Question On Vert.bladeplay Developing.

[MANIXWORLD]

I dont want to drag this one out,but with our lockback Spydies that come to us with zero vertical bladeplay,'how does vertical bladeplay develop over time?does the lockbar and other metalparts start wearing down, from contact and friction,which could lead to the above mentioned?does anyone have lockback Spydies,that has developed vert.bladeplay over use and time?

[mr_bsii]

I have a delica wave (still my main user/edc) that has tread the path of which you speak. No play at all when first acquired, although mine didn't develop vertical play gradually. It occurred when cutting some of the very large (~3/8 or 1/2") zip ties. I'm not sure exactly what got wallowed, flattened, damaged etc., but it now has a little vertical blade play. I've had it apart to see if I could see a flat on the pivot or noticeable damage to one of the liners, but nothing was visible to my admittedly un-calibrated, naked eye. If I could tell which part it was and had confidence that a rebuild kit would take care of it, I'd probably order one (I may order one any way just to give it a shot). Regardless, I'm lookin forward to hearing from the Dudes That Know... and the Dudettes That Know...

bs

[JBE]

A slight amount of vertical blade play is not uncommon in back lock folders as long as it's not excessive.

[Franco G]

A slight amount of vertical blade play is not uncommon in back lock folders as long as it's not excessive.

True. But it is still a sign of poor quality.

[MANIXWORLD]

A slight amount of vertical blade play is not uncommon in back lock folders as long as it's not excessive.

im actualy just interested in knowing how vert.bladeplay develops over time.
I feel that the lockback locks are some of the best locking mechanisms,but everything nice,has its drawbacks.

[JBE]

I believe it may have something to do with wear at the point where the blade meets the lockbar. Also, the spring will lose a slight amount of tension over time. Two metal surfaces in constant contact with each other will wear with time and use..it's inevitable.

Every lock has its advantages and disadvantages.

Maybe one of our resident modders (STR, Tricod, et. al.) can add a bit more insight as to why this happens and develops.

As far as being poor quality...I doubt it. I have yet to see a lockback - regardless of manufacturer - that this doesn't affect unless it's sitting in a drawer unused. If there is such a beast, please enlighten me on where to find one.

[STR]

True. But it is still a sign of poor quality.

This is not true at all. Many of the higher dollar customs will exhibit a slight amount of blade play. In many testings lockbacks with a slight amount of play have actually outperformed ones with none for strength and breaking point. Why? Not sure. We suspect some reasons but its speculation at this point, at least in my own mind.

What you will see looking at lockbacks is that once the folders are assembled to test fit by either the maker or the manufacturer many times some final 'tuning' is done by the cutler or cutlers as the case may be. You may note on some that have little hash marks for lack of a better description, and these marks will be on either side of the lock bar looking straight in from the very front of the folder by the pivot.

These hash marks as I call them are marks made that much like the trick used by cutlers to take vertical play out of a liner lock physically 'squishes' metal out just a half a hairs width futher at the contact so that portion of the lockbar or liner lock comes into contact with the blade sooner and tightens up the lock up.

What usually occurs is that these 'hash marks' simply wear down with use and you 'redevelop' blade play again but its usually not as bad as it was before this tuning was done.

If you want to talk about quality lets talk about that but this has nothing to do with it. When a maker or manufacturer takes time to fine tune the folders they make, inspect them, test them and back them up they are making quality products. When they hap hazardly slap them together and make no effort at all to do all or even some of these things then we can talk about the true definition of the term. Believe me there are some out there that are not quality. Spyderco is not one of them. End rant.

STR

[STR]

I believe it may have something to do with wear at the point where the blade meets the lockbar. Also, the spring will lose a slight amount of tension over time. Two metal surfaces in constant contact with each other will wear with time and use..it's inevitable.

Every lock has its advantages and disadvantages.

Maybe one of our resident modders (STR, Tricod, et. al.) can add a bit more insight as to why this happens and develops.

As far as being poor quality...I doubt it. I have yet to see a lockback - regardless of manufacturer - that this doesn't affect unless it's sitting in a drawer unused. If there is such a beast, please enlighten me on where to find one.

You hit it pretty much on the head. Its about wear.

As for the OP question. Even on the folders regardless of the lock type that did not need fine tuning because the maker or manufacturer hit everything perfectly dead on and within tolerance the first time you have wear that will develop. For example, all those nice crisp corners get rounded and when you take a knife made for hard use people tend to be hard on it.

If you want to see typical examples of this type corner and edge rounding its easy. Simply buy you a nice Manix or another finer take apart type model with a screw construction and examine it before doing anything. Then take some scans, some detailed digitals or just make mental note of the condition if you want. Put it all back together and spine whack it off and on for the time you own it making yourself feel better about how good your lock is by repeated and uncessary testing. It will round off right quick and develop play for ya at an accelerated rate trust me. I've even seen them with metal sheared off in places you could not see when it was all put together.

STR

[Franco G]

Steve, I am sorry for my very strong claim. I do not want to badmouth Spyderco at all, but to express the fact that a slight blade play, although not compromising the excellent reliability of Spyderco knives, is still very annoying. Sorry for strong expressions, my apologies to Sal, English is not my native language.
However, I based my claim on one of your explanations where you explained why it comes to a small blade play (something with a tuning of pivot? - I cannot find this particular thread, I'll try it).

In my opinion, I see no reason in physics why it should exist a blade play. It is only a question of tolerances.
Including a tolerance by ELUs.

Franco

P. S. In my opinion 'rant' is very strong expression too. A rant or harangue is a speech or text that does not present a well-researched and calm argument; rather, it is typically an attack on an idea, a person or an institution, and very often lacks proven claims. Such attacks are usually personal attacks. (Wiki)

[zenheretic]

P. S. In my opinion 'rant' is very strong expression too. A rant or harangue is a speech or text that does not present a well-researched and calm argument; rather, it is typically an attack on an idea, a person or an institution, and very often lacks proven claims. Such attacks are usually personal attacks. (Wiki)

Sometimes the book definition doesn't match the useage, at least in English. :)

For example, although STR said he was ranting, his argument was reasoned, polite, and just talked about mechanics. By rant, he meant more that he had a strong opinion on the matter, not that his disagreement had no basis in truth. Had his words been a book definition of a rant, he would have attacked you as a person, where you are from, the sort of thing that nothing to do with the locks. :)

[STR]

No personal attack intended and my apologies for not giving the benefit of the doubt on an international forum that some users may not speak English as their primary lanquage. You would think by now I would have learned this. I simply answer this same question a lot so it seems like I'm ranting more to myself than anyone in particular.

The quality of the folder is fine in these cases. Its the quality control of those responsible for examining them before they get out the door on their way to end line users that are the culprits if one gets out that isn't ready yet or that was faulty. It happens no matter how good you are though.

Still I hate getting into nit picky arguements over definitions and sometimes I spit stuff out real fast that I should probably word better. My bad if this is one of those cases.

All of us use what we term 'raw materials' and although we use these raw materials, IE, pins, screws, barrels, sheet metals and more we do not make them or manufacture them (usually). By definition Spyderco, like many of the quality cutlery manufacturers and makers in the industry, uses quality raw materials. For example Spyderco's G10 has a higher glass fill than that usually sold at suppliers. With that said though keep in mind that many times, even with quality raw materials, quality control drops the ball there at times and you get one that fell in the batch that is by all definitions out of tolerance. Wear contributes to a larger part than this in blade play issues but its also about the way many makers and I'm sure manufacturers do things.

For example, if I want to install a 3/32 pin I would drill that hole for the pin usually with a # 41 drill or a number 42 if I can find one. These are slightly oversized by about the thickness of a thin piece of paper. You have an exact measure of .0938 with a 3/32 pin and a .0960 size hole using a number 41 drill bit. With a 1/8" pin you would have a .125 pin size with a . 1285 drill bit in the way of a number 30 drill and so on and so forth.

The tolerance is there even in these oversized drills, but there is room for play if say the pin I use is smaller than it should be and lets suppose its off by another sheet of paper or more. It happens. Usually its not much more than the width of a hair if that but as we all know that can be huge in a folding knife and you will see that in things like play so the 'fine tuning' I mentioned above comes into play to make up for any lackings in the raw materials. Does that mean the knife is sub par in quality? Well, if you want to nit pick perhaps we could go back and forth about that but truthfully the folder is still a quality made product and these slight bits of play will not in any way affect performance overall. If you look at many of the pinned folders both made today and from yesteryear that have served their owners quite well you can see even in the brand spankin' new ones that they all had not only side to side blade play but also a small amount of vertical.

I've said this before and I'll type it one more time. In my experience you are hard pressed to see wear in a lockback like you do in other lock types. Its a tried and true design that has proven itself over many years. This quote of course predates the invention of ball locks, axis locks and arc locks which you have to struggle even more to see developed play in since they self adjust for wear to an extent but I'm sure you follow what I'm saying. If not I'm simply stating that overall if a lockback comes from the factory with a little play and I note it in an eval when new I am hard pressed to see a difference in play even 35 years later after many many years of use such as I can testify to in one of the first lockbacks I ever bought for myself in that Buck 112 I've had since 1972. It has had a slight play vertically since I brought it home from the Davidson Army & Navy Surplus Store in my home town in Keyser WV back then. I almost returned it but it worked so well and was so much sharper than the only other choice I had at the time that to me it was worth keeping. I'm glad now that I did. Its been a good friend and hard user all these years.

Again, no offense or attack was directed at anyone here. I'm just throwing out there what I see. You have every freedom to dispute or disagree with it. That is how we learn and grow.

[Wharnie]

OK, I read STR's response, it's well thought out, backed up by evidence, and enlightening as always.

But I still agree with Franco's original post. I don't expect or tolerate blade play in new quality knives.

You have to admit that, to some extent, quality is in the eye of the beholder. There may be a dozen good reasons a knife has blade play, but I am looking for one that doesn't. To me, blade play even from a top quality manufacturer screams "low quality" or "monday morning knife" if new or "worn out" if used.

That's one reason I buy Spyderco. Most all of my Spydercos lock up tight and solid.

I have owned some blades with a moderate amount of vertical play and it drives me crazy, I hate it. It may be safe but it sure doesn't feel like it. And I'll bet dollars to doughnuts, that given two knives comparable in all other ways, the one that locks up tight is a safer knife than the one that slops around.

That said, I think the future of knife locks will self-adjust for wear. Doesn't the ball lock do that to some extent? [Edit:] Aha, just reread STR's last response and he says as much.

[STR]

OK, I read STR's response, it's well thought out, backed up by evidence, and enlightening as always.

But I still agree with Franco's original post. I don't expect or tolerate blade play in new quality knives.

You have to admit that, to some extent, quality is in the eye of the beholder. There may be a dozen good reasons a knife has blade play, but I am looking for one that doesn't. To me, blade play even from a top quality manufacturer screams "low quality" or "monday morning knife" if new or "worn out" if used.

That's one reason I buy Spyderco. Most all of my Spydercos lock up tight and solid.

I have owned some blades with a moderate amount of vertical play and it drives me crazy, I hate it. It may be safe but it sure doesn't feel like it. And I'll bet dollars to doughnuts, that given two knives comparable in all other ways, the one that locks up tight is a safer knife than the one that slops around.

That said, I think the future of knife locks will self-adjust for wear. Doesn't the ball lock do that to some extent? [Edit:] Aha, just reread STR's last response and he says as much.

Well, no one was talking about 'slopping around' here to my knowledge. I thought we were discussing slight blade play in lockbacks. Sloppy play is an entirely different story altogether. It sounds like some of you draw the line for out of tolerance in a different place than I do. For me if blade play is beyond slight, and by slight I mean enough to see a space between the lock bar and the folder blade then it starts to get into the 'sloppy' area for play. I would venture to say that in this case Sal would be the first to agree with you and that it should be fixed or replaced if its slopply play.

I mentioned the type blade play from contact due to wear, but lets discuss more on the type play where the lock bar and blade contact is solid and in fact is not an issue but in fact one of the pins or holes drilled is too large for the pin and it allows the lockbar to lift up when you push down on the blade in a cut. Many times simply swapping the pins can alleviate play or improve it enough to satisfy an end line user. This has worked for me and when it has worked a little it made it good enough to keep it long enough to wait on a replacement pin to arrive from a supplier or manufacturer.

To the OP. Have you tried this? Take the pin out of the pivot and put it in the lockbar and the lockbar pin in the pivot of the blade. See what happens. I quit trying to figure out what occurs here or in other weird situations. I just know its worked at times and although it worked it still leaves me scratching my head a bit.

STR

[yablanowitz]

I also think that people fail to take into account the number of places in a lockback which combine to create "play".

1) There has to be some clearance between the pivot and the pivot hole in the blade, or the blade won't fold. A lot of clearance is not good, but some is vital.

2) With adjustable pivots (screw construction) there will be some clearance between the pivot screw and the liners. If there isn't, assembly becomes a major undertaking where the pivot has to be pressed in, and disassembly is nearly impossible without damaging something. Pinned construction avoids this by swelling the ends of the pins to eliminate the clearance, but they are not intended to be disassembled and reassembled.

3) & 4) The same things apply to the lockbar pivot as well as the blade pivot.

5) After all that, then we get to the actual mating surfaces of the blade and lockbar. There has to be a small amount of clearance here or the lock wedges into the lockwell on the blade and sticks. Not too much, but you need to start with some. The problem is, these are the hammer and anvil that get pounded together every time you wave, flick, or full-bore Spydiedrop open your knife. Not only that, but guess what that hammering does to the lockbar pivot. Yep, it peens that part, too.

So, if you start on a new knife with one thousandth of an inch of clearance between the blade and pivot, one thousandth between the pivot and liner, one thousandth between the lockbar and its pivot, one thousandth between the lockbar pivot and liner, and one thousandth between the lockbar tab and blade lockwell, you now have a total of five thousandths of an inch of "play". Since the length of the blade from pivot to tip is fifteen times as long as the distance from the pivot to the lockface, that will show as 75 thousandths of an inch at the blade tip. (That is an approximation based on my memory of measurements I made on pictures of a Pacific Salt several months ago.)

Is one thousandth of an inch of clearance in each place reasonable to expect on a production knife? Considering STR is talking about two to three thousandths between pin and hole size if everything goes according to plan, I kind of doubt it. Realistically, two thousandths of an inch is about all I would expect on a good production folder. Multiplied by the five points I mentioned and magnified by the blade length, it comes up to over an eighth of an inch at the tip, which most people would consider excessive.

Frankly, it amazes me that these lockbacks have as little vertical play as they do.

Edit to add: I just checked a few, and the hairs on my arm average two-and-a-half thousandths of an inch thick, just to give a sense of scale to all this.

[STR]

Keep in mind that much of my experience is 'old school' and that I cannot speak of the tolerances or lack of tolerances in a modern waterjet laser cutter. Nor can I really speak of how many more modern makers using more modern CNC equipment work. I do know this though. Many if not all the holes in a lot of modern production pieces are drilled with laser cutters and not drills. In an assembly line of products being made it has to run smoothly. If the factory is using 5/32 pins in the Manix and Mini Manix pivot and lockbar and drilled the holes exactly 5/32 in size it would slow down production by dropped parts all over the place, pins getting stuck part way down and stuff like this. This, in a day and age when time is money is not acceptable. We can't have that and survive in a business. There are always some areas where compromises have to be made because fine tuning can make up for most of that in the final tweaks.

If the employees are wearing blisters on their fingers and thumbs trying to assemble the things from exact precisely fitting parts its a bad day for workmans comp. claims. :D Truthfully, I am sure much of what is done is machine done these days but to be honest I don't much know how they do things these days with the CNC modern day machining. Its been a long time since this gent has toured a knife factory. I understand things have changed quite a bit.

I only know what I see and measure on my end. Many times in my shop when I've rebuilt a folder sent to me with blade play I've alleviated that play entirely when I changed the pivot and lockbar hole sizes for the new body. At other times it still exhibited just as much play as before and other times slightly less and dare I say, slightly more. I try real hard in my practice to make them fit as tight as possible for those using me and I have been known to start over rather than try to make something so far out work when its beyond hope. We all do that.

Again though on quality and the eye of the beholder. Lets compare cars for arguements sake. Lets take my wife's Jeep Liberty. Its a nice qualtiy car we ordered and bought brand new. My wife loves it. It had a faulty tranny when new and one window roller was bad and we had to have a new one put in for both parts. Now its A1. One bad part or even two does not, in my book, make for a bad quality product really. It makes for a bad quality part in a quality product that can easily be covered and fixed but thats just me.

As I've mentioned before we are all in the practice of making quality built products for the end line users. Of course there is an ideal to shoot for and we hope to do that. Some come closer than others. Some don't and fall way short but still meet tolerance expectations. Its the same in dentistry. That is why when a dentist does what he or she went to school for we call their business a dental practice when we refer to them.

The best dentist in the world can make a bad filling. His dentistry as a whole is quality dentistry though. So when I read this is bad quality and then see it referring to a product I see as very much a quality product I want to draw these distinctions in their defense because one bad apple here should not sour the whole barrel. Not that anyone was suggesting that but we have many that lurk here just reading. We need to be clear on our definitions for their sake as well as others that do post. The whole reason I even comment is because I don't want some folks getting the wrong impression or worse, running off saying next time they see a Spyderco that, "oh I won't own one, I read that those are not quality and have blade play."

STR

[A.P.F.]

I would like to 'stickey' your last post, STR, well written.

[MANIXWORLD]

OK, I read STR's response, it's well thought out, backed up by evidence, and enlightening as always.

But I still agree with Franco's original post. I don't expect or tolerate blade play in new quality knives.

You have to admit that, to some extent, quality is in the eye of the beholder. There may be a dozen good reasons a knife has blade play, but I am looking for one that doesn't. To me, blade play even from a top quality manufacturer screams "low quality" or "monday morning knife" if new or "worn out" if used.

That's one reason I buy Spyderco. Most all of my Spydercos lock up tight and solid.

I have owned some blades with a moderate amount of vertical play and it drives me crazy, I hate it. It may be safe but it sure doesn't feel like it. And I'll bet dollars to doughnuts, that given two knives comparable in all other ways, the one that locks up tight is a safer knife than the one that slops around.

That said, I think the future of knife locks will self-adjust for wear. Doesn't the ball lock do that to some extent? [Edit:] Aha, just reread STR's last response and he says as much.

Bro,i like the term you use'Monday morning knife'.
maybe the person who was operating the machinery in the manufacturing and assembling line of knives,was daydreaming or hungover at the very moment and the result was a knife with bladeplay.
fact is,if one knife has it/bladeplay and another NOT in the exact same model,its plain unacceptable.
its like having a case of a semi dislocated shoulder,that clicks back into place soon as you move your arm in a certain direction,but it still sort of operates like a healthy shoulder.LOL.

[bladese97]

:spyder: :spyder: :cool: :spyder: :spyder: This is just my opinion, but I think it has to do with "hard use", and plain old wear :D Please correct if incorrect :)

[Water Bug]

Those are some well-written posts, STR. I have a Buck 110 that I bought new back in 1979. It has some side-to-side play, and yeah, the blade play bothered me for a while, yet I've remained faithful to the knife and it to me. My Buck 110 has served me very well over the years, it serves me well today, and it still has a place of honor on my belt. Today it works in conjunction with my :spyder: s. I've found some blade play in a couple of the :spyder: s that I own and have accepted it as I have with my Buck. By the way, even today my Buck 110 often gets drawn first when the need arises. :) Thank you for the information and for sharing your experience!