needless to say a replacement blade has to be made.  My problem, how is the blade mounted?  I'm assuming that it is threaded with some mechanism that locks it in.  The slot is smaller than the blade is tall so the blade has to slide in from the top.  Any ideas?  Ever seen one before?  Should I tell him to use it for a trotline weight? :unsure:  

Very unusual knife. I would think your going to have to get the handle off the ball, then you should be able to see how it's attached. Honestly though unless the handle is threaded and just screws into the ball I doubt it will be able to be removed or repaired. Can the fletchings be removed? If so maybe you can see inside and tell what's going on.

Trying to google Ull knives I got ulu knife, Harvey Hull Knife, and my favorite Dull knife. No Ull though.

Look for it with uii instead of ull. Among other tidbits, it pops up that it's supposed to float, and i think the cap on the back of the handle comes off.  Possibly threaded with a nut if that handle is hollow?

Look for it with uii instead of ull. Among other tidbits, it pops up that it's supposed to float, and i think the cap on the back of the handle comes off.  Possibly threaded with a nut if that handle is hollow?

I goggled it, not the same critter.  This thing couldn't float with a set of water wings.  It is quite hefty (at least a pound).  The handle is hollow and houses a set of plastic fletchings that pull out.  There is a spring somewhere in between. 

***side note question** what would cause it to break in that manner.  It almost looks like there is a hard skin and the inside wasn't.  I don't work with stainless but have broke a few and never seen that before.

It looks like the words Pat Pend created a stress riser that caused the blade to brake, if you notice it broke right at the bottom of the stamped wording.  The serrations for the thumb would also add to this.  It is difficult to see any of the broken area from the photo's you posted, could you post one that shows both ends of the break end on.

I guess a stress riser along with that extremly ridged and heavy guard.  I still haven't figured out how that thing is put together.  Getting a good close shot is rather difficult.  <_< 

Looks like the grain structure could've been made finer than that, to me at least. And the blade looks to have been epoxied in, in which case you may be able to heat it and break the bond, then slide the stump out.

I don't think it's epoxied, it was made over 40 years ago.   I'm just gonna have to tell the fella that the odds are it will be scarred up if I deconstruct it.  This knife/spear was a good idea but poorly executed. <_<  It might be fun to one day construct one properly.  I'm thinking 5160 barstock forged in one piece with a distel taper and a proper temper this time. ;)

I was going by the fine yellow crusty looking stuff around the tang but you make a valid pt about its age. And if you do reconstruct this thing correctly, PICTURES! I think it'd be impressive