This tool is very easy to make and use. It requires only a small amount of basic tools to make it. I bought a 5 foot piece of .5 PEX and a PVC el big enough for the PEX to fit inside. I cut a small slot in the side of the ell for the blade with a hack saw.
My first attempt was a slot cut at about 40 degrees. I used a small blade for a box knife, but it broke where the blade is scored to snap off when the end section gets dull. Also it cut the PEX 1 inch wide, which was wider than I wanted.
On my second attempt, I cut another slot at 20 degrees and used a small piece of .040 stainless (.25" x 1.25" ) and sharpened one side. This tool cuts a 1/2 inch ribbon.
I glued 3 small pieces of PVC inside to hold the PEX against the blade.
The PEX tubing I used is labeled ".5 PEX" but measures .485 ID and .625 OD. I bought a 5 foot piece because I didn't know if it would work or not. They sell longer pieces.
The 1/2 PVC tee is schedule 40, not the thinner 200 psi. It measures .840 ID. Lowes bar code number is 25528 14522.
You will need a hacksaw, a hose clamp to hold the blade in place, a nut driver or screwdriver to tighten hose clamp. My total cost was less than $5.00.
I used a tee so I could hold it in the vice, but it is so easy to turn, you can hold the tee in one hand and turn the PEX pipe with the other. I was amazed as to how easy it was to cut the PEX. I was going to turn it with a Vice Grip pliers, but it was not necessary. Have fun.