To start making you sheath you should have pvc pipe that has a circumference that is atleast a inch more than you blades width to account for the screws. If your pipe's circumference is more than two times the width of your blade you can just heat the pipe , flatten it and stick the knife in, but make pipe is to small for that so I started of by cutting the pipe to length en curring it length-wise so i can fold it open. I put the peices into an oven at about 200°C (which is about 392°F) I also stuck some butter knifes into the slits to help me open up the pipes. After about a minute they start to get soft thats when you take them out en place them between two pieces of wood an clap those peices of wood together. Ones the pvc has cold down you but them back into he oven, make sure to put something on the pvc sheets like the knifes cause the pipes are ganna want to return to there old shape
Ones the pvc is soft again take them out of the oven and sandwich your knife between the pvc sheets and than sandwich the knife and the pvc between the foam and the blocks of wood and clap them till the pvc has cooled down again. The sandwiching and claping is kind of hard to do fast so prepaire to have to do it over again a few times till you get it right.
When your pvc has formed correctly drill holes through both parts and insert the screws (i used meccano screws).
My sheath turned out a bit ugly but it works
After this step you are pretty much done, but you can cordwrap and heat treat the knife if you want.