I don't understand why Spyderco pivots self loosen

[Zipper]

There's a video out there somewhere of a Spyderco employee assembling knives using a torque driver.
[/quote]
I believe it! I'd be interested to learn the torque numbers that they're using.
[/quote]

I wouldn’t be surprised if it is just the recommended for the size of the Torx screws.
https://www.wihatools.com/pages/torx-sizes

[RustyIron]

This makes me wonder if a torque wrench might be useful to help actually quantify knife pivot tightness.

It would not be useful in this particular instance. If you tighten the screw, the blade becomes tight and the knife unusable. That's why we leave the pivot screws loose and why Vivi is having a problem.

knowing the most appropriate torque settings for the screws on our own respective knives during assembly might prove beneficial.

Yes! But keep in mind that knife companies don't get to "invent" the appropriate torque values for their fasteners. They use tables and equations just like the manufacturers of every other product you can imagine. Rolex watches, espresso machines, diesel locomotives--they're all built according to the math. The final torque values are dependent on the fastener size, thread pitch, and materials involved.

In the old days I would have to roll my chair over to the bookcase. Nowadays, without moving my chair, I google on "thread torque table" and get served up dozens of tables. It doesn't have to be rocket science... but it can be. This NASA document came up in one of my searches. It contains the torque values you seek.

https://ntrs.nasa.gov/api/citations/201 ... 003491.pdf

[holokai]

One thing I didn’t see brought up in the discussion on torque spec was surface prep/cleanliness. Any sort of anti-seize or thread locker will serve as lubrication and lead to over-torquing if not accounted for.

Additionally, inconsistent application of thread locker and relatively low torque values required to tune the knife action, along with tolerance stacking in parts, washer surface finish/friction, etc. work against using torque wrenches as a means to consistently dial in a knife’s action.

I like the idea of using a torque wrench as a torque limiting device to ensure the threads don’t get stripped (especially those terrible little T6s).

That said I try to get the surface as clean as possible before reassembly by making sure all threads get solvent and wiped/air dried to remove any contaminants. Body screws get snugged up to where I feel the underside of the screw head just starting to bite/grab the scale material, pivot screws get reassembled with thread locker, the action get tuned, and the knife gets left alone for a couple of days to let the thread locker set up.

[Palestrina]

I noticed this on my Brown FRN Delica recently. I noticed it dropped shut very easily when I depressed the lock compared to my newer Superblue Delica. There was also some *slight* side to side play. Tightened up the pivot & all is good. Could not even begin to tell you when the last time was that I tightened it.

This is my experience as well, out of my 8 Delicas I had to tighten the screw on only one (my EDC since a few months) until now, and I never had to do it again. The Delica platform does not seem to be affected by this issue that much, whereas it is a constant struggle on my Urban.

What's even more irking is that many times they fail to apply loctite correctly at the factory, and this is especially true of Seki City. Golden models are usually better.

I've just accepted the fact that with every new knife, I'm going to have to remove at least the pivot screw and sometimes the stop pin / lock bar screw, apply loctite, and let it dry before the knife is ready to use.

In the grand scheme, it's a minor inconvenience I'm willing to tolerate.

You do this on every model automatically? As stated above I've only had this issue on one Delica, and just tightning it up a bit seemed to have solved the issue for me.

[ejames13]

I noticed this on my Brown FRN Delica recently. I noticed it dropped shut very easily when I depressed the lock compared to my newer Superblue Delica. There was also some *slight* side to side play. Tightened up the pivot & all is good. Could not even begin to tell you when the last time was that I tightened it.

This is my experience as well, out of my 8 Delicas I had to tighten the screw on only one (my EDC since a few months) until now, and I never had to do it again. The Delica platform does not seem to be affected by this issue that much, whereas it is a constant struggle on my Urban.

What's even more irking is that many times they fail to apply loctite correctly at the factory, and this is especially true of Seki City. Golden models are usually better.

I've just accepted the fact that with every new knife, I'm going to have to remove at least the pivot screw and sometimes the stop pin / lock bar screw, apply loctite, and let it dry before the knife is ready to use.

In the grand scheme, it's a minor inconvenience I'm willing to tolerate.

You do this on every model automatically? As stated above I've only had this issue on one Delica, and just tightning it up a bit seemed to have solved the issue for me.

I check whether they’re secured by lightly attempting to turn the screws with a torx driver. If they budge, I removed them and apply my own loctite.

[zhyla]

That's why I question if actually knowing the particular torque spec of your desired "blade movement" would help to be able to repeat that action during future maintenance. If judging by feel alone is sufficient enough for our personal needs, that's fine, it clearly works but I also don't see a disadvantage to the capability of quantifying it.

The way tolerances stack I think that torque value for the same “tightness” between two knives is going to make a spec useless. It’s like telling someone how hard to push the brakes to stop a car at a stop sign.

Plus I’m pretty sure the difference between too tight and just right is like 1/10th of a foot-lb. It just has to be dialed in my hand.

[SpeedHoles]

Additionally, inconsistent application of thread locker and relatively low torque values required to tune the knife action, along with tolerance stacking in parts, washer surface finish/friction, etc. work against using torque wrenches as a means to consistently dial in a knife’s action.

This.
Also on top, the quality and calibration of consumer grade torque wrench/drivers in the low in/lb (talking like decimals of a nM) ranges mean these real world results and feedback would be ALL over the place, even if we were provided a "factory knife spec".

[Mushroom]

This makes me wonder if a torque wrench might be useful to help actually quantify knife pivot tightness.

It would not be useful in this particular instance. If you tighten the screw, the blade becomes tight and the knife unusable. That's why we leave the pivot screws loose and why Vivi is having a problem.

In regards to the pivot screw, we obviously shouldn't be tightening the pivot screw down to the point where there is concern for failure. I was suggesting a torque wrench be used more so as a gauge to help find the desired sweet spot for the pivot. That "sweet spot" has a value of its own and I was thinking a torque wrench might be a helpful tool to quantify that and make it repeatable during maintenance.

knowing the most appropriate torque settings for the screws on our own respective knives during assembly might prove beneficial.

Yes! But keep in mind that knife companies don't get to "invent" the appropriate torque values for their fasteners. They use tables and equations just like the manufacturers of every other product you can imagine. Rolex watches, espresso machines, diesel locomotives--they're all built according to the math. The final torque values are dependent on the fastener size, thread pitch, and materials involved.

In the old days I would have to roll my chair over to the bookcase. Nowadays, without moving my chair, I google on "thread torque table" and get served up dozens of tables. It doesn't have to be rocket science... but it can be. This NASA document came up in one of my searches. It contains the torque values you seek.

https://ntrs.nasa.gov/api/citations/201 ... 003491.pdf

I do appreciate the link. I think those values could be useful reference for avoiding failure of body screws and clip screws on knives. The pivot, as noted, would likely not apply.

I understand that fasteners themselves have varying torque specs to avoid failure and those values are used by manufacturers during their assembly process but I still think it could benefit the end line user to also be aware of those values if they're doing their own maintenance.

That publication from NASA notes that those table were created to have something more reliable and repeatable than feel alone. That was kind of my idea for using a torque wrench with the pivot.

"... Usually, the indications when tightening under these conditions are just “hand tight” or “wrench tight” or “snug." However, these are not accurate designations since they have so many variants between person, location,
etc. A defined reference chart for torqueing to a proper value is necessary to have consistency and prevent
failures." - Page 1: Introduction

Maybe a torque wrench is just overkill and overcomplicating something like a knife pivot. Like using a sledgehammer to crack a peanut. Going by feel obviously works for so many of us; it works for the pivot screw and everything else really.

That's why I question if actually knowing the particular torque spec of your desired "blade movement" would help to be able to repeat that action during future maintenance. If judging by feel alone is sufficient enough for our personal needs, that's fine, it clearly works but I also don't see a disadvantage to the capability of quantifying it.

The way tolerances stack I think that torque value for the same “tightness” between two knives is going to make a spec useless. It’s like telling someone how hard to push the brakes to stop a car at a stop sign.

Plus I’m pretty sure the difference between too tight and just right is like 1/10th of a foot-lb. It just has to be dialed in my hand.

Right and that's totally fair. The results of using a torque wrench for the pivot would be relatively unique to each individual knife and likely not result in a value that can be shared between others.

There are torque wrenches capable of making very fine scale measurements though. If we were to dial in our own knives using a fine scale digital torque wrench, it would at least provide us with a baseline to aim for the next time we did maintenance. Again though, I understand how this might be overcomplicating the whole process when it's ultimately going to come down to feel anyway.

[SpeedHoles]

This makes me wonder if a torque wrench might be useful to help actually quantify knife pivot tightness.

It would not be useful in this particular instance. If you tighten the screw, the blade becomes tight and the knife unusable. That's why we leave the pivot screws loose and why Vivi is having a problem.

In regards to the pivot screw, we obviously shouldn't be tightening the pivot screw down to the point where there is concern for failure. I was suggesting a torque wrench be used more so as a gauge to help find the desired sweet spot for the pivot. That "sweet spot" has a value of its own and I was thinking a torque wrench might be a helpful tool to quantify that and make it repeatable during maintenance.

knowing the most appropriate torque settings for the screws on our own respective knives during assembly might prove beneficial.

Yes! But keep in mind that knife companies don't get to "invent" the appropriate torque values for their fasteners. They use tables and equations just like the manufacturers of every other product you can imagine. Rolex watches, espresso machines, diesel locomotives--they're all built according to the math. The final torque values are dependent on the fastener size, thread pitch, and materials involved.

In the old days I would have to roll my chair over to the bookcase. Nowadays, without moving my chair, I google on "thread torque table" and get served up dozens of tables. It doesn't have to be rocket science... but it can be. This NASA document came up in one of my searches. It contains the torque values you seek.

https://ntrs.nasa.gov/api/citations/201 ... 003491.pdf

I do appreciate the link. I think those values could be useful reference for avoiding failure of body screws and clip screws on knives. The pivot, as noted, would likely not apply.

I understand that fasteners themselves have varying torque specs to avoid failure and those values are used by manufacturers during their assembly process but I still think it could benefit the end line user to also be aware of those values if they're doing their own maintenance.

That publication from NASA notes that those table were created to have something more reliable and repeatable than feel alone. That was kind of my idea for using a torque wrench with the pivot.

"... Usually, the indications when tightening under these conditions are just “hand tight” or “wrench tight” or “snug." However, these are not accurate designations since they have so many variants between person, location,
etc. A defined reference chart for torqueing to a proper value is necessary to have consistency and prevent
failures." - Page 1: Introduction

Maybe a torque wrench is just overkill and overcomplicating something like a knife pivot. Like using a sledgehammer to crack a peanut. Going by feel obviously works for so many of us; it works for the pivot screw and everything else really.

That's why I question if actually knowing the particular torque spec of your desired "blade movement" would help to be able to repeat that action during future maintenance. If judging by feel alone is sufficient enough for our personal needs, that's fine, it clearly works but I also don't see a disadvantage to the capability of quantifying it.

The way tolerances stack I think that torque value for the same “tightness” between two knives is going to make a spec useless. It’s like telling someone how hard to push the brakes to stop a car at a stop sign.

Plus I’m pretty sure the difference between too tight and just right is like 1/10th of a foot-lb. It just has to be dialed in my hand.

Right and that's totally fair. The results of using a torque wrench for the pivot would be relatively unique to each individual knife and likely not result in a value that can be shared between others.

There are torque wrenches capable of making very fine scale measurements though. If we were to dial in our own knives using a fine scale digital torque wrench, it would at least provide us with a baseline to aim for the next time we did maintenance. Again though, I understand how this might be overcomplicating the whole process when it's ultimately going to come down to feel anyway.

Always an advantage to having a baseline and way to measure.

Majority of people have absolutely zero "feel" when it comes to tools and hardware.


I haven't seen this video referred to of the Spyderco worker using a tool to tighten hardware, but I'd bet money it is simply a torque limiting driver, not specifically a torque measuring tool. Some basic hand tools are designed now to spin once a torque value is attained, assuring that things are not overtightened exceeding beyond that set value. This is great for anyone who may have a "lack of feel".

[SRT392HEMI]

Blue locktite has always worked for me.

[vivi]

Blue locktite has always worked for me.

Does for me too.

But that's not the point of this thread - which most folks seem to be missing.

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I took apart two knives this past week. A Military 2 and a different brand knife about the same size.

I didn't loctite either of them (half the replies missed this from the first post).

The off brand knife I carried for two or three days and used it a bunch. It worked great.

I tried to do the same with the Military 2. It became unsafe to carry and use after opening and closing it 15-20 times.

I'm wondering why there is such a difference in how the two pivot screws behaved under similar conditions?

---------------------

So this thread isn't about loctite. It isn't about torsion control wrenches like I use on my emonda. It isn't about being unable to rectify the issue of the Military 2 or 1 pivot screw coming out on its own.

I can fix the problem.

This thread is asking, why is this a problem in the first place?

I own many knives that function flawlessly without even thinking about using loc-tite, and I'm wondering what makes them behave so different than Spydercos in this respect.

[Danke]

Anyone who's worried about an issue with a pivot should send the knife to Golden.

I have 100+ folding knives, almost all Spyderco including a few of the Military category. I can only recall one knife that needed special treatment with Loctite. And out of that stack of knives many are tool steel so they get taken apart to clean and inspect the pivot area. That knife in particular is a Dodo.

The very worst loosening pivot knife I own is a Strider AR.

[vivi]

Anyone who's worried about an issue with a pivot should send the knife to Golden.

I have 100+ folding knives, almost all Spyderco including a few of the Military category. I can only recall one knife that needed special treatment with Loctite. And out of that stack of knives many are tool steel so they get taken apart to clean and inspect the pivot area. That knife in particular is a Dodo.

The very worst loosening pivot knife I own is a Strider AR.

Wish that were my experience. The Military 1's I've owned were so bad in this respect I've had pivot screws fall out at work when I was too busy to notice them coming loose on their own.

Haven't had great luck with sending knives to Golden, so I try to address issues myself or get a refund.

[Evil D]

Blue locktite has always worked for me.

Does for me too.

But that's not the point of this thread - which most folks seem to be missing.

---------------------

I took apart two knives this past week. A Military 2 and a different brand knife about the same size.

I didn't loctite either of them (half the replies missed this from the first post).

The off brand knife I carried for two or three days and used it a bunch. It worked great.

I tried to do the same with the Military 2. It became unsafe to carry and use after opening and closing it 15-20 times.

I'm wondering why there is such a difference in how the two pivot screws behaved under similar conditions?

---------------------

So this thread isn't about loctite. It isn't about torsion control wrenches like I use on my emonda. It isn't about being unable to rectify the issue of the Military 2 or 1 pivot screw coming out on its own.

I can fix the problem.

This thread is asking, why is this a problem in the first place?

I own many knives that function flawlessly without even thinking about using loc-tite, and I'm wondering what makes them behave so different than Spydercos in this respect.

I think there was an answer to the question, it's because most Spyderco's use pivot designs that can't be tightened all the way down while still being able to move the blade.

Whether its a bushing pivot or a D pin, they're all "perpetually loose" because they're never completely tightened down. Thread locker helps but unless you use the red liquid of death that Spyderco used to use then it'll probably still fail over time after repeated stress like shock from opening and flex.

If the other knife didn't have this problem then it must have a different pivot design that doesn't work the same way. If other Spyderco's don't have this problem, then I'd ask if they use the same pivot design as a Military 2. Maybe this is more common with bushing pivots?

I will say, I've never had them loosen as fast as you're talking about and when I was doing towing I'd have days where I used the crap out of my knives and I never had one loosen to the point of being unsafe. Even the Military 2 I've been carrying, I've used it quite a bit, I just cut up a bunch of that big heavy triple wall box today, and before I typed this out I checked the pivot and there wasn't any blade play but I was able to tighten it down even further than the factory had it (haven't taken this one apart or adjusted anything yet). I bet now that I've broke that screw loose it'll loosen up more.

I'm not saying I don't have them loosen, just that it takes a looong time for me to even notice, and I usually notice it because I'm checking for blade play and that's the indicator that the pivot loosened up. I've certainly never had one come so loose that anyone would call it unsafe or like the screw is going to fall out.

[Pacu0420]

Had that problem with my Para3 that I put Flytanium scales on. None of my other Spydercos do this. Anyway, a dab of blue thread locker fixed it right up. No more loose pivot.

[olditguy]

Never had a problem with any of my Spyderco's, but I stopped carrying another manufacturers knives due to this very reason.

[gooeytek]

I take my Spydercos apart frequently for scale swaps, maintenance, etc. I don't re-apply loctite ever, and I haven't noticed this problem. Then again, I'm not in the pursuit of drop-shut action. I like it when my knives have that slow glide as the blade closes, or needs some minimal assist.

[gooeytek]

double-tap.

[vivi]

I take my Spydercos apart frequently for scale swaps, maintenance, etc. I don't re-apply loctite ever, and I haven't noticed this problem. Then again, I'm not in the pursuit of drop-shut action. I like it when my knives have that slow glide as the blade closes, or needs some minimal assist.

That's where I set mine to as well, but I can't go a day without loctite or the pivot screw is at risk of working itself so loose it just falls off the knife.

[Mushroom]

We didn't miss the point of the thread... We just don't have the answer you wanted to hear.

It sounds like something is wrong with your knife. It is not normal for a knife to become "unsafe to carry" after opening it 15-20 times. Might be time to contact warranty and repair about this one if you're unable to resolve the issue yourself.