why? washers in a folder.

S

sixleggedinsect

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Dec 14, 2006
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why are washers important in a folder? it seems like they would allow a lot of play that wouldnt be there if the blade was pinned directly between the scales.

what would happen if i went without washers in a folder? (assuming nice flat smooth inside surfaces)

and further- why are there no washers available in 1/4 ID? is it possible to find super thin brass stock to punch and drill my own?
 
They are not necessary. Folders were made for a couple of hundred years without them.
Bill
 
In the book "How to make multi-blade folding knives" they describe making washers out of old razor blades. drill a hole and round them up on your grinder. I haven't done it but the pictures look good... I guess you could use new razor blades too.
 
sixleggedinsect said:
why are washers important in a folder?
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lubricity

it seems like they would allow a lot of play that wouldnt be there if the blade was pinned directly between the scales.
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are you speaking of a particular material, because I can't think of how PB washers would allow play. Washers, thrust bearings, shims, etc take up slack, not create it.

what would happen if i went without washers in a folder? (assuming nice flat smooth inside surfaces)
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just look at any frn handled folder

and further- why are there no washers available in 1/4 ID? is it possible to find super thin brass stock to punch and drill my own?
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yep
 
My Spyderco Ocelot does not have washers - and although it is nowhere near as smooth as my Sebenza with a pivot bushing and phosphor bronze washers - it still works.
 
In a lockback or slip joint folder, it is normal not to have washers.

In any type of linerlock or framelock folders, where a detent ball is used to hold the blade closed, some space must be provided between the inside of the frames/liners and the blade tang. This space is required to account for the protrusion of the detent ball above the surface of the liner/frame.

For example, I use .028 protrusion of my detent ball. So, I need .030 space between the frame and the tang of the blade. If the space is not provided, the detent ball will bind against the tang of the knife when it comes out of the dimple (detent) in the blade tang. This is because when the ball is riding on the tang, the outer surface of the spring is now in the same plane as the outer surface of the frame (or liner). The .002 additional clearance I provide keeps the outer surface of the locking bar away from the inner surface of the handle material that is attached to the frames. In a knife like the sebenza, where there is no scale covering that portion of the frame, the washer thickness could exactly equal the ball protrusion.

To further elaborate on some of the comments made here-Really high end lockbacks and slipjoints usually have raised, circular pads around the pivot pin. These pads are created by scraping the inside of the liners to a depth of .001-.002. around the area of the circular pad. This in effect, creates the same bearing surface as a washer, only thinner-So thin that if properly done, you can't really notice them. This scraping assures that there is no contact between the visible parts of the blade and the inside of the frames, eliminating radial scratches. Find a picture of a folder made by Tim Wright and you'll see what I mean. His knives can be disassembled, and you can clearly see the pad-up area in a photo of one of his knives in a disassembled state.

As to washers creating play, well, that's simply not true. Flat and parallel surfaces (blade/frame/washers) will mate up perfectly, and as long as the clamp-up provided by the pivot screw(or peened pivot pin) is correct, there will be no play whatsoever.

If you really want to get fancy, you can use roller thrust bearings like I do, which can be clamped up and provide almost no friction when the blade swings open, yet provide absolutely no sideplay.
 
Sigh....
No, Cliff. What I said was that you can make a knife without washers if you fit it properly. They were made this way for a long time.
Bill
 
rj martin said:
In any type of linerlock or framelock folders, where a detent ball is used to hold the blade closed, some space must be provided between the inside of the frames/liners and the blade tang. This space is required to account for the protrusion of the detent ball above the surface of the liner/frame.
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interesting. i hadn't thought of that. i am making a framelock, but i suspect i could still do without washers because it is just scales and a blade, no outside material to force the lock/detente against the tang. or am i imagining that?

As to washers creating play, well, that's simply not true. Flat and parallel surfaces (blade/frame/washers) will mate up perfectly, and as long as the clamp-up provided by the pivot screw(or peened pivot pin) is correct, there will be no play whatsoever.
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hm. i guess i was assuming there is a little deformation in everything (and all my knives have used plastic washers, not PB), and that tiny deformation would be magnified by the lever effect and seen as side to side play in the blade.

still, i would like to go without washers, if possible, to allow for additional support of the tang between the scales (more metal contact will result in less leverage on blade when prying, etc).

thanks for the replies, folks.
 
Aluminum scales need washers more than brass or stainless liners.
Bill
 
I can't say. I have never had occasion to work with titanium.
Bill
 
sixleggedinsect said:
how about ti scales and a 1095 blade? should i expect a lot of wear? im new with titanium.
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Titanium has a tendency to gall with steel or with other materials, which means that it sticks rather well. This is good for the lockbar, because it will grab the tang of your blade better than a hardened steel one would, but it also means that you're probably well served to get some good washers between the blade and the scales.
 
Washers are also a method to "fix" poor blade placement between liners. There's one major manufacturer whose knives have been found to have different washers and numbers of washers from knife to knife (e.g. one knife has a single washer on each side, another two, another one on one side, two on the other). The manufacturer won't say why, but my guess is to give a final adjustment to get a blade centered.
 
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