Detents

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Jan 6, 2016
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I posted this over on the Spyderco Forums. I figured I'd post it here for those who don't get over there.

....Particularly ball detents. I see this subject discussed quite a bit. It's definitely something I pay attention to when I get a new knife.

Recently, in one of the Sliverax threads, someone asked if the Sliverax has a strong detent. Another member responded that he thinks the detent's comparable to a PM2. So I compared my Sliverax one of my PM2s (S30V/DLC) and they did feel similar. Then I compared the SA to my PM2 Cruwear, which has a noticeably strong detent, and the latter was the obvious winner. So then I started wondering how I could actually measure the difference in detent strength of the various models I have. It occurred to me that I could use one of my most used tools from my other favorite hobby, shooting. So I got out my trusty trigger pull gauge and started doing some testing. I thought some of you might be interested in seeing the results.

Keep in mind that these are only the results for my particular knives. Detent strength definitely does vary from knife to knife as I think the results show. If you happen to have a trigger pull gauge or a similar way to measure detent strength please feel free to share your results. I think it would be interesting to compare.

Also, while this test was hardly a scientific test, I did my best to be as consistent as possibe when checking each model. I held the closed knife in my left hand with pivot facing down. Then I hooked the arm of the trigger pull gauge through the Spydie hole, tightened things up until I had a pre-load of about 8 oz, and then I pulled with gradual pressure until the detent broke and blade opened. I measured each knife several times. I was surprised by how consistent the detent broke on each model.

The results below are in the order that I tested each model.

Sliverax - 17 oz
Paramilitary 2 S30V/DLC - 20 oz
Paramilitary 2 Cruwear- 36 oz
Para 3 S30V - 22 oz
Para 3 Cruwear - 24 oz
Mantra - 14 oz
Sage 1 - 22 oz
Sage 2 - 20 oz
Sage 5 - 20 oz
Gayle Bradley (#1) - 22 oz
Gayle Bradley (#2) - 22 oz
Cat (440C) - 17 oz
Firefly - 33 oz

Some knives without detent ball just for fun:

Manix 2 LW S110V - 24 oz
Manix 2 LW XHP - 26 oz
Manix 2 LW BD1 (black) - 23 oz
Manix 2 LW BD1 (translucent blue) - 31 oz
Manix 2 G10 S30V - 23
Sage 3 - 8 oz

I thought the results for the Sage 3 were interesting, I knew the detent was light but I was surprised that it was only 8 oz.
 
Very cool comparison. Thanks for sharing your results. My Para 3's always seemed harder to open than my PM2's. Just curious have you adjusted any of the pivot screws on the knives or is this test pretty much out of the box what you see is what you got. For example on some of my PM2's I loosen the screw slightly so the blade will move freely when the lock is disengaged.

On my Sliverax the action is very smooth compatible to my Domino and my Mantra.

Thanks again for sharing your info.
 
Interesting! Is this something manufacturers should use on the assembly line to dial in every knife. If it's under 20oz fix detent. Kinda thing.
 
This is awesome, considering the amount of crossover between guns and knives as hobbies, I would love to see more people doing this. It's a really useful, sort of empirical way of describing a detent. It seems especially easy to do with a Spydiehole.
 
Just curious have you adjusted any of the pivot screws on the knives or is this test pretty much out of the box what you see is what you got. For example on some of my PM2's I loosen the screw slightly so the blade will move freely when the lock is disengaged.

Some I've adjusted slightly but a few are as they came from the factory. I haven't touched the pivot on the P3 S30V, PM2 Cruwear, or the Mantra. They were perfect right out of the box.

On my Sliverax the action is very smooth compatible to my Domino and my Mantra

My Mantra is definitely smoother than my Sliverax but the SA is pretty smooth too.
 
Odd that the only flipper on the list had a rather light detent.

Actually two flippers on the list but both have relatively light detents. Both flip and flick great by the way. I wouldn't mind a slightly stronger detent on both but not sure I'd change anything at this point.
 
I actually did much the same with several of my knives ... used two different trigger pull gauges just out of curiosity.

Now alot of my knives wern't Spydercos so with some others ZTs or Hinderers etc ...

I used a short piece of bank line and attached to both thumbstuds and centered the trigger pull gauge trying to make sure it was even ... and on flippers I attached to the Flipper tabs (if a knife had both a flipper tab and thumbstuds I tried both ways) ...

I didn't record the numbers so can't give those but did note some fairly substantial differences ... and some of those I could correct by adjusting the pivot and it gave me pretty consistant readings after adjusting pivots so most knives to get a good detent resistance were similiar.

And as you stated ... my tests were not at all scientific and could have allowed for some difference in results ...

But I did notice it actually seemed to matter more how smooth the action was to get a good smooth full flip with a solid lock up ... then the amount of force it took or the detent pressure.

Did you notice at all ... or have any knives that seemed to fly open and lock great even with weaker detents? Or were your results in which knives opened and locked solid match directly to those with a stronger detent? I am just curious if you noticed some with lighter detents but that were very smooth still opened with enough snap to lock up solid?
 
Actually two flippers on the list but both have relatively light detents. Both flip and flick great by the way. I wouldn't mind a slightly stronger detent on both but not sure I'd change anything at this point.
Oops, missed the Mantra.
 
Did you notice at all ... or have any knives that seemed to fly open and lock great even with weaker detents? Or were your results in which knives opened and locked solid match directly to those with a stronger detent? I am just curious if you noticed some with lighter detents but that were very smooth still opened with enough snap to lock up solid?

All the knives tested lock up solid regardless of how I open them. The two with the lightest detents (Sliverax & Mantra) flip open well and flick open even better.

When I first received each my first though was that they could use a little stronger detent but that before I figured out how to flip 'em. The Mantra was my first flipper and I was trying to use a light switch method to flip when clearly (IMO) it's designed to use the push button method. It flips open with authority that way. When I recently got the Sliverax I tried to use the push button method at first and I could get it to open but it was kind of lackluster plus I got a little pinch from the lock. Then I went to the light switch method and it opens much better. Since they both open so well all my thoughts about needing a stronger detent have gone away. They're fine the way they are and it's a non-issue for me.
 
Thanks for sharing your results ... I came to much the same conclusions you did ... I didn't test any Sebenzas because they have a bit different motion and I wasn't sure I could replicate it this way.

But some ZTs the flipper was fairly light but the thumbstuds increased the pull weight quite a bit ... which I knew already from use that some ZTs are very difficult to open with the thumb studs ... but then again they aren't really made to on their flippers.
 
Ball detents can be all over the place and they're all suspect. I've said many times that I'd like to see a frame/liner lock knife use a slipjoint type mechanism as a closed detent. It may not have Shabazz approved silky smooth action but it would surely appeal to those of us who like their knife to stay closed through life's tumbles and rolls!
 
No manufacturer has managed to make a universal detent strength. I even own CRK's with major variations in detent. When someone can finally perfect it at an acceptable additional cost to knife making, the knife industry will grow that much better.
 
Another thing to consider is replacing the detent. We've had good luck with replacing the (sometimes softish) stainless detents with a ceramic ball. It can be a little fiddly to do, and the knife needs to have a through-hole for the detent, but it's something you can do with a c-clamp and some stable hands
 
I like strong detent. I prefer backlock models by a large margin. If I can shake it open, like many a well used PM2, I don't have the trust level I like. Compression locks seem to me to have the lightest detent in the Spyderco line up. Possibly some liner locks other than the Millie? Millie has good detent
 
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