Should work for any knife that is pointy at the end. May not work for squared off ends like a big meat cleaver because the sheath end is rounded off.
NOTE: New version coming soon that provides optional decorations on the sheath! FOLLOW me to be sure not to miss it.
There is an optional "window" cut out near the end of the knife. This window allows you to tell if the knife is serrated and has the shape you are looking for without unsheathing it. But be careful that when you insert the knife that your fingers are not gripping through the window. (Ouch!) If you think that's unsafe, there is an option to leave out the window and make the entire sheath solid.
The script rotates the sheath 45 degrees. This makes it print diagonally, allowing a longer sheath to be printed, since the diagonal is the longest dimension of your printer. On my 3D touch (10" x 10" platen) I can actually print a 14" sheath by rotating this way.
Just feed in the length, maximum width, and thickness of the blade (in mm) into customizer to generate a custom knife sheath.
The maximum width may be near the handle or may be near the tip depending on the style of blade, so measure carefully. I usually add another 1 to 2 mm extra to the width and length, and a quarter mm extra on the thickness. Maximum thickness is usually near the handle.
2 mm works well as the blade thickness for typical medium sized kitchen knives. I had a small paring knife that required 1.5mm to make a snug fit. Calipers are helpful here. On my printer I found it was perfect to make the thickness about a quarter mm bigger than the caliper readings of the thickest part of the blade (usually near the handle).
If you print one of these and find it is too loose to retain the knife, and you don't feel like wasting plastic by reprinting it with a smaller thickness, here is a trick: Use a butane torch or even just a lighter to heat up the sheath near the opening where the knife is inserted, then when soft press it down with a cloth for a little while until it hardens. You can use this method to make the sheath looser or tighter so you get just the perfect amount of retention without having to struggle to insert the knife.