Why did the pivot stiffen up on my Paramilitary 2 after cleaning and lubing?

I've had a PM2 that came as smooth as silk, but after 3 days it became very hard to open, and I even had to push the blade down to close it.
I had never used or cleaned it, only opened and closed it several times. Sent it back, and it has been very smooth since.
I've heard a few having this similar problem with the PM2, but I have never had this problem with the PM1 or heard of any that have. I wish the handle shape was the only thing that was changed on the PM.
 
JNewell said:
WD-40, however, is not a lubricant.
Click to expand...

In my self-appointed role as Bladeforum's primary WD-40 advocate :), it is worth noting that WD-40 contains mineral oil, which is a light lube.

There may be "better" lubes, but mineral oil does the trick. "Better" being very subjective, especially when cost is factored in.

But I never lube any of my knives, and have never seen the need to. They open smoothly and, depending on the design, many or most will flick open like butter. I guess that lube is not a bad idea, but I've never found the need. JMO. I will sometimes blast a pivot with WD-40 if its getting dirty, but thats about it.
 
When my para got gummed up last week, I adjusted the pivot a few times and it would work fine. Then hours later it wouldn't. When I finally took it apart the washers had a clear sticky film on them. So loosening screws would have never been a permanent fix. I wiped them off put about 5 pins sized dots of CRK grease on each washer and like I said it's like new. I'm sure it would have been fine without the grease. Have you tried sticking the knife under a running faucet of hot water for about 10 minutes. That's worked on a few of mine in the past when I couldn't take the knife apart.
 
That is actually not an odd question at all. My short answer, which I think is consistent with others' experiences, is that the PM2 is sensitive to adjustment of BOTH. My own preference is to do this:

1. Tighten the pivot all the way, with the stop pin screws loose (only tight enough to retain the stop pin in the holes in the liner). If the blade binds, loosen the pivot screws to obtain the desired action with the blade. Secure the screws with a little blue Loctite (apply before tightening, make sure threads are clean).

2. Snug down both stop pin screws and re-check the blade action. Tighten stop pin screws as far as possible without adversely affecting blade action. Use Loctite on these as well (apply beforehand; use blue #242; clean threads).

Hope this is of some help.

NCBirdHunter said:
Thanks to all of you for the responses. Here's a follow-up question for you...

If I want to try to loosen the blade up a bit myself, should I adjust the pivot screw or the blade stop screw? I know that seems like an odd question because the obvious answer would seem to be to adjust the pivot screw (like one would on a liner lock). However, if I understand the Bushing Pivot System correctly (and I admit I may not), the pivot screw is supposed to be tightened down all the way and it is not designed to allow for minor adjustments to the blade tension (this would seem to be reinforced by the fact that tightening the pivot screw on a PM2 will not eliminate blade play, even if the pivot screw is tightened as much as possible). Also, I have read posts that indicate loosening the blade stop screw will aid in fixing a sticky compression lock and that a byproduct of that adjustment may be freer blade movement.

Has anyone adjusted the blade tension on their PM2 and, if so, which screw did you adjust?
Click to expand...
 
I am not a WD-40 basher, trust me. I have been using it as a surface protectant on firearms for more than four decades with absolutely no bad results whatsoever. :)

Further, I wouldn't disagree that it leaves a very light lube coat behind, but that's not its purpose. And, I do agree (and mentioned above) that many people run this and other knives dry with no bad results, so I think you and I are somewhere between 99% and 100% on the same page on all this. :thumbup:

powernoodle said:
In my self-appointed role as Bladeforum's primary WD-40 advocate :), it is worth noting that WD-40 contains mineral oil, which is a light lube.

There may be "better" lubes, but mineral oil does the trick. "Better" being very subjective, especially when cost is factored in.

But I never lube any of my knives, and have never seen the need to. They open smoothly and, depending on the design, many or most will flick open like butter. I guess that lube is not a bad idea, but I've never found the need. JMO. I will sometimes blast a pivot with WD-40 if its getting dirty, but thats about it.
Click to expand...
 
The Para-2 has a pivot bushing that has threaded female holes on either side (you sound like you already know this). The blade tang has a hole and slides over the pivot-bushing. The washers sandwich around the blade on either side (around the bushing - up against the tang if I remember correctly I'm doing this from memory since it's been over a week since I took my digi-satin one apart for a cleaning/sharpening), and the liners sandwich around the bushing and are up against the washers (one liner is keyed to one-side of the bushing - I want to say it's the non-detent side but again, I'm going by memory). Then come the scales, and the pivot-screws.

Gunk can get into any of the above places and is especially bad when it gets between the pivot and the tang (and that just happens to be a very difficult place to clean without taking the knife apart). If there was dirt between the liners-washers-bushing/blade, then adding a really wet oil could have just washed that gunk down in between the bushing/tang - where it would cause a muddy gunk to slow down the action of the blade's opening/closing.

I take mine apart and use a small bottle of Lucas Assembly lube - it's very sticky, but super slick - I only use a thin layer of it, and it pretty much attracts dirt at the outer parts of the grease, but it seals up the area between the bushing and tang pretty well.

I'm in agreement that you can probably run most folders dry and there really is not a huge need for high-end lube, but I've found that this $4 bottle of assembly lube has solved most of my folding knive's lube-related problems (and a little bit of this stuff goes a long way).

If you don't want to take the knife apart (and subsequently void your warranty), I say soak it in hot soapy water for 10 mins or so and then rinse it (really well) and then blow it out with canned air or a compressor (really well - especially around the pivot area). I'd wager that your problem goes away after that.
 
Did you loctite the pivot screw when you re-assembled the knife? If you use too much on the threads, it will seep through onto the washer and seize up your blade.
 
Well, before undertaking a complete dis-assembly of my PM2, I decided to apply some Ballistol and try simply adjusting the pivot screw (and praying I didn't inadvertently introduce any blade play into the knife, because there was absolutely no blade play in it to begin with). Lo and behold, I backed the pivot screw off about 1mm and the opening and closing action is now perfect (in fact, I think it is better now than it was before all the stiffness started) and there is still no blade play. Hallelujah!

What is interesting is that when I started turning the pivot screw, I did not have to "break" the pivot screw loose from the Loctite that was applied at the factory (which I would have expected, since this was the first time I have touched the screw). The pivot screw just immediately began moving when I started turning it and it didn't require any force at all to unscrew it.

Anyway, all is good now so the "intrinsic enjoyment" of my PM2 has been restored. Thanks to all of you who offered your thoughts and comments. This is a great forum.
 
Last edited:
FWIW, I have found that Breakfree will very significantly weaken/break blue Loctite if you give it some time, so perhaps that's why you didn't encounter any need to break a Loctite bond on the pivot. Then again, maybe it didn't have any. :) I've used Breakfree to weaken the thread locker the SureFire uses on their bezels. In any case, the real thing here is: congratulations and glad for the happy ending. The PM2 is one of my favorite knives. :thumbup:
 
Breakfree CLP is a fine pivot lube. It's a lightweight PAO base oil with teflon and corrosion inhibitors in it, and maybe a small amount of a mild solvent. I could do without the teflon but it's good stuff and won't dry out or stiffen up over time. Like any oil, if you use too much without wiping the excess it will pick up dust and grit from your pockets and eventually form a pasty mush that can slow things down, just use less, if you can see a film of oil then you're probably using too much. There are of course other brands and formulations of CLP, some of which contain solvents and different types of lubricants, all the ones I'm aware of would work fine for a spyderco. Very small changes in pivot tension can have a large effect on how easily the blade swings, generally speaking snug is too tight, I've taken to using teflon tape in place of threadlockers on adjustable pivots, as you don't need to wait for it to set up, and it can be readjusted a number of times before needing reapplication.
 
You must log in or register to reply here.
Back
Top