Dual Pivot Screws

E

Elefantener

Joined
Jul 1, 2014
Messages
187
Well I was adjusting my Cold Steel Recon 1's pivot screw (single screw) and got it perfect (it was very loose). I though I would do the same with my BM 2750, this was a bad idea. I adjusted it and the whole auto feature went to _____, the blade was limp and would not fully go into battery. Freaked me out, so the next day I borrowed another wrench from my neighbor. I messed with both screws and got it back to the original settings, thankfully. But this makes me wonder, why are dual pivot screws used, what purpose do the serve over using a single pivot screw?
 
Hard to back a screw out of something that just spins with the screw when you turn it. Two screws provides a counter force which is useful especially with loctite on the screws.
 
In my experience it's possible to overtighten any pivot whether there are screws on one or both sides. I suppose having both sides be adjustable might make it marginally easier to tweak to exactly the right tightness, but I don't know that it gives it any major advantage.
The only exception to this is pivots with a bushing system, like the one found in Sebenzas, which cannot be overtightened since pressure is not being directly applied to the rotating portion of the pivot.

Edit: it's important to note that single-screw systems require a pivot that has a flat side, such that it can't spin freely in the hole. This is the setup found in most Benchmades and Emersons, for example.
 
Centering a blade while getting the exact tension you want always seems to be much easier on a two screw system in my experience.
 
amg137 said:
In my experience it's possible to overtighten any pivot whether there are screws on one or both sides. I suppose having both sides be adjustable might make it marginally easier to tweak to exactly the right tightness, but I don't know that it gives it any major advantage.
The only exception to this is pivots with a bushing system, like the one found in Sebenzas, which cannot be overtightened since pressure is not being directly applied to the rotating portion of the pivot.

Edit: it's important to note that single-screw systems require a pivot that has a flat side, such that it can't spin freely in the hole. This is the setup found in most Benchmades and Emersons, for example.
Click to expand...

Except for the Kershaw Emersons.
 
amg137 said:
You could be right, but IIRC my CQC-7K and 8K both had a flat section when I disassembled them. I certainly had no issues with freely rotating pivots either way.
Click to expand...

The 1k does not, and I couldn't get the pivot screw out because the whole thing was spinning freely.
 
The batteries fell out of the knife?? :confused:

Not all pivot assemblies are a simple male to female (nut and bolt). Look at the Chainring pivots for example as used on Strider and Hinderer knives. Another example is the Sebenza, a bushing pivot; 2 male bolts and a female threaded piece in the center. When tightened properly, you have a snug pivot while providing smooth opening and closing.
 
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