Advice on a faulty liner lock

[houseofleaves]

Hi guys, apologies as this may well be an daft question but I've never taken apart a knife before.

I have the pictured Harnds Viper, is a cheap Chinese knife & arrived with the liner lock not fully engaging meaning that with a little force it disengages. My question is, will a bit of work with a metal file sort this out? & is it simple enough to take apart? I imagine it's just blade/washers/liners. Anything I should watch out for?

Any input much appreciated.

Cheers

[AdmSlc]

It looks like it has nice early lock up. It probably has a carbide issue which is why it is not locking to the knife blade. It could also be that the angles are too sharp on the blade and lock bar.

[rebel]

Isn't it now UK legal?

[AdmSlc]

I'd be careful filing away too much material as this will create vertical blade play.

[SAK Guy]

Yes but go slow, don't change the angle of the lock tip (if correct) and remember, you can't put metal back resulting a loose lockup.

[houseofleaves]

It looks like it has nice early lock up. It probably has a carbide issue which is why it is not locking to the knife blade. It could also be that the angles are too sharp on the blade and lock bar.

Excuse my ignorance Adm but what would a carbide issue be? Looking at it closely the angle of the blade where it meets the lock does look pretty sharp..

Isn't it now UK legal?

Potentially! 😉

[houseofleaves]

Yes but go slow, don't change the angle of the lock tip (if correct) and remember, you can't put metal back resulting a loose lockup.

Cheers SAK, I have nothing to lose so may just have a go at it..

[dks]

yes, file the lock bar gently (microns) and make sure you remember where the parts go when you take it apart (photograph each step).

You can also try cleaning it a bit...

[AdmSlc]

It looks like it has nice early lock up. It probably has a carbide issue which is why it is not locking to the knife blade. It could also be that the angles are too sharp on the blade and lock bar.

Excuse my ignorance Adm but what would a carbide issue be? Looking at it closely the angle of the blade where it meets the lock does look pretty sharp..

Isn't it now UK legal?

Potentially!

Many knife makers have carbidized lock bar faces. Too much or too little can create too sticky/ lose lock up. Seems more common on higher end knives /titanium

[houseofleaves]

Thanks for the advice/info guys. I'll give it a go & see what I can do.. Good or bad..! 😀

[SteveC]

Before I filed anything I would try to bend the lock over slightly to get later lockup.

[houseofleaves]

Before I filed anything I would try to bend the lock over slightly to get later lockup.

Thanks Steve, will give it a go

[tattoosteve99]

Don't file it yet. I used a trick on one before I filed it and it worked. Use a regular graphite pencil and rub the pencil point on the lock bar and blade. This will lubricate the bar. Try that first before you file it. 

[pingu]

I agree with the don't be hasty previous comment.  For the amount of engagement shown I'm surprised that it doesn't take a *lot* of force to break the lock.  ISTM from the picture the lock-bar face isn't *exactly* perpendicular to the axis of travel.  Is there any blade play?  I'd suggest loosening the pivot and playing about trying to find a lock-up sweet spot.

There is picture of parts here...
https://www.fasttech.com/forums/-/t/1398538

And while looking at that site maybe cut your losses and consider this...
https://www.fasttech.com/p/2142900

Unbelievable value and quality control, at least in my sample.