When I built my first hidden tang knife, I needed a tool to sew out the slot, where the tang would fit into the wood. As I had nothing that worked, I built one myself.
I called it a hidden tang handle saw (HTHS) as a joke on Instagram.
I used the same steel (3.2 mm of 1.2003 steel) for the saw as I used for the knife so I had the exact same thickness. And I had a pretty long triangular piece of that steel left that was perfect.
I drew the form I had in my mind directly on the steel and cut it out with the angle grinder then evened out the rough sides on the belt grinder.
I had seen an Youtube video of somebody doing a triangular cut. My first plan was to do a simple saw form with teeth. But I wanted to have a new challenge and i always strive to learn new things. So I chose to try out the triangluar form.
It took me a while but while filing every single tooth into form I already felt how sharp that thing would be. Yes I managed to cut myself in the finger. I hardened the saw and ground the shaft into a rounded form.
After doing my first handle I used the remaining epoxy to glue a simple little wood grip on the handle of the saw, just to have it nicely fitting into my hand.
I am very happy with the results.