Are washers necessary?

[Sharpnessis]

I have a spyderco caly 3, dragonfly nishijin and a canal street all with no washers. They are smooth as can be. So why do knives need washers?

 

[Rival1314]

so the liners & handles dont scratch the blade in the pivot area where it is thickest and produce unnecessary friction over time.

While they may not be "needed" its silly not to have them.

 

[9blades]

It's fine on lock-backs and axis locks, but without washers a liner locks detent won't function.

 

[dkb45]

It's fine on lock-backs and axis locks, but without washers a liner locks detent won't function.

Figured this out the hard way. Took a knife apart today and forgot a washer. Scratched the hell out of the pivot area, and the blade went nowhere. I don't see why all knives don't at least have thin washers. They are pretty much nothing but good.

 

[macknife12]

Really interesting question,
I have the Calypso which has no washers, and it's very smooth. It took a bit of getting used to the idea, but it makes you wonder if
It could be a step in the right direction.
I do in fact remember when tires had inner tubes, cars had carburetors, you know the good old days...kidding. But like I said, perhaps
the next thing in knife pivot technology is just around the corner.
Cheers

 

[cncpro11]

One of the smoothest knives I own is the Hogue X-04.
It has internal bolster plates but no washers.

 

[pbcg]

One of the smoothest knives I own is the Hogue X-04.
It has internal bolster plates but no washers.

You beat me to it, was about to post the exact same thing.

Plus the EX-04 is extremely smooth and has very solid lock up.

Edit to add: For those unfamiliar with the Hogue EX-04 it utilizes a button lock. Very strong solid lock with excellent tolerances maintained throughout the design.

 

[Kwon Kwang]

Depends on the overall design of the knife, but I like having them. They make everything smoother and prevent unnecessary friction.

 

[9blades]

Figured this out the hard way. Took a knife apart today and forgot a washer. Scratched the hell out of the pivot area, and the blade went nowhere. I don't see why all knives don't at least have thin washers. They are pretty much nothing but good.

Haha, the best lessons are learned the hard way.

Here's the reason for not having thin washers (I'm going to make this as clear as possible, it's kind of hard to explain). You have your lock-bar and the detent, the detent is raised above the surface of the lockbar so when it moves over the detent hole it falls in and keeps the blade closed. If you measure the height from the top of the detent ball to the surface of the lockbar that will give you the minimum thickness of the washer. Anything thinner than that and it will be the same as having no washers at all. Also, if you push the detent ball further into the lock-bar the detent will be weakened significantly. the I hope I did a good enough job of explaing that.

 

[Jaytaylor]

Techically they are bearings, not washers.

As bearings they do two things -

1. Provide a bearing surface for the blade tang.
2. Sacrifical wearing component - the bearing sustains the most wear rather than the more expensive parts.

Those knives without bearings, what is providing the bearing surface? plastic handles? do they have blade play?

 

[cncpro11]

Techically they are bearings, not washers.

Those knives without bearings, what is providing the bearing surface? plastic handles? do they have blade play?

One way to get around the problem of bearings is for mating parts to have a surface finish of 32 micro or better.
The lower the micro, the less wear you will have.
This is the case with the internal bolsters on the EX-04, which as I've previously stated is one of the smoothest knives I own and lock up is very solid.
Keeping the functional surfaces clean and lubricated also relieves wear, as well as not being a habitual flicker.

Eta: come to think of it, none of the traditional type knives that I own has any washers or bearing either, and I haven't noticed any of those with blade play.

 

[gomipile]

Many handle materials, such as G10 and Zytel, are inherently abrasive. It would be foolish not to put something between such scales and the blade tang.