What is the point of this notch?

Discuss Spyderco's products and history.
jalcon
Member
Posts: 945
Joined: Wed Sep 04, 2013 8:50 am
Location: Hershey, PA

What is the point of this notch?

#1

Post by jalcon »

What is the purpose of this cutout in the PM2 tang? Where the red arrow is....(this is not my knife btw)

Image

Because mine looks like this and isn't a nice straight clean edge. Will this effect anything?

Image

Right now it doesn't seem like it does. Just making sure. Yes this goes along with another thread I had.

Thanks!
User avatar
Evil D
Member
Posts: 27147
Joined: Sat Jun 26, 2010 9:48 pm
Location: Northern KY

Re: What is the point of this notch?

#2

Post by Evil D »

I'm thinking that's the ramp for the detent ball?
All SE all the time since 2017
~David
jalcon
Member
Posts: 945
Joined: Wed Sep 04, 2013 8:50 am
Location: Hershey, PA

Re: What is the point of this notch?

#3

Post by jalcon »

Evil D wrote:
Thu Jan 19, 2023 5:34 pm
I'm thinking that's the ramp for the detent ball?
Yeah I have no idea
zhyla
Member
Posts: 2216
Joined: Tue Apr 20, 2010 2:12 pm

Re: What is the point of this notch?

#4

Post by zhyla »

Evil D wrote:
Thu Jan 19, 2023 5:34 pm
I'm thinking that's the ramp for the detent ball?
It’s at the wrong distance from center isn’t it?

Are they cutting these with EDM? It looked to me like maybe a hole for the EDM wire.
marrenmiller
Member
Posts: 4
Joined: Tue Jul 24, 2018 10:06 am

Re: What is the point of this notch?

#5

Post by marrenmiller »

Looks like it's a fillet to eliminate the stress concentration that would otherwise be present there.
User avatar
Evil D
Member
Posts: 27147
Joined: Sat Jun 26, 2010 9:48 pm
Location: Northern KY

Re: What is the point of this notch?

#6

Post by Evil D »

zhyla wrote:
Thu Jan 19, 2023 10:04 pm
Evil D wrote:
Thu Jan 19, 2023 5:34 pm
I'm thinking that's the ramp for the detent ball?
It’s at the wrong distance from center isn’t it?

Are they cutting these with EDM? It looked to me like maybe a hole for the EDM wire.



Hard to tell, I can't really make out where the detent path is, it looks like it wouldn't be centered with the detent hole and it looks a little small but I'm not sure what else it could be, It could be a random leftover related to laser cutting. I've made similar ramps myself on several compression lock and liner lock knives.
All SE all the time since 2017
~David
JD Spydo
Member
Posts: 23555
Joined: Tue Sep 28, 2004 7:53 pm
Location: Blue Springs, Missouri

Re: What is the point of this notch?

#7

Post by JD Spydo »

I'm clueless at this point concerning that notch. Because I rarely ever take apart any of my Spyderco blades. However I do like the USA made Spyders that are most easy to take apart if I would ever find a need to do that. I've just had so many Spyderco models over the years and I've been fortunate that I haven't really experienced any significant failures. For instance I've never had any of Spyderco's locking systems ever fail on me. Regardless of which type of locking system it is.

I tend to go with the old philosophy "If It Ain't Broke Then Please Don't Try To Fix It">> that philosophy has worked for me all my life.
User avatar
hereiamu1
Member
Posts: 283
Joined: Tue Jun 26, 2018 6:45 pm
Location: WA

Re: What is the point of this notch?

#8

Post by hereiamu1 »

jhvjhvhj.jpg
If the blade lockup is good I wouldn't mess with it.
James Y
Member
Posts: 8078
Joined: Fri Sep 24, 2004 10:33 am
Location: Southern CA

Re: What is the point of this notch?

#9

Post by James Y »

I'm no expert, so take this with a grain of salt. Could it possibly be part of the design to absorb or reduce stress along that radius?

Jim
jalcon
Member
Posts: 945
Joined: Wed Sep 04, 2013 8:50 am
Location: Hershey, PA

Re: What is the point of this notch?

#10

Post by jalcon »

hereiamu1 wrote:
jhvjhvhj.jpg
If the blade lockup is good I wouldn't mess with it.

Yes I know it's not "normal". I made a thread on this a few days ago...just trying to figure out what the notch is for...
James Y wrote: I'm no expert, so take this with a grain of salt. Could it possibly be part of the design to absorb or reduce stress along that radius?

Jim
Could be. Maybe Sal could chime in?
User avatar
Guts
Member
Posts: 360
Joined: Wed Sep 07, 2022 8:53 am
Location: Pacific Northwest

Re: What is the point of this notch?

#11

Post by Guts »

Took a look at a few of my compression lock models (PM2, Para3, Yojimbo2, and Lil Native) and they all have that relief cut. I agree with others that it's likely for stress relief as the flat surface above that cutout is one half of where the compression lock is compressed between. The other half being the stop pin.
:bug-red-white :bug-red :bug-white-red
User avatar
RustyIron
Member
Posts: 2406
Joined: Mon Mar 18, 2019 9:01 pm
Location: La Habra, CA
Contact:

Re: What is the point of this notch?

#12

Post by RustyIron »


I suspect the flat surface is finished separately, toward the end of assembly, to create a perfect lockup. Reliving the area behind the lock surface allows easier final finishing.

User avatar
shunsui
Member
Posts: 1647
Joined: Fri Apr 12, 2013 10:22 pm

Re: What is the point of this notch?

#13

Post by shunsui »

zhyla wrote:
Thu Jan 19, 2023 10:04 pm
Are they cutting these with EDM? It looked to me like maybe a hole for the EDM wire.
I recall a similar question years ago and it was the starting point for the cutter. I'd guess that's what it is.
User avatar
Dodge
Member
Posts: 1132
Joined: Mon May 16, 2005 5:12 pm
Location: Virginia, USA, Earth

Re: What is the point of this notch?

#14

Post by Dodge »

I believe it’s a channel for debris to accumulate instead of effecting the lockup. It’s not a defect, all 4 of my paramilitaries have this.
Last edited by Dodge on Sat Jan 21, 2023 6:44 pm, edited 1 time in total.
Flash Batch request: Flat Iron Salt (CE w/ yellow FRN)
New knife request: Police 4 Salt!!!

“Don’t be so open minded that your brain falls out”
Wandering_About
Member
Posts: 1391
Joined: Thu Mar 25, 2021 10:06 am
Location: Earth probably?

Re: What is the point of this notch?

#15

Post by Wandering_About »

It's a channel for collecting the power from dark matter to increase edge retention.
Because desolate places allow us to breathe. And most people don't even know they're out of breath.

MNOSD member #0035
jalcon
Member
Posts: 945
Joined: Wed Sep 04, 2013 8:50 am
Location: Hershey, PA

Re: What is the point of this notch?

#16

Post by jalcon »

Dodge wrote:
Sat Jan 21, 2023 5:50 pm
I believe it’s a channel for debris to accumulate instead of effecting the lockup. It’s not a defect, all 4 of my paramilitaries have this.
Of course they all have it haha, I'm questioning mine...which looks nothing like other PM2s, the bottom is real rough looking. Was wondering it mattered, that's all.

Image
User avatar
Dodge
Member
Posts: 1132
Joined: Mon May 16, 2005 5:12 pm
Location: Virginia, USA, Earth

Re: What is the point of this notch?

#17

Post by Dodge »

jalcon wrote:
Sun Jan 22, 2023 12:09 am
Dodge wrote:
Sat Jan 21, 2023 5:50 pm
I believe it’s a channel for debris to accumulate instead of effecting the lockup. It’s not a defect, all 4 of my paramilitaries have this.
Of course they all have it haha, I'm questioning mine...which looks nothing like other PM2s, the bottom is real rough looking. Was wondering it mattered, that's all.

Image
Technically speaking yours has more mass and is structurally more sound!! It it bothers you I’m sure you could take a razor blade and knock off the burr.
Flash Batch request: Flat Iron Salt (CE w/ yellow FRN)
New knife request: Police 4 Salt!!!

“Don’t be so open minded that your brain falls out”
Post Reply