Step 1: Find a Scrap of Hardwood
Broken tool handles get saved to if they're Hickory or something because if worse comes to worse I can whittle a new end and reuse it in a pinch so I tend to have lots of scraps laying around the shop in buckets and boxes or piled on the floor depending on how tunnel visioned I became on the last project but I can see where it is likely people might not have a scrap of hardwood and if they want to try it with a piece of pine please do so and post the results here if you want. My only reason for using a hardwood was that if you're scraping something and hit a nail or something bringing you to an abrupt halt the softer wood might split by the razor being pushed deeper like a wedge.
Step 2: Basic Tools
You need a hammer and something to use as a light weight anvil like a scrap of 6 by 6, or a concrete floor and since I have one and I'm lazy I used a belt sander to shape the wood, but this could be done with a saw, you just need a long taper at the blade holding side to allow you to hold the finished tool between 15 and 30 degrees to whatever you happen to be scraping.
You need some razors like from a box cutter and a glass of water.
Step 3: Basic Method
I just used a marker through it in free hand, then ground the blade end with the belt sander and at the same time smoothed up the edges of the handle.
Once you have it in the correct shape you need to lightly but firmly hammer this end of the handle. You're trying to compress the wood fibers so it will take a firm hit but don't get the sledge out and shatter the wood.
Next you use the coping saw to cut about a 3/8 of an inch deep cut through the center of the blunt nose of your now pointed handle.
Next dip it in water for a minute or so and the compressed wood fibers will expand and get a firm grip on the blade.
When it becomes loose form the wood drying out just dip it again but typically it will hold a bade snug for months in my experience.
In the following video I only let it soak for a few seconds but was able to spear a block of wood with the tool and then scrape some paint from a piece of glass I had.
I must admit some failure, in the vid I wanted to do it in under two minutes and reality made that almost four but still, it would take me long to find my keys to drive to the store to buy a tool such as this if the need ever arose...
Step 4: The Vid
(Or super Glue!)
PS I tried fixing the sound a bit and cut it down to four minutes but it's still a bit rough...