Recommendation? What does “Rock Solid lock up” actually mean?

[Buttersongguy]

Hi Guys,

I collect Spydercos and have a special love for PM2’s and GB1’s and 2’s. I have quite a few of these. Let’s take PM2’s for example - I’ve often seen the terms “Rock solid” and “fall shut” or “drop shut action” used to describe PM2’s but I’ve started to question what this actually means...

I must own over 20 PM2’s and grabbing the handle and moving the blade vertically while it is locked open have never seen vertical blade play which kind of makes sense to me due to the design of the sloped recess for the lock bar meaning the blade will always be stuck between the stop pin and the lock bar.

However the horizontal blade play is simply a function of how tight the pivot screws are...if it’s very loose then there is a lot of horizontal play. Try taking a screw out completely. If they are very tight then there is no horizontal blade play but the “action” may suffer. So if it’s one I’ve taken apart (a user) I tend to compromise by loosening the pivot screws just enough that the blade will just about start to drop with its own weight. It’s definitely not as “rock solid” (horizontally) when I adjust in that way compared to if I just tighten the pivot screws completely...so It seems like a bit of an oxymoron to me to be rock solid and drop shut or am I just rocking the blade sideways too hard in my tests lol?

 

[Boxer .45]

Rock solid is how all of my compression lock Spydercos felt. After some break in they basically fall shut with the slightest wrist motion. I don't like fall shut like a board falling to the ground on any of my knives. Its just not something I look for or prefer and I don't believe that was intended in design. Easy, yes, fall shut, not really.
I also hear people brag that they adjusted their knife to fall shut then whine about centering or side to side play.

 

[marcus52AR]

Means spine whacks are GTG

 

[Buttersongguy]

Rock solid is how all of my compression lock Spydercos felt. After some break in they basically fall shut with the slightest wrist motion. I don't like fall shut like a board falling to the ground on any of my knives. Its just not something I look for or prefer and I don't believe that was intended in design. Easy, yes, fall shut, not really.
I also hear people brag that they adjusted their knife to fall shut then whine about centering or side to side play.

Thanks, that makes perfect sense wrt my experience.

One thing I forgot to mention is I have one Caribbean leaf (so nothing to compare it to) but find the action on that cannot be even close to drop shut with no horizontal play - glad to hear anybody else’s experience with this knife. It is a compression lock but there is an extra groove in the blade which houses a metal pin in the handle so maybe some more friction?

 

[Knarls]

Thanks, that makes perfect sense wrt my experience.

One thing I forgot to mention is I have one Caribbean leaf (so nothing to compare it to) but find the action on that cannot be even close to drop shut with no horizontal play - glad to hear anybody else’s experience with this knife. It is a compression lock but there is an extra groove in the blade which houses a metal pin in the handle so maybe some more friction?

I have a Caribbean, I have been using it for about 5 months now.
It is well broken in, I can now get it to close with just a slight flick with absolutely no blade play side to side, very similar to a “newer” less broken in PM2 but not brand new if you know what I mean.

When I first got my Caribbean I thought it would never become that “free moving” which didn’t bother me. But I have been pleasantly surprised with the action as of late. One of my favourite knives of all time. Just wish it had a few more jimping notches similar to the pm2 or endura 4. Just my opinion.

Another thing to add is I have never taken it apart but I have loosened the pivot screw and dropped a few drops of nano oil into the pivot then tightened it back up to no blade play.

My pm2 on the other hand is about 3 years old and a very heavy user and it has absolutely no blade play side to side or up and down. And drops shut with just a push of the compression lock in the horizontal position.
It is a dlc coated blade if that makes any difference I don’t know.

I should also add that both knives have perfect blade centering.

 

[Buttersongguy]

I have a Caribbean, I have been using it for about 5 months now.
It is well broken in, I can now get it to close with just a slight flick with absolutely no blade play side to side, very similar to a “newer” less broken in PM2 but not brand new if you know why I mean.

When I first got my Caribbean I thought it would never become that “free moving” which didn’t bother me. But I have been pleasantly surprised with the action as of late. One of my favourite knives of all time. Just wish it had a few more jimping notches similar to the pm2 or endura 4. Just my opinion.

Another thing to add is I have never taken it apart but I have loosened the pivot screw and dropped a few drops of nano oil into the pivot then tightened it back up to no blade play.

My pm2 on the other hand is about 3 years old and a very heavy user and it has absolutely no blade play side to side or up and down. And drops shut with just a push of the compression lock in the horizontal position.
It is a dlc coated blade if that makes any difference I don’t know.

That’s really interesting, thank you. I have taken my Caribbean apart to oil it and check what was up with the action but haven’t really used it at all so it’s not broken in.

I have exactly the same experience on my DLC coated heavy user PM2 strangely enough. It was the first PM2 I ever got and it was drop shut with a little wrist action from new. It now falls shut like a guillotine, in a way that would make me think I had a lot of horizontal play (if it was any other of my PM2’s) but has little or no horizontal play. Definitely no horizontal play compared to if I loosened any of my other slight user PM2’s to have the same dropping action. I have never taken this one apart or taken a screw driver to any of the screws. Just Nano oiled the pivot best I could while it was together. I too was wondering if the dlc had something to do with this, or simply using it more than any of my others..I don’t believe taking it apart or not taking it apart makes any difference so long as it’s done carefully and the correct pivot tension is applied.

 

[Knarls]

That’s really interesting, thank you. I have taken my Caribbean apart to oil it and check what was up with the action but haven’t really used it at all so it’s not broken in.

I have exactly the same experience on my DLC coated heavy user PM2 strangely enough. It was the first PM2 I ever got and it was drop shut with a little wrist action from new. It now falls shut like a guillotine, in a way that would make me think I had a lot of horizontal play (if it was any other of my PM2’s) but has little or no horizontal play. Definitely no horizontal play compared to if I loosened any of my other slight user PM2’s to have the same dropping action. I have never taken this one apart or taken a screw driver to any of the screws. Just Nano oiled the pivot best I could while it was together. I too was wondering if the dlc had something to do with this, or simply using it more than any of my others..I don’t believe taking it apart or not taking it apart makes any difference so long as it’s done carefully and the correct pivot tension is applied.

Interesting, maybe the DLC.
I do believe it has a lot to do with use and “breaking it in”.
But perhaps the tolerances have changed over the years in production?
To make them less “free moving”

 

[Buttersongguy]

Interesting, maybe the DLC.
I do believe it has a lot to do with use and “breaking it in”.
But perhaps the tolerances have changed over the years in production?
To make them less “free moving”

It’s a really odd one. My engineering concept is pretty rudimentary but it’s not the most complicated set up either. My simple brain just thinks the harder you press the sides of the handle together at the pivot the less horizontal blade play and more drag there will be on the blade’s action. With my non user or tiny user PM2’s that I have or have not adjusted pivot tension on they are pretty predictable in terms of I can tell how much horizontal play to expect by the freeness of the dropping action. My first PM2 (Camo/dlc) which I have used a lot does not fit the same pattern. I wish I had tested it for horizontal play when it was new to see if it had a little that went away as the action became looser or started with none/very little and didn’t get worse as it got looser but if that’s the case I really don’t understand the physics of it. I even experimented on a new PM2 by polishing the washers to potentially mimic a break in period but it certainly didn’t change the action to match my dlc pm2.

 

[blades&wrenches]

To me "rock solid" means no play in any direction. Easier on some than others and usually a pretty narrow window to get that fall shut action with no side to side play. Especially on a new knife. A little tight at first usually leads to great action without play once broken in.

 

[Buttersongguy]

To me "rock solid" means no play in any direction. Easier on some than others and usually a pretty narrow window to get that fall shut action with no side to side play. Especially on a new knife. A little tight at first usually leads to great action without play once broken in.

That course of events would certainly tally with my experience on my main user pm2. Is there an accepted correct practice in terms of adjusting the pivot if it is not perfect from the factory? Ie tighten to the point it is slightly stiffer than one would like when full broken in, with no horizontal play..But..what about the correct method or in other words what they do at the factory? I tend to tighten the non show side then adjust the show side and back out the non show side and then finesse the show side. Is there a better way? I noticed in some Spyderco pivot designs the washer has to go in before the pivot which got me wondering if the washer is meant to rotate or is it meant to be stationary. I find the GB1 and GB2 can tolerate very loose pivot tension while staying play free but if I remember correctly they have the pivot design where the washer is trapped by the pivot.

 

[scottyj]

To me "rock solid" means no play in any direction. Easier on some than others and usually a pretty narrow window to get that fall shut action with no side to side play. Especially on a new knife. A little tight at first usually leads to great action without play once broken in.

Yup.

 

[Buttersongguy]

I think we are on the same page with regards what is meant by no horizontal play but it really depends on how much force you are able to put through the blade and where you hold the handle while you test it (ie not pressing the pivot together with one hand). I don’t think it’s physically possible to have absolutely no detectable horizontal play with a strong grip while the pivot is adjusted to allow the blade to move freely. Something has to flex and it’s going to be the only bit that isn’t fully done up (the pivot) before the handle starts to bend round.

 

[blades&wrenches]

That course of events would certainly tally with my experience on my main user pm2. Is there an accepted correct practice in terms of adjusting the pivot if it is not perfect from the factory? Ie tighten to the point it is slightly stiffer than one would like when full broken in, with no horizontal play..But..what about the correct method or in other words what they do at the factory? I tend to tighten the non show side then adjust the show side and back out the non show side and then finesse the show side. Is there a better way? I noticed in some Spyderco pivot designs the washer has to go in before the pivot which got me wondering if the washer is meant to rotate or is it meant to be stationary. I find the GB1 and GB2 can tolerate very loose pivot tension while staying play free but if I remember correctly they have the pivot design where the washer is trapped by the pivot.

I usually try show side screw first. Just out of habit. More often than not it will do the trick.

IMO, no washer should rotate with the blade. They should remain stationary. Not always the case, but ideally, they shouldn't move.

And yes, if you put enough force on it, you will probably be able to get some horizontal play. If no play is felt with a firm wiggle from side to side, that's good for me.

 

[Lapedog]

Hi Guys,

I collect Spydercos and have a special love for PM2’s and GB1’s and 2’s. I have quite a few of these. Let’s take PM2’s for example - I’ve often seen the terms “Rock solid” and “fall shut” or “drop shut action” used to describe PM2’s but I’ve started to question what this actually means...

I must own over 20 PM2’s and grabbing the handle and moving the blade vertically while it is locked open have never seen vertical blade play which kind of makes sense to me due to the design of the sloped recess for the lock bar meaning the blade will always be stuck between the stop pin and the lock bar.

However the horizontal blade play is simply a function of how tight the pivot screws are...if it’s very loose then there is a lot of horizontal play. Try taking a screw out completely. If they are very tight then there is no horizontal blade play but the “action” may suffer. So if it’s one I’ve taken apart (a user) I tend to compromise by loosening the pivot screws just enough that the blade will just about start to drop with its own weight. It’s definitely not as “rock solid” (horizontally) when I adjust in that way compared to if I just tighten the pivot screws completely...so It seems like a bit of an oxymoron to me to be rock solid and drop shut or am I just rocking the blade sideways too hard in my tests lol?

To me good lockup vs rock solid lockup means that even with quite abit of muscle you cannot wiggle the blade up and down even a tiny bit. Lots of knives that function just fine you can muscle a little flex up and down. It has nothing to do with side to side which is as you noted a factor of pivot tightness.

Also a rock solid lockup has no lockrock, no lock slip and when you pull the blade very hard into the stop pin the lockbar doesn’t move over any extra ammount. (A surprising number of seemingly quite solid locking knives can do this) Another thing is if I push hard on the lockbar I can’t push it any more towards the opposite scale.

However “rock solid” isn’t a technical term. That means there is no agreed on definition of what it actually means. In most use it seems to be just a marketing phrase.

 

[Buttersongguy]

I usually try show side screw first. Just out of habit. More often than not it will do the trick.

IMO, no washer should rotate with the blade. They should remain stationary. Not always the case, but ideally, they shouldn't move.

And yes, if you put enough force on it, you will probably be able to get some horizontal play. If no play is felt with a firm wiggle from side to side, that's good for me.

That’s good to know, thank you. All this time I took the washers for granted never really thinking about whether they were meant to turn or not. It’s amazing they last so long!

That’s exactly what I started to do - just a firm wiggle because when I went to test a bunch of knives with the words rock solid in my head I found I can move just about any folding knife side to side which was kind of stupid on my part because it’s not one solid piece of metal or rock and it needs to move to fold so of course it will move at a given pressure lol.

 

[Buttersongguy]

To me good lockup vs rock solid lockup means that even with quite abit of muscle you cannot wiggle the blade up and down even a tiny bit. Lots of knives that function just fine you can muscle a little flex up and down. It has nothing to do with side to side which is as you noted a factor of pivot tightness.

Also a rock solid lockup has no lockrock, no lock slip and when you pull the blade very hard into the stop pin the lockbar doesn’t move over any extra ammount. (A surprising number of seemingly quite solid locking knives can do this) Another thing is if I push hard on the lockbar I can’t push it any more towards the opposite scale.

However “rock solid” isn’t a technical term. That means there is no agreed on definition of what it actually means. In most use it seems to be just a marketing phrase.

Totally understand and agree. I am now seeing the light lol.

 

[Lapedog]

That’s good to know, thank you. All this time I took the washers for granted never really thinking about whether they were meant to turn or not. It’s amazing they last so long!

That’s exactly what I started to do - just a firm wiggle because when I went to test a bunch of knives with the words rock solid in my head I found I can move just about any folding knife side to side which was kind of stupid on my part because it’s not one solid piece of metal or rock and it needs to move to fold so of course it will move at a given pressure lol.

Most folding knives, particularly ones with teflon washers will allow a little bit of side to side movement if you really muscle it. This isn’t the same as bladeplay which is the result of looseness and slop in the pivot, but rather a little flex in the system.

Also “rock solid lockup” doesn’t technically describe side to side movement. Although if a knife too much side to side movement it will cause the lockface of the tang to wiggle against the lockbar and that in itself will negate a “rock solid” lockup.

 

[ric75]

For me its also important to be consistent.
I had a liner lock (not a Spydie) where the liner locked 10% or 50% dependent of the force i opened it.
It was also hard to disengage at 50% lockup.

If a Spydie locks it locks rock solid.
I can rely on a Compression lock 100% everytime anytime.

 

[Boxer .45]

If a Spydie locks it locks rock solid.
I can rely on a Compression lock 100% everytime anytime.

Why? Because you can't actually see the lock? Ive had multiple and I prefer and them over just about everything else. I trust them just fine.

 

[kniferbro]

I think you answered your own question. The dragon many of us chase is having smooth/free operation (drop shut) while at the same time being rock solid. This attribute is a function of tolerances, the tighter the tolerances the more "rock solid" it will feel while still having smooth/free operation.