How to Loosen up a Stiff Knife

Last Updated: October 24, 2019

Are you breaking your fingernails and cursing each time you attempt to open your knife? Well, it's time to fix that stiff knife, keep your fingernails intact and ensure that those around you hear nothing but silence.

Steps

1
Carefully examine your knife. Tightness or stiffness in a knife comes from several sources and each needs to be handled a slightly different way. The typical causes are: Rust or aging, goop stuck on the knife, friction and tight hinges. Each of these is explored in the methods below, providing a solution for you to try.

Method 1

Method 1 of 4:

Rust/age

1
Check to see what color the blade or hinges are. Does the blade or hinge look slightly orange? Or even slightly powdery or white? This could be caused by the metal in the knife oxidizing to the point of the blades adhering to the casing or each other.
2
If the knife has only metal parts, simply give it a good soaking in a mineral oil. Then, buff it clean in a day or two. Once you've done this, keep the knife oiled from then on.^{[1]
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3
If the knife has non-metal parts, your job will be trickier. In this case, the metal parts need a good soak without getting the rust removal fluid on the non-metal parts. You can do this by masking the area off with tape, by using tiny brushes or "Q-tips", etc.
4
Repeat several times over the course of a week, buffing the rust and working the oil into the hinge(s). Use a heavy towel or wear gloves to protect your fingers from the blade(s) during this process.

Method 2

Method 2 of 4:

Goop

1
Observe whether the knife has some substance on the blades. Is it sticky? Did the knife fall into something that is just not wiping off easily?
2
Clean the "goop" off. How successful this will be depends on the type of "goop" it is. If you have no idea, it is best to start with the mildest cleaner available and progress to the strongest. Try cleaning agents in this order (rinsing and drying thoroughly in between): Water, ammonia, light mineral oil, "tape remover" or "goop remover" products from the store.^{[2]
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3
Thoroughly oil the knife when you're finished cleaning. This will prevent future oxidation.^{[3]
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Method 3

Method 3 of 4:

Friction

1
Clean the knife thoroughly using the methods outlined above. Sometimes a knife "sticks" because its blades were too snugly squeezed at the factory when the hinge(s) were pressed or riveted in. Loosen it as follows.
2
Oil the knife hinges thoroughly.^{[4]
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3
Protect your hands with either heavy gloves or a heavy towel.
4
Place a drop or two of mineral oil in the hinge area.^{[5]
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5
Open and shut the blade repeatedly to create enough wear in the hinge to loosen it.

Method 4

Method 4 of 4:

Loosening the hinges

1
Inspect the knife for a screw at the base of the blade. It may be under the clip. Depending on the knife, you may need to remove the clip to access the screw.
2
Use a small screwdriver to loosen the screw holding the blade in place. Be sure to not loosen the screw too much as the blade could potentially fall out.
3
Replace the clip if needed. Check that the blade moves smoothly.

Community Q&A

Question

I have a tactical force joker knife and it is painfully hard to open with my index finger . I don't have problems like this with other knives. How can I make it easier to open?

Princess XStaSy

Community Answer

What I did was wrap a piece of a plastic envelop around the blade. The plastic is easier to grip than metal. just leave it a little longer then the top of the blade.