21: Blade play when lockbar is disengaged

[Evany]

My large KnifeArt CF 21 has a tiny amount of side to side blade play when the lockbar is disengaged. Once the knife is fully open and locked, it's very solid. Pivot and Stop screws are tight. Is this normal? I've never noticed blade play anywhere on any of the many 21s I've handled. This knife was very stiff to open when new. I used it that way for about a year and then recently took it apart for a clean and lube. Now it's very smooth and easy to open, blade drops free when the lockbar is disengaged.

 

[Clem Fandango]

I haven't ever had that on 21 or 31. That said, I haven't really had one that I would describe as very easy opening or closing.

Have you tried tweaking the pivot?

 

[353]

I can think of two reasons.

1 - The washer on the CF side has wore into the CF.

2 - Your washers have somehow been wore down.

Have you tried to tighten the pivot?

 

[Evany]

353--worn washers is a possibility. Since it was pretty hard to open when new, it's possible that the friction of opening and closing wore them down just enough. I have the pivot and stop sleeve tightened just barely further than snug. Wouldn't want to go further there. Maybe I'm overthinking it, since it doesn't move at all when locked.

 

[Jsega51]

My large 31 has just a tiny bit and so does a barely used 21 that I recently received. Like you said, it’s not there at all when I’m not holding the lock bar open so it doesn’t concern me.

 

[Honed_Edge]

This is not new. I've seen it discussed several times. The consensus was always the same. Some peoples 21 is rock solid and the other group has a little wiggle if holding the lock. I have had tight and slightly tight from out of the box. I have never had one free drop or "lock wiggle" (insert locking term) when new. After maybe six months of use many are only a tiny bit tight or even loose. It's then that some get the very tip to wiggle. A lot of it is in your meaty fingers. Sit it on a table and do it. It's hard as there is no good way to hold the knife. The tip moves a mm or two. Think how little that is in the lock region. Surprisingly, I have two knife arts that are still tight after a lot of use.

(Whispering) I think crk washers are a crap shoot. I know many of mine were not flat in that they had high spots. They were not warped, but punching or something left artifacts.

 

[XL883N]

You wouldn't use the knife with a disengaged lock bar so why would this matter?

 

[Evany]

It wouldn't matter at all if that was they way the knife was designed. However if it is an early indication that the knife is out of spec, then it matters.

 

[Heirphoto]

Is it truly side to side or is it front to back? My Damascus large 21, with the lock bar released has just a hint of play but not side to side. I can just make it move fore and aft as if these is a few thou clearance between the pivot, bushing and blade letting the blade move forward or backwards (or up and down) as that clearance it taken up between pivot and bushing diameters and/or bushing and blade hole diameters, but no play left or right as that is controlled by the washers.

Edit: Actually any play like I have must be between the blade hole diameter and the pivot bushing outer diameter as once assembled the pivot bushing itself is locked tight with scale pressure when the pivot screw is tightened so it should neither rotate or be able to move axially even if the pivot bolt itself was undersize.

 

[ShadyMethods]

I wouldn't worry about it too much. It never really affects anything. I have 3 21s and 2 of them have that slight bit of play with the lock held. You can't normally adjust it out because of the pivot bushing. As long as it is just a tiny amount, you'll be fine.

 

[Evany]

Just a tiny amount. It may have always been there, I just never noticed it before.

 

[WValtakis]

Just a heads up, Chris always said there was .0005" clearance on the bushing pivots to allow room for grease. If assembled dry or with a light oil instead of grease there is a barely perceptible amount of horizontal play if you really check for it.