Question about friction folder pivots

C

carbonman

Joined
Jan 26, 2004
Messages
292
I've searched, but can't seem to find an answer on here or general Google search.

I'm trying to build a friction folder with a one sided handle. Chisel ground knife will lay flat on surface of handle. My question is about the pivot...

When using a pivot consisting of a barrel and two screws, what prevents the screws from loosening as you open and close the knife? While waiting for some pivot samples, I'm using a temporary Chicago screw (barrel nut and 1 screw), and it loosens quite easily as I open and close the knife. I'm not using washers as I want the blade to sit as low as possible on the handle. This probably involves some pivot theory, but again, can't seem to find anyone explaining how a pivot should work properly anywhere. Thanks in advance for any suggestions or info.
CM
 
Loctite will prevent it. Otherwise it will come loose. At least that’s what I’ve encountered in my limited experience.
 
A sketch or photo of your folder would help us help you.

Loctite is almost a necessity for adjustable tension pivots. The blue type is easy enough to re-adjust. You really need Torx screws when doing pivots.

As far as a one ended pivot (one sided handle), it sounds like bad engineering unless the single screw is well over twice the size as normal. I would think it would require a #8 or even #10 screw to withstand the side load. Obviously, the single handle side would have to be more robust to take the same pressure.

The arrangement that sounds workable to me would be using a "Tee" nut from the handle side (shaft would be the pivot) and a wide face screw as the pivot screw. The shaft length would be filed to allow just enough clearance for a friction washer (nylon) on each side of the blade. The screw would apply the necessary tension … and Loctite would keep it there.
 
You mean something like this, right? Lots of manufacturers use this for light duty knives... save weight and space. Josh gave you some good info.

376400.jpg

61lnSjYu7iL._SL1020_.jpg
 
You could use a 'D' lock pivot on your handle side. And maybe a small washer on the top (no handle) side. I've made folders like that with no loctite required.
 
Hi Stacy,

The handle will act more like a one sided sheath rather than a knife handle that will take side to side torque. Ill try posting a sketch or photo ASAP. My only goal is to have very tight tension on the blade so it will not swing open when in someone's front pocket. The knife itself is actually a small fixed blade.

Thanks!
CM
 
Last edited:
Rick Marchand said:
You mean something like this, right? Lots of manufacturers use this for light duty knives... save weight and space. Josh gave you some good info.

376400.jpg

61lnSjYu7iL._SL1020_.jpg
Click to expand...

Rick,
Yes, that is the concept, however I'm not going to have a detent ball to keep the knife closed. Only relying on friction and that's where my issue comes in. When I tighten the pivot screw down to desired tension, it loosens up after opening/closing a few times.
Thanks!
CM
 
I see a few makers using this type of pivot. Any idea what it's called or who makes them? Checked all of the online knife parts sites, but no luck finding it.

Pivot.jpg
 
You could have a slight up-curved warp on your scale to tighten onto the blade. Just have to tweek it so it doesn't catch. I dunno... I'm tapping out of this one. Everything I say from here on out is theoretical.. lol.
 
when I made friction folders I used 1/8" pivot barrel with T6 as iirc,
I would call RB Johnson and ask him, I get my folder hardware from him.
 
Last edited:
carbonman said:
I've searched, but can't seem to find an answer on here or general Google search.

I'm trying to build a friction folder with a one sided handle. Chisel ground knife will lay flat on surface of handle. My question is about the pivot...

When using a pivot consisting of a barrel and two screws, what prevents the screws from loosening as you open and close the knife? While waiting for some pivot samples, I'm using a temporary Chicago screw (barrel nut and 1 screw), and it loosens quite easily as I open and close the knife. I'm not using washers as I want the blade to sit as low as possible on the handle. This probably involves some pivot theory, but again, can't seem to find anyone explaining how a pivot should work properly anywhere. Thanks in advance for any suggestions or info.
CM
Click to expand...
What about this ? Make thread IN blade , tight that handle as much you like to blade then ADD nut from other side of blade to get secured from unscrewing.................... ?
fHLVPXi.png

If you want to use pivot you can do this way..........Sand pivot till you get tight both bolts and have proper friction between blade and handle ?
D0IIhbq.png
 
Last edited:
Josh Rider said:
Loctite will prevent it. Otherwise it will come loose. At least that’s what I’ve encountered in my limited experience.
Click to expand...
Perfect! Just what I was looking for and I must of passed those a dozen times looking for them on USA.

Thanks!
CM
 
Natlek said:
What about this ? Make thread IN blade , tight that handle as much you like to blade then ADD nut from other side of blade to get secured from unscrewing.................... ?
fHLVPXi.png

If you want to use pivot you can do this way..........Sand pivot till you get tight both bolts and have proper friction between blade and handle ?
D0IIhbq.png
Click to expand...
Thank you very much for this detailed explanation. More than I was expecting so thank you very much! It has given me some ideas and Ill let you know how it turns out.

Best,
CM
 
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