Detent - How weak is too weak?

[Actinolite]

I'd rather not be able to inertia open my knives. It's not something I do on purpose and I think if it's strong enough to prevent that then it's probably strong enough to keep me happy.

Agree completely. It took one near accident to make me realize that flickable knives might be fun to play with, but to carry, I prefer something that'll reliably stay closed.

[Mushroom]

I know it's not an option for the Kapara but one solution to prevent a knife from opening in pocket is carrying tip down when possible.

[zhyla]

I don't think there's any lock that has some kind of detent mechanism that can't be shaken out with enough effort :D. But I guess he meant a reasonable shake and most of my liner/frame/compression locks can do that.

Yeah, I guess what I really meant is any lock type that doesn't have a lot of friction is going to rely on the lock detente and that's never going to be enough to hold back a firm shake.

Pretty much just backlocks that stay shut for me.

[attila]

When I had a folder (61 HRC Z-wear) that opened too easily, I took a tiny carbide bit and deepened the detent divot on the blade a little bit. Worked great!

[Scandi Grind]

When I had a folder (61 HRC Z-wear) that opened too easily, I took a tiny carbide bit and deepened the detent divot on the blade a little bit. Worked great!

This is also exactly how you would address a weak detent on a firearm if it were a similar situation, say a safety detent for example. If it works on guns then it should work on knives. +1 for this strategy, just go slow and go careful, you can't put material back!

[Spyderbot_matrix]

If the locking mechanism needs a bluepill.. but that’s only good for a few hours..

I kid- if the knife giving emerson vibes and that isn’t a feature, get tactical rubber bands to keep it from opening (for now)

You can buy FG:1 tungsten carbide dentist drill bits to deepen the detent, and use the lowest setting on the dremel to avoid skipping. Then adjust the lockbar if the click isn’t positive enough

[silver & black]

If you carry tip up and slide the knife all the way against the side of your pocket.... I'm not sure how the blade opens??? Even if it does, the side of your pocket will not let it open so far as to cut you, IMO.

[silver & black]

When I had a folder (61 HRC Z-wear) that opened too easily, I took a tiny carbide bit and deepened the detent divot on the blade a little bit. Worked great!

I do the same.

[Actinolite]

If you carry tip up and slide the knife all the way against the side of your pocket.... I'm not sure how the blade opens??? Even if it does, the side of your pocket will not let it open so far as to cut you, IMO.

That is exactly the only way I now carry any knives with ball-detent for closing. I don't carry them often, because I still prefer the security of a backlock...lockback? Whatever. In fact for well over a year, the only detent-closed knives I've been carrying regularly are my comp lock Lil Natives in my 5th pocket, clip removed. The pocket feels tight enough to keep them closed. However, since I bought my first backlock Lil Native, the comp lock versions are in semi-retirement. Most of the time, when I need a larger knife I'll carry a Native 5. Larger than that, I'd prefer a fixed blade, but I will carry a LeafJumper or Manix 2 occasionally.

[silver & black]

If you carry tip up and slide the knife all the way against the side of your pocket.... I'm not sure how the blade opens??? Even if it does, the side of your pocket will not let it open so far as to cut you, IMO.

That is exactly the only way I now carry any knives with ball-detent for closing. I don't carry them often, because I still prefer the security of a backlock...lockback? Whatever. In fact for well over a year, the only detent-closed knives I've been carrying regularly are my comp lock Lil Natives in my 5th pocket, clip removed. The pocket feels tight enough to keep them closed. However, since I bought my first backlock Lil Native, the comp lock versions are in semi-retirement. Most of the time, when I need a larger knife I'll carry a Native 5. Larger than that, I'd prefer a fixed blade, but I will carry a LeafJumper or Manix 2 occasionally.

I like lockbacks too. I have an Endura and a Native 5 that I carry all the time.

[silver & black]

If you carry tip up and slide the knife all the way against the side of your pocket.... I'm not sure how the blade opens??? Even if it does, the side of your pocket will not let it open so far as to cut you, IMO.

That is exactly the only way I now carry any knives with ball-detent for closing. I don't carry them often, because I still prefer the security of a backlock...lockback? Whatever. In fact for well over a year, the only detent-closed knives I've been carrying regularly are my comp lock Lil Natives in my 5th pocket, clip removed. The pocket feels tight enough to keep them closed. However, since I bought my first backlock Lil Native, the comp lock versions are in semi-retirement. Most of the time, when I need a larger knife I'll carry a Native 5. Larger than that, I'd prefer a fixed blade, but I will carry a LeafJumper or Manix 2 occasionally.

I like lockbacks too. I have an Endura and a Native 5 that I carry all the time.

Looking tyo add a Native Chief and an Endela in K390 when tit becomes available again.

[silver & black]

If you carry tip up and slide the knife all the way against the side of your pocket.... I'm not sure how the blade opens??? Even if it does, the side of your pocket will not let it open so far as to cut you, IMO.

That is exactly the only way I now carry any knives with ball-detent for closing. I don't carry them often, because I still prefer the security of a backlock...lockback? Whatever. In fact for well over a year, the only detent-closed knives I've been carrying regularly are my comp lock Lil Natives in my 5th pocket, clip removed. The pocket feels tight enough to keep them closed. However, since I bought my first backlock Lil Native, the comp lock versions are in semi-retirement. Most of the time, when I need a larger knife I'll carry a Native 5. Larger than that, I'd prefer a fixed blade, but I will carry a LeafJumper or Manix 2 occasionally.

I like lockbacks too. I have an Endura and a Native 5 that I carry all the time.

I like lockbacks too. I have an Endura and a Native 5 that I carry all the time.

Looking to add a Native Chief and an Endela in K390 when it becomes available again.

[silver & black]

That is exactly the only way I now carry any knives with ball-detent for closing. I don't carry them often, because I still prefer the security of a backlock...lockback? Whatever. In fact for well over a year, the only detent-closed knives I've been carrying regularly are my comp lock Lil Natives in my 5th pocket, clip removed. The pocket feels tight enough to keep them closed. However, since I bought my first backlock Lil Native, the comp lock versions are in semi-retirement. Most of the time, when I need a larger knife I'll carry a Native 5. Larger than that, I'd prefer a fixed blade, but I will carry a LeafJumper or Manix 2 occasionally.

I like lockbacks too. I have an Endura and a Native 5 that I carry all the time.

Looking to add a Native Chief and an Endela in K390 when it becomes available again.

[Red Leader]

I think the initial question is pretty personal. I can shake open every folding knife I have except for a higonokami and my Milwaukee fastback that is locked by a button. This also includes all Spyderco lockbacks, multiple Manixs, etc.

That said, I think there is a gut feeling when it is just too weak. A lot of the detent-based Taichungs have struggled with weak detents, relative to all the other Spydercos I have. I don't think it is an insurmountable problem, but when you pay close to $300 it might be a bit off putting to have to take it all apart to either widen the detent hole or bend the lockbar, both of which are good suggestions btw.

As I continue in my EDC and knife journey, it seems like there is a constant maturing towards a less-flashy lockback instead of a desire for more detent-based flickability. It is probably age-related. Reliability tends to be prioritized over looks as you grow older (wiser?), I think it is just a natural progression. I tend to roll my eyes at all those 30-sec long reverse flick reddit videos that all look the same, and instead when I see someone slow roll a Native, I think 'that person knows'.

Nevermind that my main EDC is a PM2 and I don't own a Native.

[burley_c]

After I originally posted this question I thought a lot, perhaps too much about safety and compression locks, and found a handful of stories online about compression lock knives opening in people's pockets. Doesn't seem super common, but it was concerning. So I got curious and ordered a $20 trigger pull gauge on Amazon and did a bit of testing on a few of my spydercos. Much to my surprise the detent strength on my compression lock knives was almost identical to my back locks. Here are my unscientific results:

Comp Locks
Sage 5 LW: ~2 lbs
PM2 LW: ~2 lbs
Military 2: ~3 lbs*
Kapara (factory 2nd): ~0.5 lbs

Back Locks
Delica 4: ~2.5 - 3 lbs
Stretch 2 XL: ~2 - 2.5 lbs
Dragonfly: ~2 lbs
Chaparral: ~1.5-2lbs

CCBL
Manix 2 LW: ~2 lbs

Conclusions

I have to say, this was surprising. With the exception of the Kapara that I knew was a problem, the detent strength did not vary much by lock type. This is a guess at this point, but the reuslts lead me to believe that the improved closing bias and safety of the back lock comes from the fact that on a back lock knife the same force is being applied over a longer travel distance of the blade (45 degrees roughly) while rotating into the open position when compared to the compression lock knives.

The Military 2 had the strongest detent, but that's only because it had a weak one to start and I made the detent hole bigger using some of the pointers in this thread. Unfortunately, despite my best efforts to go slow, I didn't go slow enough and now there's some slight play in the blade (lash??) when closed. That said, I'll take it over the possibility of a knife coming open unexpectedly.

The detent on the Kapara was MUCH worse than I had imagined so I'm going to order some better bits for my dremel and try to very slowly enlarge the detent ball hole. If that doesn't work, I may just need to regulate to a permanently open paring knife that lives in my kitchen knife block.

My biggest takeaway from all this is that the back lock is an under appreciated humble warrior. It's a simple battle-tested design that keeps the knife open when you want it open and closed when you want it closed.

[Red Leader]

After I originally posted this question I thought a lot, perhaps too much about safety and compression locks, and found a handful of stories online about compression lock knives opening in people's pockets. Doesn't seem super common, but it was concerning. So I got curious and ordered a $20 trigger pull gauge on Amazon and did a bit of testing on a few of my spydercos. Much to my surprise the detent strength on my compression lock knives was almost identical to my back locks. Here are my unscientific results:

Comp Locks
Sage 5 LW: ~2 lbs
PM2 LW: ~2 lbs
Military 2: ~3 lbs*
Kapara (factory 2nd): ~0.5 lbs

Back Locks
Delica 4: ~2.5 - 3 lbs
Stretch 2 XL: ~2 - 2.5 lbs
Dragonfly: ~2 lbs
Chaparral: ~1.5-2lbs

CCBL
Manix 2 LW: ~2 lbs

Conclusions

I have to say, this was surprising. With the exception of the Kapara that I knew was a problem, the detent strength did not vary much by lock type. This is a guess at this point, but the reuslts lead me to believe that the improved closing bias and safety of the back lock comes from the fact that on a back lock knife the same force is being applied over a longer travel distance of the blade (45 degrees roughly) while rotating into the open position when compared to the compression lock knives.

The Military 2 had the strongest detent, but that's only because it had a weak one to start and I made the detent hole bigger using some of the pointers in this thread. Unfortunately, despite my best efforts to go slow, I didn't go slow enough and now there's some slight play in the blade (lash??) when closed. That said, I'll take it over the possibility of a knife coming open unexpectedly.

The detent on the Kapara was MUCH worse than I had imagined so I'm going to order some better bits for my dremel and try to very slowly enlarge the detent ball hole. If that doesn't work, I may just need to regulate to a permanently open paring knife that lives in my kitchen knife block.

My biggest takeaway from all this is that the back lock is an under appreciated humble warrior. It's a simple battle-tested design that keeps the knife open when you want it open and closed when you want it closed.

Have you also tried bending the lock bar a bit? I have a Lil' Temperance 3 that had a pretty weak detent, and while it also has some other issues, changing the lockbar strength just slightly made an appreciable difference.

[GarageBoy]

As someone who carries bottom of pocket only - it's slip it's and back locks only (maybe a crk frame lock that's super stiff) - if it's an axis style or compression lock - it rides in my 5th pocket (wrangler work pants have giant 5th pockets)

[navin johnson]

After I originally posted this question I thought a lot, perhaps too much about safety and compression locks, and found a handful of stories online about compression lock knives opening in people's pockets. Doesn't seem super common, but it was concerning. So I got curious and ordered a $20 trigger pull gauge on Amazon and did a bit of testing on a few of my spydercos. Much to my surprise the detent strength on my compression lock knives was almost identical to my back locks. Here are my unscientific results:

Comp Locks
Sage 5 LW: ~2 lbs
PM2 LW: ~2 lbs
Military 2: ~3 lbs*
Kapara (factory 2nd): ~0.5 lbs

Back Locks
Delica 4: ~2.5 - 3 lbs
Stretch 2 XL: ~2 - 2.5 lbs
Dragonfly: ~2 lbs
Chaparral: ~1.5-2lbs

CCBL
Manix 2 LW: ~2 lbs

Conclusions

I have to say, this was surprising. With the exception of the Kapara that I knew was a problem, the detent strength did not vary much by lock type. This is a guess at this point, but the reuslts lead me to believe that the improved closing bias and safety of the back lock comes from the fact that on a back lock knife the same force is being applied over a longer travel distance of the blade (45 degrees roughly) while rotating into the open position when compared to the compression lock knives.

The Military 2 had the strongest detent, but that's only because it had a weak one to start and I made the detent hole bigger using some of the pointers in this thread. Unfortunately, despite my best efforts to go slow, I didn't go slow enough and now there's some slight play in the blade (lash??) when closed. That said, I'll take it over the possibility of a knife coming open unexpectedly.

The detent on the Kapara was MUCH worse than I had imagined so I'm going to order some better bits for my dremel and try to very slowly enlarge the detent ball hole. If that doesn't work, I may just need to regulate to a permanently open paring knife that lives in my kitchen knife block.

My biggest takeaway from all this is that the back lock is an under appreciated humble warrior. It's a simple battle-tested design that keeps the knife open when you want it open and closed when you want it closed.

The actual pull weight to overcome a detent is not a direct comparison to a backlock. Once you’ve overcome, the detent, the blade is more or less free with little resistance. A back lock can often be opened 20ish% and still pull it itself closed

I have had a CBBL come out from IWB partially opened

One of the worst injuries I’ve seen pictures of was a guy whose PM2 opened in his pocket. It was tip down and caught him on the way out.

Knives are tools and tools are dangerous if they’re not used right be careful

[vivi]

If you carry tip up and slide the knife all the way against the side of your pocket.... I'm not sure how the blade opens??? Even if it does, the side of your pocket will not let it open so far as to cut you, IMO.

Happened to me more than once. Pockets are a thin sheet of very flexible fabric and I'm pretty active. It's not as foolproof of a carry method as many think.

[amue]

"Too weak" is a matter of personal requirements.
For me, most detents are "too weak", because there is a non-negligible probability that the blade will open when the knife is dropped. This is true for ball detent based locks (liner, frame, compression), but others suffer from the same problem. Some axis-type lock specimens are even worse.

The only lock type i've found reliable in that regard is the back lock (and its cousins like the Tri-Ad lock).

Meanwhile, what others have posted about increasing the detent strength is true. I've done it dozens of times.

There are a number of factors to be considered here:
- the depth of the ball engaging the hole, which is a function of the amount of ball protruding, the size and depth of the hole and the alignment of the ball and the hole
- the angle of the edge of the hole - it should be nice and crisp
- the tension of the lock bar

Possible fixes include:
- enlarging the hole
- increasing liner tension
- re-fitting the ball so it protrudes more
- bending the liner slightly towards the back of the handle