Lock up % vs. Detent strength

MajorHarryFace

MajorHarryFace

Joined
Nov 1, 2014
Messages
63
Just got my ZT 0561 and it has 30-40% lock up with a very weak detent. The blade will unfold with a very light 'shake'.

Is there a way to strengthen the detent? Is a weak detent expected with such early lock up? Should I send it back?

Thanks,

Paul
 
Mine is very similar and much weaker detent than my 0562 or 0801 but i had some customization done and missed the boat for warranty work. Id send it in if you feel like its not quite right. Keep us posted.
 
Sending it back is the best way to get it fixed if you don't like the detent strength. You can bend the lockbar in a little yourself, as many here do, but you run the risk of damaging the knife and voiding the warranty.
 
I have two 0560s. The lockup is 50 percent on one and about 35 percent on the other. I can't detect any difference between them in the detent.
 
dgebler said:
Mine is very similar and much weaker detent than my 0562 or 0801 but i had some customization done and missed the boat for warranty work. Id send it in if you feel like its not quite right. Keep us posted.
Click to expand...

Thanks for replying. Please share what kind of customization you had done. Customization is my favorite.

Silvanus said:
Sending it back is the best way to get it fixed if you don't like the detent strength. You can bend the lockbar in a little yourself, as many here do, but you run the risk of damaging the knife and voiding the warranty.
Click to expand...

If you know, when you send it in, do they bend it or how do they fix it?

Twindog said:
I have two 0560s. The lockup is 50 percent on one and about 35 percent on the other. I can't detect any difference between them in the detent.
Click to expand...

Thanks for that info. Do yours have weak, medium or strong detent?
 
Really the only way to fix a weak detent is to bend in the lockbar so I'm sure that's what ZT will do.
 
The detent on both my 0560s -- one at 50 percent and the other at 53 percent -- are both fairly strong. I cannot shake the blade open.
 
Bending the lockbar is the only way to adjust a detent that is not set to your satisfaction. At least without some serious mods. I will however disagree that it would void your warranty. Kai has one of the best warranties in the business. In fact i would venture to say the best. The only way I know of to void your warranty with them is if your actions cause damage to the knife and it needs repair due to you breaking the knife by modifying it. But i have NEVER heard of them denying warranty because someone took the knife apart and made and adjustment. And I know this from personal experience.

If you do decide to take it apart you need be a bit careful. Sometimes these knives have some loctite on the pivot and handle screws. If they dont move easily do not try and force them. You run the risk of slipping and scratching the knife and/or stripping the bolt head. The only way to free the screw is the application of heat via a soldering iron to soften the grip of the loctite. Also when adjusting the lockbar small adjustments are all that is needed. You may not even be able to visibly tell you bent the lockbar. And you DO NOT want to overshoot it. Bending the lockbar to the point of yielding (where it wont return back to the point it started) is not something you want to do repeatedly. So its best to make small adjustments more than once than overshoot it and have to bent it back. As to the lock engagment your knife may have had a sticky lock in which the lockbar tension may have been reduced. If you knife does not have lock rock you wont notice a huge difference in lock engagement unless you flip it extremely hard. But its not like you will go from 30-40% lockup and go to 75%. I personally wouldnt bother sending it back for such a minor adjustment but then again I tinker all the time and am confident in my ability to do such a job. And I trust that I know how I would want my knife set up and dont know if that can be translated to another person who isnt familiar with my tastes.

The last thing that I think needs mentioning is that of the perceived smoothness of the knife. Many people have this misconception that a bearing flipper is smooth operating because it has bearings. This isnt really the case. Bearings increase the speed, are self centering (when properly machined) and do reduce friction in the pivot but it increases speed, not so much the smoothness that can be felt. That is more the result of lockbar pressure. increasing the tension will certainly increase the detent strength but that resistance is now going to be directly applied to the tang of the blade as it rotates. If you love that feeling of the blade just free falling back into the handle under its own weight you must understand it may not do that anymore or at least not as easily.
 
If the detent ball is sitting shallowly in the detent hole of the blade, detent strength can be increased by making a larger hole. It's an easy tweak to do with a ball nose end mill and drill, but of course it probably voids your warranty.
 
PURPLEDC said:
Bending the lockbar is the only way to adjust a detent that is not set to your satisfaction. At least without some serious mods. I will however disagree that it would void your warranty. Kai has one of the best warranties in the business. In fact i would venture to say the best. The only way I know of to void your warranty with them is if your actions cause damage to the knife and it needs repair due to you breaking the knife by modifying it. But i have NEVER heard of them denying warranty because someone took the knife apart and made and adjustment. And I know this from personal experience.

If you do decide to take it apart you need be a bit careful. Sometimes these knives have some loctite on the pivot and handle screws. If they dont move easily do not try and force them. You run the risk of slipping and scratching the knife and/or stripping the bolt head. The only way to free the screw is the application of heat via a soldering iron to soften the grip of the loctite. Also when adjusting the lockbar small adjustments are all that is needed. You may not even be able to visibly tell you bent the lockbar. And you DO NOT want to overshoot it. Bending the lockbar to the point of yielding (where it wont return back to the point it started) is not something you want to do repeatedly. So its best to make small adjustments more than once than overshoot it and have to bent it back. As to the lock engagment your knife may have had a sticky lock in which the lockbar tension may have been reduced. If you knife does not have lock rock you wont notice a huge difference in lock engagement unless you flip it extremely hard. But its not like you will go from 30-40% lockup and go to 75%. I personally wouldnt bother sending it back for such a minor adjustment but then again I tinker all the time and am confident in my ability to do such a job. And I trust that I know how I would want my knife set up and dont know if that can be translated to another person who isnt familiar with my tastes.

The last thing that I think needs mentioning is that of the perceived smoothness of the knife. Many people have this misconception that a bearing flipper is smooth operating because it has bearings. This isnt really the case. Bearings increase the speed, are self centering (when properly machined) and do reduce friction in the pivot but it increases speed, not so much the smoothness that can be felt. That is more the result of lockbar pressure. increasing the tension will certainly increase the detent strength but that resistance is now going to be directly applied to the tang of the blade as it rotates. If you love that feeling of the blade just free falling back into the handle under its own weight you must understand it may not do that anymore or at least not as easily.
Click to expand...

Thanks for the very useful info and what exactly is lock rock?
 
MajorHarryFace said:
Thanks for the very useful info and what exactly is lock rock?
Click to expand...

The worst thing ever. It's when your blade has up and down play in the locked position, due to the lack of proper contact with the lock and the blade's tang or contact in the wrong area. Low lock bar pressure is one of a few factors that contribute to lock rock.
 
Blade and Flame said:
If the detent ball is sitting shallowly in the detent hole of the blade, detent strength can be increased by making a larger hole. It's an easy tweak to do with a ball nose end mill and drill, but of course it probably voids your warranty.
Click to expand...
I would never do this. If you drill the hole even a fraction too large you can have play in the closed position that won't be able to be tuned out. At that point you need a bigger detent ball and you are back to where you started. Not to mention that if you get the detent ball seated too far into the blade you can rip it out when opening.
 
Bending a lock bar to fix poor retention in the closed position is like using a crowbar instead of your hands to fix a refrigerator drawer that won't close.

The most common reason for weak retention is incomplete seating of the ball in the hole due to pocket lint. If not dirt the next reason is a loose pivot and/or frame. Tighten it up. However, If it has poor retention when new, send it back, because either the alignment is wrong, ball/hole is mismathched or the design sucks.
 
brownshoe said:
Bending a lock bar to fix poor retention in the closed position is like using a crowbar instead of your hands to fix a refrigerator drawer that won't close.

The most common reason for weak retention is incomplete seating of the ball in the hole due to pocket lint. If not dirt the next reason is a loose pivot and/or frame. Tighten it up. However, If it has poor retention when new, send it back, because either the alignment is wrong, ball/hole is mismathched or the design sucks.
Click to expand...

The knife is brand new, everything is tight, blade centering is perfect, 35% lock up with no lock rock. Using magnification, I can see the ball drop into the hole. So is the ZT 0561 is a poor design?
 
brownshoe said:
Bending a lock bar to fix poor retention in the closed position is like using a crowbar instead of your hands to fix a refrigerator drawer that won't close.

The most common reason for weak retention is incomplete seating of the ball in the hole due to pocket lint. If not dirt the next reason is a loose pivot and/or frame. Tighten it up. However, If it has poor retention when new, send it back, because either the alignment is wrong, ball/hole is mismathched or the design sucks.
Click to expand...

This is correct. The issue will be with the detent ball/hole. I would not mess with that, you should send it back to KAI and have them fix it.
 
MajorHarryFace said:
The knife is brand new, everything is tight, blade centering is perfect, 35% lock up with no lock rock. Using magnification, I can see the ball drop into the hole. So is the ZT 0561 is a poor design?
Click to expand...

There can be small variances in the ball or hole that do not allow for a proper 'detent' so the ball falling in the hole does not mean all will be good. They need to both match so that the ball stays in the hole until the desired amount of force (detent) gets it out. If you have an improperly machined ball or hole, it will effect your detent.

When your knife is closed, is it easy to move the blade side to side?
 
brownshoe said:
Bending a lock bar to fix poor retention in the closed position is like using a crowbar instead of your hands to fix a refrigerator drawer that won't close.

The most common reason for weak retention is incomplete seating of the ball in the hole due to pocket lint. If not dirt the next reason is a loose pivot and/or frame. Tighten it up. However, If it has poor retention when new, send it back, because either the alignment is wrong, ball/hole is mismathched or the design sucks.
Click to expand...

I think you should contact the majority of modern production facilities and them know they have been correcting weak detents all wrong for years. Kai, begg knives all have simply tweaked the lockbar on knives I have sent in for such issues. I know for a fact strider as well as many others do this too. Poor seating due to lint isn't the issue on a new knife out of the box. All lock bars are set by hand and all they do for poor retention is adjust the tension. Even with a perfectly executed detent it won't hold if the bar is set too weak. Do you really think instead of applying a tiny bit more pressure that they rip parts out to compensate? They don't remove or replace the ball, or enlarge the hole. That causes too many problems. What you are suggesting is that they turn the planet to screw in a light bulb.
 
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JR88FAN said:
That would not be the 'correct' way to fix a detent issue, it should be done by matching the hole/ball to whatever KAI thinks is proper amount of detent.....
Click to expand...

Where are you getting this information man? Production knives are not custom. And even custom makers in most cases use 1 single size detent ball for any given model. Then they drill the same size hole in each blade for that hole. The lock bar engagement is set by how the lock face is ground and how much material is ground off. The lock pressure is then set by bending the lockbar. Now if they go and set the lockbar and find that the detent isnt grabbing hard enough they dont go for the drill bit or reamers and enlarge the hole. Especially if that work is within spec. Quite frankly I am surprised you are so resistant to this pretty basic knowledge of how knives are made. Lets say they check the detent ball and it is set into the lockbar properly. Then they check the hole in the blade and it has proper seating but its still not grabbing good enough. There is only one option to fix that. And that is the most minor subtle adjustment to the lockbar pressure.

If they drill the hole in the blade too large the detent ball will not hold the blade in the closed position and you will have in and out play because the ball is smaller than the hole. And most times you can only dial that slop out if the edge of that ball can be forced right up against the wall of the hole in the blade or else you get annoying blade wiggle when closed. And even if you go and re drill the hole for a detent ball to sit further into the blade if you dont have sufficient lock bar pressure to push the ball into that larger hole further you STILL wont gain any traction. Production companies build things within certain specs. They drill a hole to size and use the same size ball for a given model. They trust that those two areas will be manufactured within spec. Then they set the lockbar to have sufficient detent strength without causing too much resistance as the blade turns. I think people might be really overthinking this. We arent talking huge amounts of adustment hear. You can increase the strength of a detent by adjusting the lockbar tremendously and in most cases you cant even visually tell that the lockbar position was changed. And I implore you to ask any production company on how they correct weak detents. You will 9 out of 10 times get a response that they tweak the lockbar. Drilling holes bigger and replacing detent balls 1 takes too much time and 2 wont provide any more desirable results if you still dont have sufficient pressure to keep that detent in the hole.
 
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