What's the deal with the linerless (H1 mostly) knifes and up and down blade play?

[Evil D]

This is more of an observation than a gripe, and maybe just looking to see if others have shared the same experience. I spent a solid hour at the local knife shop today going through knife after knife, all different H1 knives so they were all linerless, and EVERY ONE OF THEM had vertical blade play. I probably went through 20+ knives. Is this just lock rock or what? I'm starting to believe the "lower end" back lock knives all suffer from this, because the only back lock I've had that didn't have this issue is my Caly 3 and Centofante 4. Even my Stretch had it (though it did turn out to be defective) and I just received another Stretch in the mail that has a tiny bit too. I had assumed it may just be the linerless back locks, and to be fair that does count for 98% of what I handled today. Are my odds really crappy and I just got 20 or so knives on the lower end of tolerances?

And by vertical blade play, I don't mean the blade jiggles. You have to know what you're feeling for, but when you press/jiggle the blade up and down you feel a faint "click" kind of feeling. Maybe I'm just more in tuned with these sorts of things, I dunno. It's not a huge deal and won't at all effect performance, it's just an observation. I know wear on the FRN mold has a lot to do with it, because my original Native lightweight has developed a lot of lock rock, but these were all new knives.

[Blerv]

The vertical click is very common with lockbacks. I understand it to be the lockbar settling into the tang cutout. The linerless FRN seem to have a bit more flex and also lateral play due to a less anchored pivot.

It's tactile discomfort but in most cases completely safe (and very strong). You can usually minimize it by tightening the pivot but it makes the action quite stiff. It's part of the reason I prefer the other locks. The ambidexterity and affordable models (FRN) makes lockbacks tempting though.

[araneae]

My forum Native has some tiny degree of vertical movement. Sal has commented numerous times that this is perfectly normal. A lot of my mid locks have it, some do not. Doesn't bother me in the least, but if you are a touch OCD, I can see how it might bug you.

[Buendia518]

My forum Native has some tiny degree of vertical movement.

Maybe this is obvious but my regular black Native 5 takes very precise tinkering with the lockbar screw to get smooth opening and no vertical play.

[3rdGenRigger]

My linerless folders (Native and H1 Ladybug) have no play at all.

[Invective]

Pretty much all my backlocks had some small amount of up and down bladeplay. Off the top of my head, my Caly 3.5 SB, Jester G-10, ZDP Ladybug, SE Reverse S MeerKat (not technically a backlock but operates on the same principle), Endura4, and Benchmade Ascent all have maybe .5 mm of play, especially noticeable when pressing the blade down on a cutting board or other hard surface. I've grown used to it though, and as others have said, it is inherent in backlocks. It doesn't bother me as it is small and doesn't affect usage for me.

[Brock O Lee]

All 4 my lockbacks have some up-down play. That's why I try to avoid this specific lock if possible. I'm hoping for the best for the green Native.

[michaelm466]

This thread prompted me to check for play on my lock back, I only have three a Pacific Salt, Ladybug Salt and Buck 110. I tested for play several times with quite a bit of force from the very tip of the Pac Salt, closed and opened again and tried again, repeated 3-4 times, each time no play at all detectable, same with the Ladybug. Both are a bit stiff/tight in opening, but not overly so. I did detect a very small amount of play in the 110, kind of that click you talk about when I apply quite a bit of force on the very tip of the blade.

[yablanowitz]

Most of the time what you are feeling and hearing is the clearance between the pivot pins on the blade and lockbar and the holes in the blade and lockbar. There has to be some clearance or the parts won't move. When the blade is locked open, the spring pushes the blade down, taking up the slack in one direction. When you begin applying upward pressure on the blade (when you start to cut something), the first thing that will happen is you overcome the spring tension and move the pins against the other side of the holes. Depending on the amount of clearance between the pins and their holes, this movement may or may not be noticeable. I've noticed it on most of my lockbacks, even when the blade and lockbar are solidly mated and moving as one piece.

There is one sure way to avoid this. Don't buy folding knives. Stick to full tang fixed blades. Problem solved.

[nirvanero]

I only have a few linerless lockbacks and they show no blade play at all. My Spyderhawk didn't develop it even after being accidentally thrown to the floor (which left a little dent on the spine of the blade).

[The Deacon]

The vertical click is very common with lockbacks.

Exactly, and there's no correlation between it and price/construction. I've experienced it with riveted, pinned, and screwed together models, in lined and linerless FRN, G-10, Micarta, and CF, as well as in all metal and bolstered models.

[mrphotoman]

None of mine have any play.

[jackknifeh]

I'm no expert.

Try pushing the front of the lockbar down after opening the knife forcing it down into the groove in the tang. Then see if there is still play. If not the play may stop when the knife gets broken in. Locks are made these days that will "settle" into the locked position over time. The BBL for example. As the bearing goes in and out of the notch the notch may wear bigger but there is plenty of room for the bearing to go farther into the notch. Back locks are different of course but still this can be done I think but the precision needs to be perfect I believe. Just my thoughts and I won't swear by them.

[araneae]

I think the use of the word play, in reference to this slight movement is perhaps misleading. With a mid/back lock, this slight amount of lock bar movement is fine and not an indicator of poor quality or unsafe lock design. Yab explained it very well. Now, if you had a cheap-o linerlock from the gas station and you felt play when the lock was engaged, you would have right to be concerned, because that knife probably has a defective lock.

I still think this is more of an issue for OCD types. They are also likely to be the same people that think the blade must be perfectly centered or its a factory second.

[DougC-3]

All 4 my lockbacks have some up-down play. That's why I try to avoid this specific lock if possible. I'm hoping for the best for the green Native.

My Forum Native came last night. It has zero vertical (or other) play -- I can't force any. The fit and finish are perfect. Opening seems a tiny bit stiff, as expected with a new knife, but if you fully depress the lock, the blade swings totally free through the full arc, just like my Manix2's.

[Evil D]

I think the use of the word play, in reference to this slight movement is perhaps misleading. With a mid/back lock, this slight amount of lock bar movement is fine and not an indicator of poor quality or unsafe lock design. Yab explained it very well. Now, if you had a cheap-o linerlock from the gas station and you felt play when the lock was engaged, you would have right to be concerned, because that knife probably has a defective lock.

I still think this is more of an issue for OCD types. They are also likely to be the same people that think the blade must be perfectly centered or its a factory second.

Well it wasn't enough to stop me from buying it but I see nothing wrong with preferring that it wasn't there. If I buy a new car I expect the doors to shut tightly and not rattle even if they close safely. I expect the bumpers to line up with the fenders properly just as I prefer my blades to be centered. There's nothing wrong with wanting aesthetics to be on par with performance.

[Blerv]

Well it wasn't enough to stop me from buying it but I see nothing wrong with preferring that it wasn't there. If I buy a new car I expect the doors to shut tightly and not rattle even if they close safely. I expect the bumpers to line up with the fenders properly just as I prefer my blades to be centered. There's nothing wrong with wanting aesthetics to be on par with performance.

There is nothing wrong with preferences; we should all have them. I'm not sure if a semi-custom lockback in the neighborhood of $400+ would have close enough tolerances to avoid the vertical play.

The best thing one can do with production knives is decide if it will be a dealbreaker. If so, shopping other locks is the easiest route.

[amue]

If not the play may stop when the knife gets broken in. Locks are made these days that will "settle" into the locked position over time. The BBL for example. As the bearing goes in and out of the notch the notch may wear bigger but there is plenty of room for the bearing to go farther into the notch. Back locks are different of course but still this can be done I think but the precision needs to be perfect I believe. Just my thoughts and I won't swear by them.

Certainly not with backlocks. On all my backlock knives, the amount of movement has increased over time, not v.v..

[Zenith]

Some research on the Lockback / Backlock.

http://www.spyderco.com/forums/showthre ... t=lockback

http://www.spyderco.com/forums/showthre ... k-Question

I remember Sal saying something to the effect that in their testing at Spyderco the lockbacks with a slight amount of vertical movement did better than the ones that locked up solid with no movement. I don't recall him saying why. He just stated his observations. Apparently the ones that did give just a little bit were able to take more force before defeating and it happened enough to be noticed.

Personally I don't like any movement in my lockbacks at all but I have several that do move within what is deemed acceptable tolerances. I've come to accept movement in liner and frame locks but lockbacks like the Buck 110 spoiled me years ago. Even still I have many production and custom made lock backs since the lock back is my favorite lock and many of them do move just a tad from play somewhere in their make up but usually the lock bar moves with the blade. In other words the mating of the blade and lock bar is solid and the movement is from some other factor. Usually this is from the pivot pin or the lock bar pin or a combo of both not being as tight or as close in the tolerances as maybe they could be to match up to the hole drilled in the body/liners.

I see discrepencies many times with pivot pins I buy to make my own folders. Using a digital caliper you can see that although all in say a ten pack are 3/16" diameter with 1/4" heads that when you get down to it some are slightly larger and some slightly smaller than one another. There have been times after drilling the hole in the blade with a 3/16 drill that one 3/16 pivot pin would slide right in nice and easy and another from the same pack would not go in at all.

In FRN folders (fiberglass reinforced nylon) I've seen many from all makers using that material that the pivot hole becomes oval shaped or oblong over time and use which is enough to allow some movement. Usually the quick cure for this is to take out the pin from the factory and simply replace it with a new adjustable pivot in the next bigger size. In most cases the knives lock up solid again like when new.

I would imagine that even though G10 and Micarta are both a step up from FRN that given enough time and hard use the ones made without liners of steel or titanium would eventually succumb to the same forces as the FRN ones I've seen. I have yet to see evidence of it in my shop for a repair though.
STR

I underlined what I think is key and the "bladeplay" we tend to experience in a new knife.


Another quote by STR:

"Just my opinion but lateral blade play is not going to affect it much if its slight. Vertical, while bothersome is also probably of little concern regarding reliability but I agree its bothersome on some. Half a mm is my limit personally. Anything more than that and I don't much care for it.

There are some things that can be done to help reduce if not eliminate that vertical play though. I'd have to see it but it may be possible to take that play out by making some small adjustments. Little hard to explain but it depends on the type of movement you experience and each one is different.

If the movement is the whole lockbar lifting up then its probably more to do with the pin holding the lockbar in place. In those cases most of the time the hole in the bar is slightly larger than the diameter of the pin which allows it to move slightly. We are talking like a hairs width or less but in a folder that is all it takes.

There has to be some gap in these in production pieces. Otherwise it would slow the entire process down but also the pins are mass produced and some just don't have the same measurements as others. Many times when I've rebuilt a folder that had some movement it was eliminated after I redid the hole to a larger diameter and installed a new tighter fitting barrel. At other times, and again depending on the type of movement one has it has been the same as when it arrived to me.

In these situations you have either the above situation with the lockbar pin, or the same thing in the blade. This can be by itself in just one spot or it can be both. On ones I don't have to redrill holes on, well, they don't change usually. Other issuses like the folder handle can also be responsible. On some older FRN folders for example, especially some used hard in their lifetime, the holes in the FRN can become oblong or almost oval in shape vs round which can allow play. Many times its hard to determine what causes it until its all apart and then I can zero in on it.

Still in other lockbacks it can be a combination of all the above, and a slight gap where the lockbar and blade mate up. That is why eliminating one thing in the combo can still leave it with play. Its all a crap shoot until you can get down to the insides and really examine one. Hope that makes sense."

[The Deacon]

IMHO, it's not really fair to compare a back lock, especially a nail nick back lock like the Buck 110, with a midlock. The lock geometry is totally different and user expectations also differ. Can't recall ever hearing anyone claim a Spyderco midlock was too easy to open, but we hear a fair number of complaints that they're not "flickable" enough. How many here would buy a midlock Spyderco that had as much opening tension as a Buck 110, even knowing that increasing the blade tension considerably might eliminate that annoying little bit of vertical movement?