Folder pivot

T

terrinecold

Joined
Oct 3, 2016
Messages
113
Hello,
while my current project is a full tang knife but I can't work on it as I am away on a business trip for 3 weeks. During that time I am also thinking of the next one.
I want to make a lockback folder.

I have questions regarding the pivot. I have looked here https://www.alphaknifesupply.com/hardware.htm#HA-250Pivot and I am a bit confused and overwhelmed by the options available.

So here is a first question. To get a full pivot I think I need at the minimum:
1) a barrel let's say .125" Stainless Steel Barrel Pivot
2) 2 screws maybe: .125" Pivot Screw, Pan Head Torx, SS
I am wondering what are the pivot heads (vs scews) also if I need bearings and/or thrust washers.

So if anyone can explain to me what are the different parts needed in a pivot and why they are needed.
Keep in mind this is the first time I'll make a folder, I'd rather keep it simple (I still would like to understand what can be done but I'll probably choose the simplest solution).

Thanks
 
When the barrel goes all the way through the scales, use two pivot screws.

When the barrel is seated into shallow pockets on the inside of the liners, use two pivot screws.

When the barrel is hidden under bolsters, or will be flush on one side, use a flat head barrel and one pivot screw.

In most cases you need a spacer washer on each side of the blade. Phosphor bronze ones work well.

Thrust bearings are a much more advanced thing. Thrust washers are used with the bearings.
 
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And to add to Stacy's post, most traditional lack back folders are made like slip joints and use standard pin material and are hammered together. Mostly 3/32" or 1/8"pin material.
 
Ok so for a first folder what do you think will be easier. Using a pivot that I buy or using a pin. At this point I am leaning toward the second. What I have in mind is effectively that it should be like a slip joint but instead of a back spring there is a lock piece pivoting around a pin and a spring pushing up on the part of it closest to the handle.


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Ok so for a first folder what do you think will be easier. Using a pivot that I buy or using a pin. At this point I am leaning toward the second. What I have in mind is effectively that it should be like a slip joint but instead of a back spring there is a lock piece pivoting around a pin and a spring pushing up on the part of it closest to the handle.


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I bought a couple kits to put my first folders together. Just to get a feel for it before I try to bring a scratch design to fruition.
 
kuraki said:
I bought a couple kits to put my first folders together. Just to get a feel for it before I try to bring a scratch design to fruition.
Click to expand...

I hadn't thought of that. And I could fabricate and progressively replace the blade and the lock parts to more easily have a functional knife which I actually made.


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kuraki said:
I bought a couple kits to put my first folders together. Just to get a feel for it before I try to bring a scratch design to fruition.
Click to expand...

I hadn't thought of that. And I could fabricate and progressively replace the blade and the lock parts to more easily have a functional knife which I actually made.


Sent from my iPhone using Tapatalk
 
Just a FYI there is a critical locking angle that you should become very familiar with when building a lock back. Similar to a slipjoint the fit angle must be perfect or the blade will not lock up correctly and you can have excess up/down blade play. I use pivot barrels w/2 screws and 2 phosphor bronze washers (I polish the washers makes 'em silky smooth).

A kit would be a good learning tool....Like Stan recommended I took a few flea market cheapies apart to figure them out.
 
thanks all for your advices. I had seen the rough riders kit since the last post, but I thought that if I was to build a knife kit I might as well use one with better quality.
Unfortunately while I find that a lot of the knifekits kits are pleasing to my eyes they are mostly liner locks or buttonlock.
Except for this one
http://www.knifekits.com/vcom/product_info.php?cPath=1_359&products_id=1920
which I may end up buying.
There are also a bunch of nice french made ones but they are all slip joint.

So here comes my next question, in term of ease of making for a first (locking) folder, I think I was right to choose a lockback (vs a liner lock for instance) what do you think?
 
I think a linerlock is likely the easiest. Isn't the knife kit in your link a "slip joint?" What you're calling a lock back? I think those are slightly tougher to build not because they're terribly complicated but it seems that getting the interfacing lock geometry between the blade and the lock correct would be a little harder than a liner lock if only because it's hard to see when test assembling, but I very well may be wrong.

Oh I see. Slip joint is like a lockback under spring tension, no actual lock. My mistake.
 
When Iread about the liner locks first it seems torequire titanium liner, second you need a precise angle so it will wear down correctly. Then there is a detent ball.


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I may have missed the Ti part but I certainly use stainless 410 but I heat treat and spring temper the lock bar before bending. With the Ti there is no need to heat treat or spring temper the material has enough memory to be springy.
 
I can't heat treat stainless but I can do it with regular carbon steel. However I am not familiar with how to get it to a spring temper. Also shouldn't, I bend it in shape prior to making it springy？


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Spring temper just means softer than full hard really. Say 50 RC. You do this before bending. If you bend first you don't know that it won't relax in heat treat. At spring temper you can make the bend by over bending and it will return to that nominal location.
 
What John said is correct on spring temper also its going to be easier to clean up or polish while the liner is flat without the bend.
 
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