Liner lock knife inspection

[Ookpik]

What do you guys look for when you inspect a liner lock knife before you buy it? These are the areas I look at:

Fit and finish – Everything should look and fit OK. No rough spots. No gaps where there shouldn’t be gaps. Good surface polish or finish. Edges smooth. Nothing loose (scales, thumb lugs, clip, etc.). None of the screws should be damaged.

Blade edge – The blade should be sharp enough to shave hair from my arm. The edge should be sharpened at a proper angle for intended use. The sharpened surface on one side of the blade should be the same size and angle as the sharpened surface on the other side of the blade (unless chisel ground). There should be no nicks or rough spots on the edge. The point should be sharp, not broken or damaged.

Blade grind – The blade should be evenly ground. Both sides of the blade should look the same. The grind edges (lines) on one side of the blade should line up with the grind edges on the other side of the blade (unless chisel ground). The blade should not be bent or warped.

Blade centering – The blade should be centered between the liners when the knife is closed. The blade should not contact the liners.

Blade position when closed – The edge of the blade should not contact the back spacer. The tip of the blade should not be outside of the handle or exposed when the knife is closed.

Blade closed detent – The detent should hold the blade fully closed. There should be no opening movement of the blade without the detent starting to disengage. The detent should be strong enough to hold the blade shut when you carry the knife, but not so strong as to prevent easy opening. Excessive pivot tension can mask position and strength defects in the detent.

Smoothness of opening – The blade should open smoothly, but not fall open. The pivot shouldn’t be too tight or too loose.

Pivot washers – I prefer bronze washers, but they are harder to use. The bearing surfaces on the inside of the liners must be parallel. If they aren’t, the pivot can’t be adjusted properly. The pivot will be too tight or the blade will have side play. Teflon washers are more forgiving of imprecision. They are softer and have a little give, making up for misalignment.

Blade play – The blade should have no up and down or side to side play when the knife is open and locked. There should be no side to side play when the knife is partially open or open all the way, with the liner lock held unlocked. Excessive pivot tension can mask potential side to side blade play.

Liner lock – The liner lock should fully engage the blade-locking surface when the knife is gently opened. It should sit on the left side of the locking surface so there is room for wear. It should snap into place and feel secure. If the blade is flicked open, the liner lock should be in the same position as when the knife is opened gently. If the blade stop surfaces (stop pin and back of blade or thumb lugs and edges of bolsters, depending on design) aren’t aligned properly, there will be some give as the blade is opened forcefully. The blade will over travel and spring back slightly. The liner will travel farther then when the blade was opened gently. The liner will then be hard to release because it is under pressure.

Basic design – Basic design is a matter of personal preference and taste. This includes the clip, thumb lugs, blade shape, size, etc.

Materials used – For blade steel. I like 154cm or better. As long as good quality materials are used everything should be OK. Titanium, stainless steel, micarta, G-10, carbon fiber, and various woods are good. Materials are mostly personal preference.

So what else do you guys look for? What have I forgot to mention? Am I fussy? Yes. Am I anal? Maybe.

 

[sph3ric pyramid]

First thing I look at is lock engagement, on liner-lockers. Problem is, even if it looks to be constructed properly they can be faulty.

I then look at the ball detent, to see how securely it holds the blade.

Next is usual inspection of fit and finish. One of my pet peeves is a blade that's not perfectly centered within the handle, although it can be user-adjusted to an extent.

 

[OwenM]

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[Gong]

I have a few Liner Locks and have no problems with any of them. What is some particular models or brands that you have found problems with? Or is it just that you might find a problem on one but not most of the knives produced?

 

[Ookpik]

I like to inspect any knife before I buy it. I haven’t seen any bad Chris Reeve Knives (frame lock) or Microtech. I’ve seen a few bad examples of most other makes. However, most knives are OK. I’m just really fussy.

 

[Steve-O]

Ookpik,

A very comprehensive check list to take to the store! You covered all the things I would look at, if I had a store in the area (there are a couple places that carry a few Benchmades or Microtech - but never what I am looking for and definatly no CRK).

I have to take my chances with mail order and, so far, have had good luck. I inspect an incoming knife pretty much as you do and if I did find any problem, I would be sure to return it. So far I haven't returned even one, lucky, I guess. Not to say that I haven't been disappointed by a couple purchases but, it's usually after a period of use.

I do a lot of research before I buy, materials, size, style and design are taken care of before the purchase.

Also, I place much less emphasis on the blade edge and grind. I can think of only one production and two custom knives that I own that didn't benefit from some work - even IF the grind was even. Some of the best knives that I have took a couple hours to get the best out of them.

Am I fussy? Yes.

Great checklist!


Steve-O

 

[Ming65]

I check the position that the liner rests on the tang looking for room to wear, although the best liner locks I own haven't worn noticeably yet.

I open the blade and press down on something hard (that the blade won't damage, like glass) as if doing a hard push cut. I then check and see how much the liner has moved across and if it has jammed (I've had a couple of cheapies do this).

I then gently spine whack and not so gently blade wiggle.

I also ask to look at a few different samples of the same model so I can pick the one I like best.

...and of course check for blade play both ways.

Sharp doesn't bother me because I can make them that way.