I have made snake hooks for using in the house (cage hooks) out of gun cleaning rods. I buy a 22 caliber or 20 gauge cleaning rod, bend a hook shape into one end (a vise is helpful for this) and then grind the taper into the end of the hook with a Dremel tool or grinding attachment on a drill. They aren't strong enough for field herping, but great for cages. One good thing about them was that they unscrew into sections. I used to have one in my glovebox or fanny pac when I climbed the mountains of West Texas for pulling Rock Rattlesnakes out of crevices (my lepidus hook).
I have also made sturdier hooks for field work out of thin steel roads that you can find at some hardware stores.
I have in the past made hooks out of certain garden tools. A hardware store near me years ago used to carry a single pronged cultivator (basically a hoe with a blade that was about 1/2 inch wide. Perfect tool and unbreakable.
However, I only made any of these hooks out of curiosity. For the last 22 years, I have had one fail-safe, perfect field hook - the Furhmont Stump Ripper. Unless you do something stupid with them (try to pry up buried boulders, play baseball with pine cones) they last forever. They aren't cheap, but you will go through a lot of "homemade" hooks that aren't as useful before you wear out a stump ripper. When you consider their potential longevity, they are one of the cheapest hooks on the market (mine has cost the equivalent of $3.50 per year based on current prices for the hooks - they were cheaper back in '81)! I know own two, my old standby 40" model from 1981 and a new 30" model.
Midwest Custom has one a similar one now that is cheaper, although I don't like it quite as much (it is slightly heavier).
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Chris Harrison