What Is a Bushing in a Knife?
If you have handled a Sonora, you have felt it. That smooth, controlled, almost glass-like action. It doesn’t happen by accident. It starts with something small.
What a bushing actually is
A bushing is a small, donut-shaped piece of hardened steel that sits at the center of the pivot. It offsets the washers from the blade, allowing the blade to swing freely on a thin cushion of oil.
Think of it as a spacer between the blade and the washers, keeping everything aligned and moving smoothly.
What it actually does
In most washer-based knives, tightening the pivot too much will lock everything up. So you end up chasing the perfect tension. Tight enough to remove play, loose enough to still move.
A bushing removes that problem. It takes the pressure instead of the blade, which means the pivot can be fully tightened while the blade still swings freely. No guessing. No chasing the pivot. Just consistency.
At a mechanical level, the bushing sets the spacing between the blade and the washers. It prevents the pivot from compressing the system beyond that point, which is what allows the knife to stay smooth even when fully tightened.
Where it lives
The bushing sits in the pivot, between the blade and the washers. It controls the spacing and how everything interacts under pressure.
How it should feel
A properly tuned bushing system should feel like the blade is gliding on glass. Smooth and controlled, with no binding.
When dry, there may be the slightest hint of play. That is intentional. That is how you know it is tuned correctly.
Why we use it
MachineWise started as a balisong company. In that world, bushings are the standard because they work under real use.
When we designed the Sonora, we didn’t switch systems just because it is more common in folding knives. We kept what works. Bushings give us the consistency, durability, and control we expect from our own designs.
Bushings vs washers vs bearings
Washers are smooth and simple, but they require careful tuning and adjustment.
Bearings are fast, but you can feel them. You feel the balls moving in the system, and they tend to be less durable over time.
Bushings sit in the middle. You get the smoothness of washers with the consistency of a system that does not need constant adjustment. Each system has its place, but they behave differently under use, wear, and tuning.
Bushings are more forgiving because the system is defined by the bushing itself, not just pivot tension. But they only work if they are done right. When they are off, you feel it immediately. Too small, and it behaves like a standard washer setup. Too large, and you introduce blade play that no amount of tightening can remove.
Getting it right means fitting the bushing to the blade within extremely tight tolerances (within a few ten-thousandths of an inch). That level of precision is what allows the system to work the way it is supposed to.
Do all knives use bushings?
No. Most folding knives use washers or bearings.
Bushings are less common because they require more precise machining and tuning. When done correctly, they create a more consistent and controlled action, but they are more demanding to get right.
Why this matters
The pivot isn’t just a detail. It is what you feel every time you open the knife.
The bushing system is a big part of what gives the Sonora its character. That smooth, controlled, glass-like action people notice right away.
