Which is the stronger stop pin?

I'd like CM to I.D. those 2 knives. They both look like pretty stout folders. :)
 
FlaMtnBkr said:
I think it depends on the diameter of the stop pin and how strong it is compared to the thumb stud. If the thumb stud is screwed together I would think a solid stop pin is always going to be stronger.

If you think about it, a stop pin is rounded and sticks in a curved hole to transfer forces to the liners. Just like the rounded thumb stud and the curved section it rests against in the liners. Yes the contact area is pretty small between blade tang and stop pin. But the contact area between the blade and the thumb stud is also going to be fairly small, at least in the thumb studs that I have seen that screw together. If it is pressed in then it will increase the surface area quite a bit.

I wonder why makers don't put a curved section in the tang to wrap around the stop pin a little and increase surface area? I bet it would drastically decrease the amount of 'peening' of the stop pin that puts a flat spot in the stop pin and can increase lock engagement on a frame lock.
Click to expand...


Yeah, all they have to do is to grind a curve with same diameter as stop-pin. Small effort for large rewards :)
 
The first is a Daryl Ralph and the second is a Greg Lightfoot. Not positive on the model names though.

Yes those types of indentation are what I was talking about. When looking at the forces you can't just look at the thumb stud/ handle joint and the blade tang/ stop pin you have to look at all the joints that connect the blade to the liners of the knife. It doesn't matter if one has a very strong interface if it also has a quite weak one.
 
I don't think it really matters either way so long as they're well made. I've had BMs and Kershaws with frame mounted stop pins and Striders and CRKTs with thumb stud stops. No problems with any of them.

The Striders are a solid pin that's pressed through the blade but most of the thumb stud ones screw together. There is usually a shoulder machined into the stud to support it in the blade so it's not just the screw taking all the stress. I think to break the screw you would have to be doing something seriously stupid with your knife. It seems that this way would hasve less side to side flex.

If seen frame mounted stop pins get a flat spot worn in them from flicking the knife open, and that can effect the lock, but I've never seen one break off. Even if you do get a flat spot you can usually just rotate it and it's good as new. Benchmade uses a hexagonal stop pin on the Nitrous assisted opening knives. I think having the blade tang contact the flat surface might help to stop the problem of deforming the stop pin.

I personally prefer the thumb stud style but mostly just because of the cleaner less cluttered design you can get with the handle.
 
If the shape and diameter are the same, the thumbstud that is anchored on both ends (in the frame) will be stronger than the thumbstud that is anchored at only one end. Being anchored at only one end makes it more prone to torsional stress. It would be interesting to see what the yield strength would be, comparing a single thumbstud anchored at both ends with two thumbstuds anchored at only one end.
 
cziv said:
I'd like CM to I.D. those 2 knives. They both look like pretty stout folders. :)
Click to expand...

First one is a HD Maxx and the last one is a Lightfoot.
 
Cotherion said:
Yeah, all they have to do is to grind a curve with same diameter as stop-pin. Small effort for large rewards :)
Click to expand...

Naturally, that's how Kershaw does the Shallot, Blur, Offset, JYD's, ZT0200, and likely a whole lot more.

I have a decent pic of the Offset.

IMG_6863.jpg
 
It should be noted that the Ball Bearing lock has a very large contact area for the blade stop as well. On the D'Allara the blade stop is the top of the steel back spacer that extends the whole length of the handle.
 
Yup Joshua J. Some makers have got the right idea. I have good opinions and that's why of those you mentioned, I have two of everything at one time except for the Blur. Kershaw has less of the little things which irritate me.

Trying to collect all of the BB-lock models of spyderco. Unfortunately though the contact area is large, in the BB-locks they would have been perfect if they had either more screw attachments or more little pins in which transfer stress.
 
How has this not come up yet?

Look at the cut out of the American Lawman that meets the stop pin.

HPIM2980.jpg


As to Charlie Mike's blades, I like the blade mounted stops better of the two designs.
 
Don't the ZT 0300 series use the thumbstuds to act as stop pins against the frame? Look like it anyway.
 
I'm not sure if stop-pin failure is a realistic concern in an over-built knife, but if it is it would seem pretty trivial to design a knife that incorporated both features.
 
Here's another style. You can see the stop pin is the random hole near the pivot. There is a track on the tang of the blade on the inside which follows this pin. When the track ends, the pin stops the blade. So instead of stopping the blade from the back, it stops it from the front. I don't know if this is stronger or weaker.

1720.jpg
 
Well, I noticed something about my Leek after I used it earlier today... The frame lock normally stops at about the 50% mark of the tang. When I used it to push down hard on something that I was cutting, it moved in further.

I don't recall this ever happening to any of my liner/frame lock knives that use a stop pin. So this serves to confirm my preference for stop pins, including those similar to the ones on the JYD.
 
THG said:
Well, I noticed something about my Leek after I used it earlier today... The frame lock normally stops at about the 50% mark of the tang. When I used it to push down hard on something that I was cutting, it moved in further.

I don't recall this ever happening to any of my liner/frame lock knives that use a stop pin. So this serves to confirm my preference for stop pins, including those similar to the ones on the JYD.
Click to expand...

You sure you didnt just grip the handle tighter and push in the lockbar a bit more? If not than thats interesting. I honestly dont have a preferance either way because the stop pin is probably one of the last things to break under stress. The lockbar cutout area and pivot would likely fail first.
 
Are any of us strong enough to break or deform either one with our muscle power other than possibly by chopping? I'm pretty sure I'm not, and nobody ever accused me of being a weakling.
 
THG said:
I don't recall this ever happening to any of my liner/frame lock knives that use a stop pin. So this serves to confirm my preference for stop pins, including those similar to the ones on the JYD.
Click to expand...

No it doesn't.
I've had both styles of pin/stop do the exact same thing.
It will depend on tang ramp angle and how hard the lock kicks over when opened.
It will move more if you open it lightly and then use it than if it's slammed open hard.
Neither style of pin/stop is immune to what you experienced though.
 
cziv said:
Don't the ZT 0300 series use the thumbstuds to act as stop pins against the frame? Look like it anyway.
Click to expand...

My Kershaw scallion uses the studs for stop pins and it has a very solid lockup, they defiantly got it right.
 
You must log in or register to reply here.
Back
Top