How Do You Replace a Knife Sheath?.

Buck expects the sheath to go first

Buck's FAQ answers "How can I get a replacement sheath?" with a plain expectation: "Chances are, the sheath will wear out long before the knife does." A new sheath asks for the same care as the old one when the knife goes back in, and Buck's safety page says not to push past resistance when returning a knife to its sheath.

How each maker states fit

Each maker states fit in its own terms:

• Buck: by model. Buck's sheaths page offers "replacement knife sheaths for almost every model," for fixed and folding knives.
• Case: by pattern and size. One Case leather sheath "can fit almost all of the medium Case patterns," another "almost all of the medium-to-large Case patterns," and Case's Trapper sheath "was designed with the Trapper in mind."
• Böker USA: by pattern and closed length. Its leather trapper sheath is fitted to the Trapper pattern and, Böker says, also suits similar pocket knives up to 4 1/4 inches closed.
• Hogue: by knife and blade length, naming each fixed-blade sheath for a model and blade, such as its EX-F01 with a 5.5 inch or a 7.0 inch blade.
• Gerber: its FAQ answer on parts and sheath requests says "All parts are proprietary to the product."

Checking the fit for one knife

For one knife, fit can be stated in two places: the maker's own page or fit line for that model, and the product data of a sheath sold on its own, which often names the knife or the size it fits. Read both, and where they differ, take the question to the knife's maker.

What each sheath material is, by its makers' own account, is gathered in how sheaths of leather, nylon and Kydex differ, while the Kydex entry explains whose name Kydex is.