Stop Pins

timberweasel · Oct 30, 2016

I cannot think of one example of where the removal of material has ever made any structure stronger. 'Strong enough' is an entirely different concept...

-Brett

The Aflac Duck · Oct 30, 2016

Glenn056 said:
But I think it's pretty common sense that a knife with an internal stop pin system with a heavily milled out pivot area, is weaker than a knife with the pivot area still intact. Probably not suited for hard cutting task such as through thick cardboard or carpet or other tough materials that might require some twisting in order to cut through, as opposed to knives with an intact pivot area , using external bladestops or the conventional stop pin.

Sent from my ASUS_Z00AD using Tapatalk

And again, you're evidence for this is where? I've used an internal pin for all the things you've mentioned and more...

I don't know what a "hard use" knife is, so I can't offer anything there. Also, I don't need to "justify" my purchases, all my knives work great for what I do for a living:thumbup:

I guess people underestimate how strong steel is

I've seen pieces of steel much thinner than the milled out section of an internal stop pin being used as structural components requiring much more strength than a knife. If you're using your knife to the point of breaking your pivot (internal pin or not) then you are using the wrong tool to begin with...

The Aflac Duck · Oct 30, 2016

timberweasel said:
I cannot think of one example of where the removal of material has ever made any structure stronger. 'Strong enough' is an entirely different concept...

-Brett

Who said that removal makes it "stronger"? If the design is weaker, what are we comparing strength values to? I don't see any evidence that an internal pin is "inferior" other than the keyboard theories we have here

Biginboca · Oct 30, 2016

Blues Bender said:
I don't see any evidence that an internal pin is "inferior" other than the keyboard theories we have here

Obviously you won't be swayed, but the pics showing the missing material from the those blades pivot area is glaringly obvious evidence they are inferior in strength. You are arguing just to argue I won't post on this any more.

The Aflac Duck · Oct 30, 2016

Biginboca said:
glaringly obvious evidence they are inferior in strength.

What evidence? A picture? Lol!
This is like someone claiming a car isn't fast because it looks slow. Without driving it, how would you know?

I'm arguing to argue? Yeah right, you have no argument to begin with!

Vicarious Reality · Oct 30, 2016

Thetimefarm said:
I'm not sure that it really matters. I feel like when dealing with a well designed folding knife other pieces are going to break before the stop pin when the knife is under stress. .

Actually...... no

[video=youtube;874q2iFsvb8]https://www.youtube.com/watch?v=874q2iFsvb8[/video]

timberweasel · Oct 30, 2016

Blues Bender said:
Who said that removal makes it "stronger"? If the design is weaker, what are we comparing strength values to? I don't see any evidence that an internal pin is "inferior" other than the keyboard theories we have here

Who said that an internal pin is inferior? Inferior to what?

Mick_1KRR · Oct 30, 2016

Cold steel and ZT do stop pins correctly. Radius cut outs for the impact section of tang to stop pin. I think it's just lazyness for any manufacturer to have a flat surface smacking against a round pin surface, it will always develop a flat spot. I was really surprised to see that even Chris Reeve left this out of his designs. A simple little cutout solves a lot of issues, especially on frame locks where that flat spot has a big effect on the lockup. Chris Reeve could've avoided so much of the "do not flick our knives" fiasco because of the later lockup it was causing if the impact area had that proper radius and the stop pin was at the right hardness.

The Aflac Duck · Oct 30, 2016

Regarding external pins cracking the blade:

This is the number three thing we send knives back to manufacturers for. Not just ZT but all knives that have a thumbstud through the blade.

This is from a well respected dealer that hangs out here on BF. I'll leave the name anonymous.

Glenn056 · Oct 30, 2016

I agree, external bladestops might cause the blade to have a hairline crack due to shock. However, ive only heard that from striders. Hinderer, CRK Umnumzaan etc, i don't remember seeing any reports of such. Now, Im not saying any design is perfect. They all have their own flaws. But I initially was merely stating that of the internal stop pin, how vigorous cutting that might require some twisting to get into the material MIGHT cause the blade to snap at the pivot. External blade stops would be more suited as they provide side-to-side stability when doing such tasks.

Sent from planet Mars

Glenn056 · Oct 30, 2016

Blues Bender said:
If you're using your knife to the point of breaking your pivot (internal pin or not) then you are using the wrong tool to begin with...

What if a folder is all you have at the time? It is something that cuts, right? Not everyone has access to a chainsaw. Maybe you have to cut through that material in the nick of time?

Sent from planet Mars

The Aflac Duck · Oct 30, 2016

Glenn056 said:
What if a folder is all you have at the time? It is something that cuts, right? Not everyone has access to a chainsaw. Maybe you have to cut through that material in the nick of time?

Sent from planet Mars

Let's not make false-dilemmas, you know darn well the point I'm making...

Glenn056 · Oct 31, 2016

That for your uses, you don't have to do heavy cutting? That internal stop pins can serve you well for your uses? Great! Good for you. Im just talking about people who would need to do heavy cutting, people who for example, in the law enforcement or fire department that might need do things in a pinch. Hence, my opinion is that internal stop pins probably wouldn't be ideal for them, there are many reports of then using their folders to the limit if that at the time happen to be the only tool they have for the job. Prying open a jammed car door, windows, etc are common to an extent for them. So a stronger pivot would be ideal.

Sent from planet Mars

The Aflac Duck · Oct 31, 2016

It's funny you mention that, because 9/10 times an LEO is carrying a gas-station-special knife and not a $400 Strider

And for the record, I manage construction and do heavy cutting regularly.

mtangent · Oct 31, 2016

Glenn056 said:
I agree, external bladestops might cause the blade to have a hairline crack due to shock. However, ive only heard that from striders. Hinderer, CRK Umnumzaan etc, i don't remember seeing any reports of such. Now, Im not saying any design is perfect. They all have their own flaws. But I initially was merely stating that of the internal stop pin, how vigorous cutting that might require some twisting to get into the material MIGHT cause the blade to snap at the pivot. External blade stops would be more suited as they provide side-to-side stability when doing such tasks.

Sent from planet Mars

Nobody knows why the thumb studs make the blades crack. Stress risers, & ill fitting studs seem likely. This means the defect is there, before you start using it. So, is your knife strong, or not? You won't know until it breaks.

grownstar · Oct 31, 2016

They're all reliable designs, as far as I'm concerned. I'll just say that I feel more confident in the external stop pin/blade stop. And that's just my opinion.

timberweasel · Oct 31, 2016

Mick_1KRR said:
Cold steel and ZT do stop pins correctly. Radius cut outs for the impact section of tang to stop pin. I think it's just lazyness for any manufacturer to have a flat surface smacking against a round pin surface, it will always develop a flat spot. I was really surprised to see that even Chris Reeve left this out of his designs. A simple little cutout solves a lot of issues, especially on frame locks where that flat spot has a big effect on the lockup. Chris Reeve could've avoided so much of the "do not flick our knives" fiasco because of the later lockup it was causing if the impact area had that proper radius and the stop pin was at the right hardness.

I just had a closer look at my 21s. Both the large and small have a slight curve to the tang which nests with the stop pin on an arc--subtle, but it doesn't seem to be quite the case of a flat tang impacting on a round pin...

-Brett

johnnytoxin · Oct 31, 2016

Mick_1KRR said:
Cold steel and ZT do stop pins correctly. Radius cut outs for the impact section of tang to stop pin. I think it's just lazyness for any manufacturer to have a flat surface smacking against a round pin surface, it will always develop a flat spot. I was really surprised to see that even Chris Reeve left this out of his designs. A simple little cutout solves a lot of issues, especially on frame locks where that flat spot has a big effect on the lockup. Chris Reeve could've avoided so much of the "do not flick our knives" fiasco because of the later lockup it was causing if the impact area had that proper radius and the stop pin was at the right hardness.

So you know better than Chris Reeve?

Spey · Oct 31, 2016

Glenn056 said:
Hey everyone lets have a discussion about stop pins: ... What are your thoughts?

My personal thoughts:

...

...

Do share your thoughts about the respective styles!

Sent from my ASUS_Z00AD using Tapatalk

WOW,
The OP asked twice for our thoughts, both early and closing of the OP. Also, did a excellent job sharing his thoughts to get us started.

This thread quickly seems to have gone sideways as folks seem to choose the defensive/offensive cornering technique. Not productive to curious discussion on a public forum :-/

I opened this thread thinking, great subject of discussion.

I come away with one primary thought, you can lead a hose to water, but can not make him drink ...

The concept that removing material from anything makes it inherently weaker seems to be a difficult concept to argue ...

I will however add a little related to what I thought I was getting into when I initially read the subject line.

I "think" based on common sense, AND numerous knives that have crossed my bench, that blade stop designs that offer greater surface contact area (radius vs. flat) can offer better longevity, provided the construction materials & design are up to task.

With regard to traditional stop-pin designs, I have seen a number of knives where aftermarket scales (micarta, G10, etc.) have been installed replacing more structural components (steel liners, metal scale(s), etc. for the appearance sake of a knife. These owners many times are "knife flickers", and the stop-pin holes in the scale(s) rapidly elongate accelerating lock-travel to the point of a knife being prematurely worn out. Properly designed (including application of materials for the intended use/application), conventional internal stop-pins perform well over life-span (my experiences).

In general, I would believe internal (cosmetically hidden) stop-pins are the worst design (for reasons already exemplified by others here, and also because of the potential for hidden contamination), and that in many designs the stop-pin must provide two functions (stopping the blade in the closed position and stopping the blade in the open position AND resisting all forces applied in use. Same goes for bearings in my mind (a trap for contaminants). If a component or design can be made more simply and less expensively, there had better be a good reason to do it differently.

I would be pleased to learn how an internal stop-pin design is better from a function and/or cost of manufacture perspective. I have few reasons; and would like to hear from others that support or prefer these designs.

I believe external stop-pin design utilising thumb-studs as dual-purpose elements to be potentially stronger and potentially better as they provide the greatest potential surface area of contact (depending on scale design and strength). Poor example: unhardened contact areas of a set of Ti scales is gonna require shimming (especially for those habitual knife-flickers), or scales made out of G10, etc.

I believe strongly that each blade-stop design has both function & appearance considerations. When appearance becoming the over-riding design factor is when things fall off the form-follow-function priority that I choose to live by.

Regards,

The Aflac Duck · Oct 31, 2016

Spey said:
The concept that removing material from anything makes it inherently weaker seems to be a difficult concept to argue ...

Not at all, and I agree with it. However, I'm not sure what people are saying it is weaker than and how much weaker? All I see is speculation and no evidence.

Is it weaker and risks breaking during cutting? Batoning? Spinewhacking? Sitting in a safe?

Unless we sit here and test different pivots to their breaking point, I'll stick to the belief that said pivot systems are strong enough for a folder... I guess that's a difficult concept to understand too.