Over tightening the pivot on a Large 21.

Capt. Spaulding · Feb 28, 2015

After the first cleaning of my large 21 I noticed that when I tighten down the pivot I can actually tighten it to much making the blade very hard to open. I was not cranking down on it either. I was under the impression that the pivot bushing is supposed to eliminate the possibility of that. This was after a cleaning and I had went into its first cleaning knowing I wanted to keep the washers in order of which side faces the blade and assemble them in the same manner. I ended up mixing up which side was in contact with the blade as well as which way the pivot bushing went in. Just as a side note I noticed the pivot bushing having a different finish on both sides. One was flat and the other more rounded. Anyways, when I reassembled the knife I played around with washer and bushing combinations until I found it to be as smooth as possible. I can still over tighten the blade though. I have heard some can come with the washers slightly thicker than they need to be which causes this. Any input on this would be appreciated. Thanks everyone.

Vaporstang · Feb 28, 2015

http://chrisreeve.com/Sebenza-Assembly

I don't know if this will be of any help to you....

JNewell · Feb 28, 2015

Are you the first owner of the knife? Either way, assuming it's properly assembled, that seems a little out of spec. A trip back to CRK might not be a bad idea.

BellaBlades · Feb 28, 2015

I crank down on all my screws pretty good.
And it is perfect with the lightest tightness or the way I do it with extra pressure. I know I put more pressure on the screws than most would and the blade still free falls but no play of course.
I also use my own allen key that fits tighter than the one supplier from CRK. The bushing does prevent over tightening but in your case. Your washers are a bit too thick.
You need to take the washers to some 2k sand paper quick or the rough side of some black rouge on a strop. Clean them up a bit and you should be all set.
If this is an issue and you dont want to wait a month for CRK to do it. I will do it for you free of charge if you cover shipping and get it done that day.
But please give it a shot if you have the patience and time.
Matt

353 · Feb 28, 2015

BellaBlades said:
I crank down on all my screws pretty good.
And it is perfect with the lightest tightness or the way I do it with extra pressure. I know I put more pressure on the screws than most would and the blade still free falls but no play of course.

Exactly the same with mine, it freefalls with no play whatsoever, even with lockbar disengaged.

BellaBlades said:
The bushing does prevent over tightening but in your case. Your washers are a bit too thick.

I know CRK makes adjustments on the pivot bushing as a final tweek of the knife action, they sand it lightly if it the action is too loose. My thought is that they maybe tok too much of and then the washers get a bit squeezed and now you have to take some of the washers. There are videos on youtube showing you how to do this in a pretty safe way.

kidcongo · Feb 28, 2015

My first 21 came tight. If I went all the way on the screws it would lock. The washers were to thick for the bushing to match. The 5 other 21s I have could all be tightened down all the way right away. The odd one seems to slip out the door like that. If you strop the washers you will slightly reduce their thickness, which will allow you to tighten down all the way.

Go easy!

Ajack60 · Mar 1, 2015

I've lightly polished the washers, not to the point of the whole washer being honed, just the high spots on the washer. The other thing I've done on re assembly is to put it back together, snugging all the screws, tight down on the back screw, leave the stop pin screw snug and tighten down on the pivot. It has worked for me on one of mine that was difficult to open.

Capt. Spaulding · Mar 1, 2015

Thank you everyone for the replies. I forgot to mention that the blade would free fall when I first got it. I am going to take it apart again and flip the washers as well as the pivot bushing and see if I can get it to free fall again. I'm almost certain I have them in the same way from the factory though. I am not really wanting to sand and strop the washers though. Maybe if I had a strop already, but I can't buy one right now. Plus I don't want to take to much off and ruin them. Thank you for all the good info everyone and I will give you guys a update after I mess with it for a little bit and see what exactly is happening.

lumpy grits · Mar 1, 2015

The smaller dia washer goes on the lock-bar side ONLY.
May sure your not pinching a washer-It's easy to do.
LG

Krissig12 · Mar 1, 2015

You need to take a little bit off the washers. My first small 21 came like this as well, but not quite as bad.

Now it's perfect, I can tighten it down all the way and still have a free swinging blade. It's also play-free, which is important because it means I got it right and didn't take too much off.

You have to be careful about that

GronK · Mar 1, 2015

Krissig12 said:
You need to take a little bit off the washers. My first small 21 came like this as well, but not quite as bad.

Now it's perfect, I can tighten it down all the way and still have a free swinging blade. It's also play-free, which is important because it means I got it right and didn't take too much off.

You have to be careful about that

OP says the problem happened after cleaning, it was ok before. I'd bet there's a pinched washer or other anomaly caused by disassembly.

Krissig12 · Mar 1, 2015

GronK said:
OP says the problem happened after cleaning, it was ok before. I'd bet there's a pinched washer or other anomaly caused by disassembly.

Did OP try cranking it down before disassembling it? If not, then we'll never know for sure whether the problem was present from the factory.

But a pinched washer is a definite possibility. I think we need some pics

Capt. Spaulding · Mar 1, 2015

Krissig12 said:
Did OP try cranking it down before disassembling it? If not, then we'll never know for sure whether the problem was present from the factory.

But a pinched washer is a definite possibility. I think we need some pics

I never cranked it down from the factory so I do not know if it is from something that happened during disassemble/reassemble or if they just left the screw loose from the factory.

What do you need pics of?

jheredia · Mar 2, 2015

I think whats happening is pivot bushing CRKs are fit by hand at the factory, some are looser and others are tighter since its all based on the assembler's feel. The screws are then screwed at a certain torque which a lot of times is much lighter than what people use to tighten their screws. This means that if the pivot bushing and washers were fit very tightly with little movement at the specified torque, then when reassembled by the owner during maintenance its possible to over-tighten. Its happened on a few of my sebbies. You can either tighten the pivot screw a little less tightly or send it in for a re-fit. They will basically, as others have said polish off a little material off of the washers to make them a little thinner and fit more flush with the pivot bushing. The fit really varies a bit between sebenzas in my experience, some of mine were loose and had a bit of movement in the pivot and other were stiff, but what I consider play many people will consider flex. I actually use a lot of force to check for side to side play as well as take off the lock bar pressure, I prefer to feel no movement at all and let the washers polish naturally during the life of the knife and smooth up. But anyway I hope that helps!