Lock back knife - sticky movement and galling.

SunOfAtom

SunOfAtom

Joined
Feb 26, 2014
Messages
193
I posted this in the Spyderco forum, but perhaps this forum would be a good place to get some insight and suggestions.

I have a Native 5 G10 (S35VN blade steel) which I purchased new, but has never been smooth like my other knives. Even comparing it to other Spyderco lock back knives I own, the action has always felt sticky. If I hold the lock bar all the way in, the blade swings smooth and free, so I know the issue is not with the pivot or bushings. The issue seems to be a high amount of resistance between the lock bar and the blade.

I disassembled the knife, cleaned and re-oiled it, but it did not make any improvement. I then went in and smoothed out all contact and pivot points by hand (600, 1500, 2500 grit sand paper and then CrOx paste) but this did not make a noticeable difference as well.

Last night I pulled the knife apart, wiped down all surfaces with a clean rag (no alcohol or other solvents) and reassembled, but intentionally did not add new oil so I could get a better feel for the movement while opening and closing. It felt as it always does until about the 10th cycle, when it immediately developed a hard spot in the movement. I pulled it apart and saw that the lock bar and blade are galling:

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Does this seem like unusual behavior? It seems to me that these parts should be hard enough to not begin galling under such a small amount of use. Could this explain why there has always been a high amount of felt resistance when opening or closing the knife?

I sanded down both pieces, and it appeared that metal is being pulled off the lock bar and sticking to the blade. The blade quickly returned to smooth, but the lock bar was left with tiny grooves or holes where the metal is gone. I reassembled and tried it again with the same exact same results.

Any thoughts on why this could be happening?
 
Had the same thing happen with a new Police i bought, sanded it out a bit and was good to go. Fit on the lock is a bit rocky now but its smooth.
 
I would guess the problem is not really galling, but it is the same thing that a sticky titanium lock does and it is because the blade is very hard and the lock bar is not. It is possible that the heat treat on the lock bar is botched and it is too soft causing it to stick onto the blade because it forms too much to the grind marks.

I could be entirely wrong, though, and would greatly appreciate confirmation or correction.
 
I would have to agree with dkb45 on this one, it seems as though the extreme hardness of the S35V steel is just too much for the lockbar to handle when they slide against one another. Perhaps a new lockbar heat treatment would help, but that might also change the dimensions of it a bit, so I'd say a new lockbar of appropriate hardness would probably remedy this issue...but it seems like something Spyderco should address, not the end user.

As always this is just my opinion...but to me it's the most logical explanation
 
I would say Spyderco would fix this if you sent it in. If it's not functioning properly that's on them. That being said I love messing with mine too. I took a Dremel to a sticky one before. Mine rolled good on the detent ball but when it came off the ball and onto the Ti it was sticky. It helped a little but I ended up sitting for a couple nights and at that sticky spot I pushed the lock bar against the blade tang with my thumb and just moved the blade back and forth few hundred times and it went away. I'm not sure about heat treat. Things happen and anything production runs a risk of those things but I assume those are thrown in a steel basket by the 1000's and shoved into an oven, so unless you got the one picked up off the floor idk. I love this style of knife and own a lot of different ones and some open like butter and some don't. I haven't had an edc not break in yet though at this level.
Sometimes I'll torq the pivot screw tight and open and close 50 times then let it back to normal and that helps too with the pivot bushings. Anyway if sanded try just squeezing it and putting a lot of pressure where it's tough and see if that works. If not I know it sucks but send it in.
 
Thanks for the feedback guys. It does seem to me that there is something off with the lock bar, which is causing a weird interaction with the blade. I just thought I would check with you guys in case I was missing something. I'll send it back to Spyderco and see what they have to say.
 
A tiny dab of lithium automotive grease on the tang should cure it.
 
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