Stretch 2 XL: torque wrench-like click under pressure

[barnaclesonaboat]

This is a question for the Stretch 2 XL folks:

Have you had any issues with a mild but distinct/sharp click when applying decent pressure to the blade?

I have a single example, a Micro Melt PD1 sprint. The action is generally great for a backlock, easy to deploy and close (although the pivot does have a tendency to loosen, and I routinely re-tighten it). The issue I am curious about comes up when I hold the knife in hammer or Fillipino grip, and apply pressure to the cutting edge in the most normal of ways… think cutting a piece of rope, or push-cutting to shave down a stick. As soon as pressure reaches a certain moderate level, there is an audible “click” like a torque wrench, accompanied by a fraction of a degree of blade movement in the opposite direction of the pressure/cut. The play/issue clearly has something to do with the backlock mechanism and the clicking sound and sensation come from that area of the knife. It really feels like a torque wrench!

Any clues? Adjustment tips to address the issue? I’d prefer not to send the knife in to Spyderco if this is a straightforward adjustment.

[marrenmiller]

I've encountered this on Enduras and Delicas. It's a result of poor lock fitment, as the lock bar acts as both a stop pin and a lock for the blade. This is one reason why I've largely stopped purchasing Seki Spydercos.

There's nothing you're going to be able to do about it other than keep using it and hoping it either breaks in and goes away or you stop caring about it. It is my understanding that Spyderco does not consider the lock fitment to be a warrantable item unless it actually slips under load.

[Guts]

Sounds like what's called "lock rock" in a backlock style knife. I have it on a few of my backlocks and it's a bit annoying (one happens to be the regular Stretch 2). I haven't looked into it enough to say exactly how it's caused but likely something with the lock geometry or perhaps the pivot. I'm sure others who are more knowledgeable about it will chime in.

[vivi]

This is a question for the Stretch 2 XL folks:

Have you had any issues with a mild but distinct/sharp click when applying decent pressure to the blade?

I have a single example, a Micro Melt PD1 sprint. The action is generally great for a backlock, easy to deploy and close (although the pivot does have a tendency to loosen, and I routinely re-tighten it). The issue I am curious about comes up when I hold the knife in hammer or Fillipino grip, and apply pressure to the cutting edge in the most normal of ways… think cutting a piece of rope, or push-cutting to shave down a stick. As soon as pressure reaches a certain moderate level, there is an audible “click” like a torque wrench, accompanied by a fraction of a degree of blade movement in the opposite direction of the pressure/cut. The play/issue clearly has something to do with the backlock mechanism and the clicking sound and sensation come from that area of the knife. It really feels like a torque wrench!

Any clues? Adjustment tips to address the issue? I’d prefer not to send the knife in to Spyderco if this is a straightforward adjustment.

That's how Spyderco designs their lockbacks.

They only make one model, as far as I'm aware, that has a lockback with no play. The chapparal, which has an internal stop pin.

Every Stretch and Stretch XL I've handled had this issue. So do the following models: Police, Delica, Pacific Salt, Tasman Salt, Catcherman, Endura, Ladybug, Dragonfly, C95 Manix & mini manix, native, native chief, etc.

[M_J87]

While I've had some small degree of lock rock in all of the Seki knives I've ever had, I figured it was worth sharing that I got a S2XL in K390 recently that had some pretty noticeable play and lock rock. To preface, I'm not typically one to look at things "under a microscope", but it was an apparent issue for me. I had adjusted the pivot and every other individual screw to no avail, but after complete disassembly it's been almost completely rid of these issues. I wiped all lube off, washed everything with dawn and water, dried off, reassembled/relubricated, and screwed to "my" spec: hand tight on body screws with the pivot just loose enough to fall while applying some inertia with the lock disengaged. Can't explain why anything short of complete disassembly and reassembly fixed it (my guess is a minute issue between the lock bar and blade interface when locked), but I'd advise trying it out.

[Bolster]

Faulty memory here, but wasn't there also a lockback Sage (Sage 4) with a stop pin? No longer in production of course.

[barnaclesonaboat]

I've encountered this on Enduras and Delicas. It's a result of poor lock fitment, as the lock bar acts as both a stop pin and a lock for the blade. This is one reason why I've largely stopped purchasing Seki Spydercos.

There's nothing you're going to be able to do about it other than keep using it and hoping it either breaks in and goes away or you stop caring about it. It is my understanding that Spyderco does not consider the lock fitment to be a warrantable item unless it actually slips under load.

Thanks for the notes - the knife does still feel very solid otherwise, so I'm encouraged based your suggestion of just living with it that I don't have a critical safety issue in my hands.

Sounds like what's called "lock rock" in a backlock style knife. I have it on a few of my backlocks and it's a bit annoying (one happens to be the regular Stretch 2). I haven't looked into it enough to say exactly how it's caused but likely something with the lock geometry or perhaps the pivot. I'm sure others who are more knowledgeable about it will chime in.

"lock rock" describes the motion/feeling of the click well, thanks for that. Now I know how to refer to the phenomenon in a way others may understand better...

That's how Spyderco designs their lockbacks.

They only make one model, as far as I'm aware, that has a lockback with no play. The chapparal, which has an internal stop pin.

Every Stretch and Stretch XL I've handled had this issue. So do the following models: Police, Delica, Pacific Salt, Tasman Salt, Catcherman, Endura, Ladybug, Dragonfly, C95 Manix & mini manix, native, native chief, etc.

This is good information to know - thanks @vivi I have two late-model Enduras that I've put through plenty of heavier tasks without noticing this click, but now I'm wondering if it was just the type of cuts I was typically making? Now that I'm aware, I'm going to dig out those two Enduras this evening to see what I can feel.

Regardless, I super appreciate the feedback from you all - knowing this is an existing design/tolerance issue helps me feel "fine" about just keeping and using the knife as-is without too much worry of lock failure. Thanks!

[R100]

This is a question for the Stretch 2 XL folks:

Have you had any issues with a mild but distinct/sharp click when applying decent pressure to the blade?

I have a single example, a Micro Melt PD1 sprint. The action is generally great for a backlock, easy to deploy and close (although the pivot does have a tendency to loosen, and I routinely re-tighten it). The issue I am curious about comes up when I hold the knife in hammer or Fillipino grip, and apply pressure to the cutting edge in the most normal of ways… think cutting a piece of rope, or push-cutting to shave down a stick. As soon as pressure reaches a certain moderate level, there is an audible “click” like a torque wrench, accompanied by a fraction of a degree of blade movement in the opposite direction of the pressure/cut. The play/issue clearly has something to do with the backlock mechanism and the clicking sound and sensation come from that area of the knife. It really feels like a torque wrench!

Any clues? Adjustment tips to address the issue? I’d prefer not to send the knife in to Spyderco if this is a straightforward adjustment.

I have this exact issue with my SE Stretch 2 XL Salt. I have a lot of Seki lockbacks and, as people have said, they all have varying degrees of lock rock.

The issue with the Stretch Salt is different. Mine only developed it after extended heavy use cutting through big grass tussocks. The other Seki lockbacks, including my Stretch 2 XL PE and VG10 which haven't seen such heavy use, just rock up and down but the SE Stretch Salt has the strong audible click you describe and a strange feel to it.

I have several Pacific Salts that have seen a lot more heavy use than the Stretch 2 XL Salt and they are just fine with my Pac Salt 1s the best and most solid. It makes me wonder if the Stretch XLs are right at the structural limit for the type of linerless construction they employ. I am a bit disappointed in the Stretch 2 XL Salts now and have gone back to the Pacific Salts for heavy use. I think the linerless XL is at it's best as a lighter duty knife with the FFG grind as per the VG10 and K390.

As always just my experience and my opinion.

Dan

[vivi]

It's not a seki city issue. It's a Spyderco issue.

I've owned 12 Native Chiefs. They all had lock rock. So has everyone I handled in shops (another ~30)

Every C95 and mini C95 I've handled had it (~12 or so)

Lockback Mini Manix 2 I handled had it.

I've handled or owned every generation of Native, starting with the OG. They all had it.

etc.

[ladybug93]

a stretch 2 xl with a triad lock would be a dream come true.

[vivi]

a stretch 2 xl with a triad lock would be a dream come true.

I'd love for this collab to happen but I doubt it ever will.

I like the zero blade play nature of triad locks, and how deep the lock bar engages the blade. very secure.

but I like everything else better on spydercos vs cs.

I just wish they'd change their lockback design to something with no play.

[R100]

It's not a seki city issue. It's a Spyderco issue.

I've owned 12 Native Chiefs. They all had lock rock. So has everyone I handled in shops (another ~30)

Every C95 and mini C95 I've handled had it (~12 or so)

Lockback Mini Manix 2 I handled had it.

I've handled or owned every generation of Native, starting with the OG. They all had it.

etc.

True. My Native Chiefs, Native 5s and Sirens all have some rock. Less than the Seki lockbacks though and the Native family are really pretty good.

Dan

[vivi]

Ah yeah, the Siren, both pre-cqi and post-cqi, suffer from this too.

I will agree Golden models tend to have less rock, but acting like it's a seki city exclusive issue doesn't match reality.

[barnaclesonaboat]

Checked out my Enduras after work, and there it is! I think that the click is just pronounced enough on my particular S2XL that I finally registered it, triggering the query. I feel like I understand these a bit better and appreciate the insight from you all. Great to learn the additional details that are leaking out here…

[R100]

Ah yeah, the Siren, both pre-cqi and post-cqi, suffer from this too.

I will agree Golden models tend to have less rock, but acting like it's a seki city exclusive issue doesn't match reality.

I agree. My S90V Siren is pretty good but my CQI Siren Salt has Seki level lock rock. Only the Chaparral is exempt from the problem. Due to the stop pin it is 100% solid and like many others here I wish this system was used more widely. It's odd that the stop pin is only used on one of the smallest lockbacks when it's the larger designs that would benefit most. I suppose it's because it must add complexity to the manufacturing process. Lock rock is not generally a big deal from a functional or safety perspective but it is annoying.

Dan

[JoviAl]

Ah yeah, the Siren, both pre-cqi and post-cqi, suffer from this too.

I will agree Golden models tend to have less rock, but acting like it's a seki city exclusive issue doesn't match reality.

I agree. My S90V Siren is pretty good but my CQI Siren Salt has Seki level lock rock. Only the Chaparral is exempt from the problem. Due to the stop pin it is 100% solid and like many others here I wish this system was used more widely. It's odd that the stop pin is only used on one of the smallest lockbacks when it's the larger designs that would benefit most. I suppose it's because it must add complexity to the manufacturing process. Lock rock is not generally a big deal from a functional or safety perspective but it is annoying.

Dan

I completely agree. I’ve found my larger back lock knives regardless of manufacturing location to all have or develop lock rock. It doesn’t make me want to get rid of them, but it also doesn’t make me want to buy another one if I’m being completely honest Even my Chap SE LW is starting to develop a tiny bit and I practically only cut fruit and the odd bit of packaging very gently with that one

[vivi]

Yeah, it's not enough to keep me from buying Spyderco lockbacks, that's for sure, but I'm going to keep bringing this up until I can buy a Spyderco lockback with no play. Squeaky wheel and all.

[Red Leader]

I grew up on an Endura, and still have it, and it has lock rock which has gotten worse over time. I've generally moved on from back locks, but like others, this would also be a reason to keep me from going back to them.

Generally speaking, are there examples of knives that use a back lock or mid-back lock that do not really develop lock rock? How is everyone's old Buck 110 doing?

I also have a CS SR1 Lite, and if I don't manually seat the triad lock down all the way, I have the tiniest amount of play. Doesn't bother me really, and I do wish Spyderco would be able to have a successful collaboration with Demko on the Triad and Shark locks. As a lefty, I appreciate when knife companies consider non-hand dominant specific attributes in major elements of their design, though I have found a good way to unlock the compression lock in a way that allows me to carry one as my main user (lefty).

[Jesla]

My 30+ year old buck 503 has zero “lock rock”…. It is well used and was edc’d for over 20yrs, until it became too much of a risk for loss. Carried it so much the wood scales are coke bottles shaped from wear.