ZT 0560 lock geometry

[Silvanus]

So, I haven't used my 0560 much since I got it back from warranty service, its taken a back seat to my XM-18 and CRKs. The warranty service I sent the knife in for was a blade crack, so the blade was obviously replaced. I was looking at the lockup and noticed that the interface between the tang and the lock bar is at an angle. The black in the gap there is shadow, the only contact is on the far right side of the lock bar. I don't remember the lock interface that way before I sent it in for warranty. Then again, I never really looked at it. I checked for lock rock and there is movement up and down. Lockup is at about 40% so there is only about 1/16" X 1/32" of total contact between lock and blade. I looked at my other Ti frame locks, they are all flush with full length contact. Is this at all normal for an 0560? If so, Ill leave it as is but it seems like a poorly ground blade. What do you guys think? On another note, if I adjust the pivot so the blade is centered there is a huge amount of side to side play and the lock rock gets a little worse. If I remove all the side to side play, the blade is nearly touching the lock side. Any suggestions?

 

[TEFL0N_D0N_81]

I've yet to see a Ti frame lock where the lockbar fully engages the surface of the blade tang. It's always a small area. That means it's never level, and always engages at an angle. In your case, the angle seems more than usual, but doesn't change the fact that the contact isn't flush anyways. I'd use the crap out of it and see if it's worth replacing.

 

[Silvanus]

The lock interface on my Hinderer and Sebenza are flush and level. But if it is normal on other knives I wont worry I guess.

 

[Scurvy092]

Menovade and I had an extensive discussion on this one time. I think it is just a personal decision and doesn't appear to make much of a difference either way. If you look at the tang of the blade while closed, you can see what part of the lock bar is making contact. I have knives just like the one pictured and knives that make full engagement. Doesn't appear to make a difference.

The problem with making the whole lock bar line up is that it has to be perfect or else you will get lock rock or binding. Also if the engagement is too low on the lockbar, it can cause issues. That's per Menovade.

 

[RevDevil]

Here is some interesting reading that must be done in order to understand the concept of liner/integral locks:
http://emersonknives.com/blog/emerson-knife-anatomy/
It does not simply apply to Emerson knives, but it applies to all knives with this lock type. Remember, Emerson isn't a newb to this, he's been making knives for about 30 years give or take.

Here is a little snippit, the same principle can be applied to integral locks:

Liner Locks are comprised of a three point contact system. The three points are:

1. Point where the blade contacts the stop pin.

2. The center point of the pivot bolt.

3. The point where the liner contacts the bottom edge of the blade ramp.

Note: There must be an angle between the blade lock ramp and the face of the liner lock to create the three point lock structure and relationship. The face of the lock and the face of the spring are not parallel.

Cheap Chinese imports and others who do not understand the mechanics of the liner lock system may think that the lock face on the blade and the face of the liner lock should be parallel, face to face, with full engagement of the lock face against the back of the blade. They are incorrect. As both aerospace mechanical Engineer and the third knife maker in the world to use the liner lock system almost thirty years ago, and having made several thousand custom knives and several hundred thousand production knives I assure you that I know of what I speak.

The lock interface on my Hinderer and Sebenza are flush and level. But if it is normal on other knives I wont worry I guess.

Nope. The 3 XM18 knives i have follow this 3 point system, you might look again, closer with magnification and the back of the blade where the lock bar actually makes contact.

 

[BellaBlades]

The blade play is not normal. Nor is a non centered blade with the bearing set up, unless the blade is totally out of whack.

That lock up is rock solid, Look at a strider it looks the same. Total flat contact can mean blade play often.

 

[bodog]

I have a 0560CBCF, lockup at about 40 percent. The lockbar and lockface surfaces touch throughout the entire 40 percent with no blade play at all in any direction. To be fair, that was before I had to send it in for the same problem, cracked blade at the thumbstud. I should be getting it back in a couple of days, Friday at the latest according to them. I'll let you know if they screwed up the lockface on mine as well. Sounds like that's what happened, they screwed up the lockface grind.