Folding knives are incredibly useful tools; but like all tools, they work best when they are well maintained. Fortunately, keeping your knife in top working order is easy and can be done with a minimum of tools and equipment.
The first priority of folder maintenance is to keep it free of dust, dirt, pocket lint, and any other debris that could adversely affect the ability of the blade to open and lock properly. Carrying your knife with a pocket clip helps keeps it away from pocket trash and makes it less prone to attracting lint and dirt; however, you still need to check it and clean it regularly. For quick cleanings, the canned air available at computer supply stores can be used to blow dirt out of the handle slot and lock mechanism. For back lock knives, pay particular attention to the lock notch on the back of the blade tang. Lint has a tendency to accumulate here and can keep the lock from engaging properly. On Linerlock and Compression Lock knives, open the blade fully and blow out the area under the liner to remove any accumulated lint or dirt.
To clean your knife more thoroughly, get a bottle of rubbing alcohol and some cotton swabs. Flatten the ends of the cotton swabs with pliers or a tap from a hammer so they will fit into the handle slot more easily, then dip them in the alcohol and swab out the inside of the handle. If your knife is very dirty or the opening action of the blade is gritty, you may need to clean it by running it under hot tap water while scrubbing with a soft-bristled toothbrush and some dish detergent. To flush grit out of the pivot, turn the handle slot up so the running water flows through the pivot mechanism as you gently open and close the blade. Once you’ve flushed it thoroughly, use canned air to blow the water out of the handle and dry the knife completely.
In addition to cleaning your knife, you should also lubricate the blade pivot with a high-quality gun oil, silicone lubricant, or Teflon-based lubricant. Do not use WD-40, as it is not a true lubricant. Whatever lube you choose, use it sparingly. Oil attracts dust and dirt and excessive lubrication can actually cause your knife to become dirty. To avoid using too much lube and ensure you get it exactly where you want it, place a drop of lube on a wooden toothpick and use the toothpick as an applicator. With your knife’s blade closed and the pivot-pin end of the handle pointing up, place one drop on each side of the blade tang and allow it to flow into the pivot joint. Open and close the blade a few times to work the lube into the pivot and the contact surfaces on the side of the blade.
LinerLock knives sometimes fail to open smoothly because the ball bearing for the detent mechanism galls or scrapes against the side of the tang. If you open the blade partway and look into the handle near the blade, you can see the protruding ball bearing in the liner. A drop of oil right on the ball usually solves the problem and smoothes out the action. With some simple supplies and a few minutes of your time, you can keep your folding knife in top condition and ensure that it’s always ready when you need it.