*PLEASE* pretest it in a fire with PROPER PPE! I have had a rather nasty experience with exploding rocks way back in Boy Scouts 40+ years ago and now pretest all the ones I use around fires---The Irish Living History group I was president used to cook meat with hot stones and part of my duties was to test and prove in a new crop every year. (as I recall we had the best luck with igneous mafics...)
So what you mean is that you want to go see someone use it who knows how it's supposed to be used to see how it's supposed to work. I can buy the same materials for dinner as a cordon bleu chef but I guarantee it that mine will end up a lot different...
Remember when heating a blade the fat part heats slower than the thin part unless you take special precautions---look up tempering tongs for instance. I've tempered a lot of blades using my gas stove burners. (usually do a snap temper in the oven and then a differential temper using the burner) and at last I TOLD YOU SO! (also look up stress concentrators wrt blades)
can you get a picture of the vise with the missing end? One of the nicest mods I've seen on a postvise was a fellow who put a zerk on the end and so greased the screw from the back pushing any crud out the front of the screwbox. My travel vise is getting a bit gritty so I probably need to soak both pieces in oil for a week and then wipe them down thoroughly.