I used abs black pipe from home depot.
1 1/2" schedule 40 ,heat at 350F in oven(electric) ~5min. be sure to place some small wet wood sticks on the oven rack so it doesn't stick to the rack
keep careful eye on pipe once it gets nice and pliable,remove it quickly from oven(use gloves) and insert machete to be used then step on it on the floor and move machete in and out of the sheath (you will have about 20 sec. to do this ),that way when it hardens you can still remove the machete.
I used a piece of 2x10 plank on the floor and a piece of plywood to step on, to sandwich the abs,that way the handle is not touching the floor and you get a nicely centered placement in the sheath.
One more thing to remember is make the sheath ~1"(you will get a real nice pinch on the bottom) longer than the machete so you can drill a hole through it to strap to your leg and also I use it as an anchor point to suspend the sheath for use around the waist.
let me know I can send you a pic. this works really nice and you can do a lot of different mods i.e. add innertube around the sheath to hold ferro rod, knife,etc...
would post a pic but not to tech savvy,sorry guys