How to adjust the pivot on a large Spyderco back lock

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maximus83

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Nov 7, 2011
Messages
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Having trouble adjusting the pivot on a large back lock folder--a Spyderco Chinook 3--to get a good balance between ease of opening/closing, and the amount of blade play.

Any tips from the forum on next steps to try?

Background:
  1. The folding mechanism locks up strongly, the blade is perfectly centered between the handles, and I don't think there's any safety or malfunction issue here. I just cannot get an optimal adjustment that lets you easily open/close the knife, AND eliminate blade movement at the same time.
  2. What I've tried: adjusting the the 2 pivot torx screws in relation to each other. Tried various combinations of tightening one a little more than the other.
  3. Wondering if I need to go to something like blue loctite, put it on the pivot screws.
 
Tighten until the blade has minimal side to side play then check the opening tension, it should flick about half way open and if you add a wrist snap to the flick it should open all the way.

The opening action should be slightly stiff... never gonna be silky smooth or open like its on bearings.
 
Jason, makes sense. I can adjust to that, easily. I think it's partly my expectations, I have other spydie back locks that I can flip open easily AND eliminate blade movement, without constant re-tightening. But those blades aren't as big as this one.

If I continuously have an issue with the pivot tightness working its way loose after some usage (this has been an issue), should I add loctite to the pivot screws?
 
maximus83 said:
If I continuously have an issue with the pivot tightness working its way loose after some usage (this has been an issue), should I add loctite to the pivot screws?
Click to expand...
I just did this to fix a knife where the pivot screw would not stay put. I used blue.
 
I have some Spyderco lock backs that flick with ease and others that require the thumb to be used until it locks. Most will always get better with use though.
 
Problem solved. It took both things: tightening it a bit more than I originally wanted to, and then using blue loctite. After some use, now it flicks open smoothly with no blade play, and the pivot screw stays set. It doesn't CLOSE quite as easily, but that's not as important to me.
 
A touch of play doesn't bother me on a pocket knife.

If it were a pivot(bearing) that spins for hours and supports, say, my body weight then I go for first of all a REAL bearing (close precision tolerances etc.) and then a zero play and perhaps even the very slightest pre load on the bearing adjustment.

I am glad you achieved victory. If the pivot gets sick again it might be worth disassembling the knife to see if there might be some chip or thread of material imbedded in the pivot area causing things to bind (the "doesn't CLOSE quite as easily").
 
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