I have that exact shape on the end of my custom spear. Square, then 6 tines. Then the bottom is fused to one piece of hardened steel shaft(some special type of steel I'm told from Chicago). An old guy from the Rapids area built it. I was told mine was one of the last me made. Very nice.
Looking for an ice saw? I got mine here www.doublediamondspears.com. They are the BEST! His spears are a work of art as well. Gorgeous actualy. My saw was $150 (pictured below on top of the spears), nice PVC case, complete with handle, included.
His hand made spears (as of 3 yrs ago) were $250, and when I picked one up while getting my saw, I was speachless. Perfection is all I can say, and probably worth every penny. They have a wooden handle at the top. VERY pretty weapons! I have yet to hold a nicer, more perfectly balanced spear in my hand. He uses some sort of steel and gets it to look like platinum. Have a look for yourself on that site. Very nice guy too. He lives on site and hand makes these items in his large shop on site outside of Plato MN on a farm. If you buy one of these from him, he'll log your name w/ the product you buy. Free ice saw sharpening for life he says. I just cut my hole open this afternoon w. my saw - still razor sharp! - 12" of ice(2'x5' hole) like budda!