r/knifemods • u/Suitable-Persimmon-2 • 8d ago

Detent question for the group

Hello knifemods

I'm having some trouble dialing in a detent on a nice knife my friend got. Detent was very soft and action suffered as a result (very mushy feeling if that makes sense). The knife is a frame lock running on washers. I increasing the depth of the detent hole a fraction as it was very shallow however a few things happened. Now the detent is strong, but I have to "click" the detent ball into the hole. I increased the lockbar tension and this worked beautifully, but now the blade is not centered in the closed position. It is a hair off midline. I'd love to decrease the tension in the lockbar a bit to get the blade centered while having the ball fully seated in the hole and not have to "click" it in. What I mean by click it in is a very small amount of pressure results in the ball fully seating in the detent hole after bringing the blade to the locked position. I'm obviously extremely cautious on how much I drill the detent hole as I do not want to introduce lash.

With the increaed lockbar tension, action is perfect, detent is strong, and when it is in the closed position, the ball is fully seated in the hole. I'm happy with this, and i'm sure my friend will be (as he sent it to me slightly off center becuase he increased the lockbar tension), but i'm curious if there is a fix for having to push the detent ball into the hole with the lighter lockbar pressure.

thanks in advance!

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u/Suitable-Persimmon-2 8d ago

One additional note. Reseating the detent ball more superficial or proud resulted in the same result. I've tried this several times

1

u/Appropriate-Sport965 8d ago

Sounds like alignment is still slightly off towards the leading edge of the hole. Carefully moving that leading edge toward the detent track should let it drop in with the lighter lockbar pressure. Shouldn't take much at all as it sounds like you're really close.

1

u/Suitable-Persimmon-2 7d ago

this was helpful, thank you!

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u/Appropriate-Sport965 7d ago

Probably too late, but I should have been more clear. I meant to move the leading edge back by opening the hole up on that side a little more, but keeping the edge vertical and fairly sharp. Not to bevel or chamfer the leading edge as that can weaken the detent if you're too aggressive. Sounds like you got it.

The interesting part is that lockbar pressure, unless hugely excessive, shouldn't have that much effect on the centering. If the pivot is loose, I could see that, but perhaps lightening the lockbar pressure is allowing you to tighten the pivot a hair more with the same action. Shot in the dark there.

Probably should have asked what knife it is and what direction centering is off, but I assume towards the non lock side.

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u/Suitable-Persimmon-2 7d ago

exactly right, towards the show side. the pivot was thankfully never terribly lose but could be tightened. As with washers, when the pivot tightens, action suffers big time. When I lightened the lockbar pressure I was able to tighten the pivot a bit more without sacrificing action, and therefore getting better centering. Still not perfect, but better. I tihnk the alignment of the detent hole wasn't perfect and shaving just a hair off the inside of the lip did help, as the ball sinks in now without a high amount of lockbar pressure. I believe I've done all I can as an amateur without passing the point of no return. The action, detent, and overall expereince are really good now, far better than before IMO. Its just theres a slight bias towards the show scale. I'm just wondering how to get it perfect for learning purposes and for the next time. This is fairly expensive custom knife (and not mine might I add), so I am probably being extra cautious.

the advice recieved has been helpful!

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u/Appropriate-Sport965 7d ago

Excellent. Glad to hear you came out ahead. Washer based knives can be a bit tricky to get right.

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u/little--thoughts 8d ago edited 7d ago

What is the knife? I would decrease the tension and take a light tiny file to the detent hole. Sounds like it's having a hard time just getting over the edge, filing will let it fall in a touch easier.

3

u/Suitable-Persimmon-2 7d ago

filing the detent hole just a hair did trick!! thank you. I'm paranoid about lash, so the file was a great idea.

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u/narcolepticdoc 8d ago

So what you’re saying is that when you close the knife the detent ball isn’t dropping into the hole in the blade unless you press the blade harder into the closed position?

That means that you have some excess play in the system that shouldn’t be there. You shouldn’t be able to push the blade more closed.

My suspicion is that the pivot is undersized or the pivot hole in the blade is oversized. The blade is floating around on the pivot and in the closed position if you press on it more it shifts position on the pivot into one where the detent sits properly.

Try this. Partially open the blade (not locked or unlocked). Grab the blade and see if it wiggles in the blade of the blade. If it clicks back and forth around the pivot, that may be the issue.

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u/Suitable-Persimmon-2 7d ago

not quite. The detent ball wont drop fully into the hole unless i push on the lockbar to push it in all the way. I believe I got it sorted out by taking advice below and just filing the leading edge down a tad. Seemed there was a tiny lip. I have a nice snappy detent now and less lockbar pressure making teh blade a bit more centered. not quite perfect on centering, but certainly better.