Spyderco backlocks : why is the stop pin an exception, instead of being the norm ?

[Araignee]

I feel like this specific question deserves to be addressed, instead of being drowned amongst various backlock rock discussions, so I made this thread.

Hopefully Sal can chime in and provide more information as to why, the Chaparral for example has been equipped with a stop pin, but not Seki knives like the Delica.

What are the variables at play ? Pricing ? Product positioning ? Manufacturer know-how ?

This is NOT a thread to discuss whether lock rock is a non-issue, or how to define it in the first place.
For these matters, there's that thread : Why do Seki models have lock rock??!!

[Bolster]

The Chaparral stop pin mechanism, photo found on Reddit. Click to enlarge.

[Bolster]

I also found these disassembly photos of the nested liners version, where the stop pin is in a different location on the blade:

[RustyIron]

Yeow. This is my first time seeing something like that. Getting the pin to bottom out at the same time as the lock drops looks like a whole 'nother level of difficulty.

[DavidNM]

I am looking forward to hearing the answer to this question.

[Matus]

I am wonder Whether the motivation was the very thin stock and thus the spring / backlock might be showing too much flex without the stop pin.

[Sharp Guy]

I am looking forward to hearing the answer to this question.

Maybe Sal or Michael will chime in. Otherwise I suspect we won't get an answer to this question

[Sharp Guy]

I am wonder Whether the motivation was the very thin stock and thus the spring / backlock might be showing too much flex without the stop pin.

Sage 4 has the internal stop pin

[Sharp Guy]

I also found these disassembly photos of the nested liners version, where the stop pin is in a different location on the blade:

Here's another....

viewtopic.php?f=2&t=95601&p=1746206&hil ... N#p1746206

[Notsurewhy]

Economics.

What do I win?

[cjk]

similar thread topic:
viewtopic.php?t=60932

quote from Sal in that thread:

Hi Free2game,

Welcome to our forum.

Internal stop pins can offer some advantages in some situations. We don't use them on the Native 5 which hasn't shown any play. the Native lt.wt. will use the same lock geometry as the 5.

Japan doesn't do much with G-10 production. Most of our Seki made G-10 models are using USA made G-10. Usually machined in the US and shipped to Seki.

We've been working with our Japanese makers for more than 30 years. There would have to be a really good reason to move production, especially for our Endura and Delica models. Japanese prices have been going up steadily against the doollar for a number of years. I don't anticipate much change in the future. There is also the possibility of the dollar weakening against the Yen.

As far as steel goes, we have no experience with Acutco so I have no opoinions there. (If anyone here knows anything about Acutco, please share). Nor can I speak for Kershaw or their business model. They are a much larger company than Spyderco and usually have other issues (like supplying Big Boxes) than we do.

sal

[Bolster]

...Getting the pin to bottom out at the same time as the lock drops looks like a whole 'nother level of difficulty.

For a prototype, yes. For production though? Some added complexity, yes, but enough to price it out of reach? Note that the Triad lock has the same issue: the stop pin must hit the blade just as the lock bar drops into its slot. Doesn't seem to stop Cold Steel from cranking them out, though.

CS was fortunate to patent a more cost effective way of engaging a stop pin. They don't have to drill the blade to insert the pin.

If the answer is just economics and only economics, then why on the Chap and Sage 4? Certainly they could have been made without.

[vivi]

...Getting the pin to bottom out at the same time as the lock drops looks like a whole 'nother level of difficulty.

For a prototype, yes. For production though? Some added complexity, yes, but enough to price it out of reach? Note that the Triad lock has the same issue: the stop pin must hit the blade just as the lock bar drops into its slot. Doesn't seem to stop Cold Steel from cranking them out, though.

CS was fortunate to patent a more cost effective way of engaging a stop pin. They don't have to drill the blade to insert the pin.

If the answer is just economics and only economics, then why on the Chap and Sage 4? Certainly they could have been made without.

speaking of the triad lock, here is one for reference



One feature no one talks about is that little hidden pin that serves as a blade stop.

What this means is when the knife is closed, you can squeeze the blade shut while depressing the lock release and it doesn't move.

On just about every lockback / slipjoint style design, the blade will move into the handle.

Why does this matter?

Makes it easier to clean the lock bar where it rubs against the tang without taking the knife apart.

[Bill1170]

...Getting the pin to bottom out at the same time as the lock drops looks like a whole 'nother level of difficulty.

For a prototype, yes. For production though? Some added complexity, yes, but enough to price it out of reach? Note that the Triad lock has the same issue: the stop pin must hit the blade just as the lock bar drops into its slot. Doesn't seem to stop Cold Steel from cranking them out, though.

CS was fortunate to patent a more cost effective way of engaging a stop pin. They don't have to drill the blade to insert the pin.

If the answer is just economics and only economics, then why on the Chap and Sage 4? Certainly they could have been made without.

speaking of the triad lock, here is one for reference



One feature no one talks about is that little hidden pin that serves as a blade stop.

What this means is when the knife is closed, you can squeeze the blade shut while depressing the lock release and it doesn't move.

On just about every lockback / slipjoint style design, the blade will move into the handle.

Why does this matter?

Makes it easier to clean the lock bar where it rubs against the tang with taking the knife apart.

In that last sentence, did you intend to type, “…without taking the knife apart.”?

[vivi]

yep, lol.

[sal]

Hi Araignee,

It's a realistic question and some of the reasons have already been discussed above. Our Taichung maker began making back-locks with stop pins from the beginning. A relatively small maker with a get deal of Engineering and manufacturing skill. We tested them with a few simpler to manufacture, locks, before we made Back-locks with them.

In Golden, we took another approach. We just kept refining the engineering to be able to bring that tolerance to a very high level without the extra parts. The Japanese have been making lock-backs for long time and they too , have been refining.

Early Chinese back-lock were a challenge. All are improving.

I think that Golden, as well as our outside makers are all extending their best effort to serve you.

Making locks for knives as sharp as ours is something we take very seriously. And we're always thinking about improvement. Improving even a small change is more complicated than it might appear to fit into production.

I hope that answers your question?

sal

[Wartstein]

......

This is NOT a thread to discuss whether lock rock is a non-issue, or how to define it in the first place.
For these matters, there's that thread : Why do Seki models have lock rock??!!

This is NOT meant as "discussing wether lock rock is a non issue" - but my personal reply to the question just IS:

While in all of my backlock Spydies except the Chap I can induce some up and down play if I try really hard (by pressing the blade on a surface with a lot of force for example), most times it is just so slight that it does not matter or can not even be perceived in normal knife use - and if, it does not matter functionally, so that most regular knife users probably really don´t care.

So it is probably just not worth it to take the effort, higher complexity and costs that would be necessary to change all backlock Spydies to a stop pin design...

That said: While I don´t mind the slight play some of my Seki knives might have, the rock solid lock up of my Chap sure is pretty cool. Functionally not necessary though (to me).

[Ngati Pom]

Could it be that the stop pin is harder to retrofit on existing models?
It appears on ‘newer’ models, Chappy and Sage 4, but may be beyond the scope of CQI.
If and when the Delica/Endura range gets an update maybe it will include the stop pin.
And a choil!

[PaloArt]

Could it be that the stop pin is harder to retrofit on existing models?
It appears on ‘newer’ models, Chappy and Sage 4, but may be beyond the scope of CQI.
If and when the Delica/Endura range gets an update maybe it will include the stop pin.
And a choil!

I wholeheartedly agree with the last sentence! If there would be, in following years, new generation of Seki backlocks, it would make prhaps sence to have this solution incorporated and it would make sense to wait until then as well. Right now any heavy updates like this on the current production would mean as well to create new FRN casting molds I guess and I think that is very very expensive. I will not lie, I would like to see Seki pieces either Chaparral\Sage Back Lock stop pins or some magical solution like on Delica Gen 2 and 3 or Salt series gen 1 where the lock is extremely secure without any blade play (my Pacific Salt 1 is rock solid and really abused knife).

[Michael Janich]

Hey, All:

Great question and cool discussion.

Having designed a couple of knives with internal stop pins, I think it's important to remember a few things. First, stop pins that ride in arcuate slots can provide one or both of two functions--limiting the travel of the blade in the open and/or closed positions. In the open position, they are typically an element of the lock "triangle." In the closed position, they function like a "kick" to prevent the edge from contacting the inside of the handle.

An internal stop pin also requires metal liners--especially if it is a functional element of the lock triangle. Linerless knives with G-10 scales (like the Native 5 and Native Chief) or FRN scales (Like the Native 5 Lightweight, Native Chief Lightweight, Stretch 2 XL, etc.) can't use internal stop pins without adding at least partial liners.

Finally, arcuate slots take up a lot of space, so they require knife designs with fairly broad handles and blade ricassos. The shape of the Chaparral does that well; the Delica and Endura, not so much.

Food for thought...

Stay safe,

Mike