When it comes to your knife sheath cracking, it can be the material, its thickness or the manufacturing process. My very first extruded sheaths had a cracking problem. It was fixed by making them thicker, but what if the sheath is thick and it still cracks. Then there’s probably an issue with the material. Switching to another material isn’t that simple. Extrusion tooling is designed to run the type of plastic you’ve chosen. Another material will have different properties that won’t be compatible your current tooling. The tooling for the Knife-Guard brand was changed several times before I was satisfied with the product.

I was very surprised to read about a fabricated sheath that cracked during shipping. It can’t be the material. It was made from a textured plastic sheet that’s often used in thermo-forming. So, this must be a problem with the manufacturing process. As a plastic fabricator I know if you don’t heat the material enough before bending you can put a crack in it. I took one of my 40 some year-old fabricated sheaths and tried to break it. It just bent.

I once got a call from a former customer who switched to sourcing their sheaths overseas. They said that the imported sheaths are cracking. I said, were they left in the sun? They said, no. You see even my sheaths will get small cracks called crazing if left in the sun too long. They aren’t UV stabilized. The sheaths had adequate thickness, so it has to be the material. I’ve read reviews of another brand that look the same, with the same problem. Do you suppose they came out of the same factory?