Chris Reeves Lock Pin Mod

bermo

bermo

Gold Member
Joined
Dec 3, 2021
Messages
393
Got an older (35vn) Large Inkosi that has had an issue with its lock up since I acquired it used, it would disengage by hand when locked.

Sent I sent it back to CRK and they said they fixed the issue, which they did, but now the lock bar almost bottoms out against the show side scale. I went back and forth with them via email talking about how it feels and seems it will bottom out against the scale soon, and that it does not feel, or look like my other CRK's. So I spent another $10 shipping it there and another $25 shipping it back, along with new backspacer and screw for whatever reason. $60 later nothing changed.

PXL_20241230_161828874.jpg

So, I got to thinking, what if I made a larger lock pin to prevent the blade from engaging too far?

The OEM pin measures .2495 going into an .250+ hole in the scale, the threaded side was .1865 going into a .187+ hole. I had to make the middle bigger where the blade hits, while maintaining the ends that fit into the scales.

I tried a .010 shim in between the pin and the blade to get an idea of where to start, and it seemed a bit much, so the first pin was at .263 (almost .007 per side bigger).

PXL_20241231_212347598.jpg

Too big, as I could close it by hand.

Went down to .260 and it was better, but I could still close it by hand, just had to try super hard.

Then on my third attempt I went to .257. Perfect. Looks like my other CRK's and it's a solid lock up.

PXL_20241231_220406470.jpg

Here is the OEM pin next to mine.

PXL_20241230_193702500.jpg

Something I found interesting was the thread pitch. I was having a bit of a trouble figuring out the threaded hole and I couldn't find any info online. It is super duper close to a 4-40, and I really thought it was a 4-40, but it was not. So maybe a 4-32? Nope. It definitely was not an 8-40 etc.

Turns out to be a M3.5 x 0.6 metric thread. The 5/64" hex head is really a 2mm.

-JB
 
WAY TO GO !
I am super impressed !
Sounds like some of the rigamarole I went through with my beloved Benchmade 710 (blue and black G10 M390 blade) but not the lock up.
Had to fix it myself / make a part in the end but zero willingness from BM even after I knew what I needed to fix it and asked them to send me the part and name their price.

I often say : To make it in this modern world one needs a lathe, a TIG welder and a Swiss Army knife . . . otherwise heaven help you.

Thanks for posting this most interesting and educational fix and
HAPPY NEW YEAR !
 
I am super lucky to have access to Lathes / Mills / Grinders / etc.

Forgot to add, the material for the pin is O-1 drill rod. Got that little bitty bitty pin dang near white hot then quenched it in some oil. Didn't do a Rockwell on it but it passed the file test.

Happy New Year Blade Forums!
 
Wow, awesome job man! I think people very often forget about the stop pin when they're having issues with lockup. The stop pin is so important. I have one knife, a very old titanium framelock CRKT S2 that the lockbar was all the way up against the opposite scale causing a tiny bit of bladeplay. I unfortunately don't have access to a lathe, however I got lucky because the stop pin and the lower standoff are the same size. I switched their positions and it gave me a little more life left in it, it turned out to be a very slightly larger diameter for whatever reason.

Anyway, very nice!
 
It doesn't take much, like .003 was making it work or not.

100% agree that the stop pin has a huge affect on performance.

If someone has an older, heavy use knife they could try and rotate the lock pin to see if anything changes.
 
Yeah I've done that too, with rotating it. Wow, yeah just .003 made all the difference. I have an old Benchmade auto that has a hexagonal (or some such shape) stop pin, kind of interesting. I'm kind of wondering if Benchmade machined the pin so that the tolerances are slightly different depending on which side of the hexagonal stop pin the blade tang contacts. Probably wishful thinking and it's symmetric. Anyways, just kind of kickin the tires.
V2hzGKy.jpg
 
I bet the angle of the grind where the lock bar hits determines how much pin diameter affects the lock up.

It's definitely a fit to size kinda thing.
 
rycen said:
It’s called an eccentric stop pin
Click to expand...
Ok cool thanks. It's funny, I wanted to call it that because of Spyderco's Eccentric pivot that they used to have, but wasn't sure. Do you know if the lockup will change then if I turn the stop pin so that the blade tang is hitting a different flat? Thanks.

Sorry bermo bermo , I feel like I'm kinda commandeering your post on accident. I'll fade out after this question. Cheers! 🍻
 
OP, nice fix and too bad CRK was not more helpful. You are fortunate to have access to the tools you have!
 
LimpCroissant said:
Ok cool thanks. It's funny, I wanted to call it that because of Spyderco's Eccentric pivot that they used to have, but wasn't sure. Do you know if the lockup will change then if I turn the stop pin so that the blade tang is hitting a different flat? Thanks.

Sorry bermo bermo , I feel like I'm kinda commandeering your post on accident. I'll fade out after this question. Cheers! 🍻
Click to expand...
Yes, the lock up will change when you rotate the stop pin. Great feature to adjust for wear, of both the stop pin and the lock bar.
 
Great job, very impressive work and dedication! This solidifies my dislike for frame locks. If only CRK would make a lock back.

Sorry, I'll let myself out.
 
Guys
just for the "Record" the average plus/minus for CNC stuff is +/- 3-5 thou... so each of the hundreds of parts they have made for them have this type of variation...
i looked into buying some parts years ago ,and that was the "normal" range i had to be willing to live with....
if you want exact size parts the price Triples.... no dog in this ,just wanted to make sure people know CRK/Whoever does not make the parts they use.... they commission a shop to build them for them
 
Pinoy Knife said:
Guys
just for the "Record" the average plus/minus for CNC stuff is +/- 3-5 thou... so each of the hundreds of parts they have made for them have this type of variation...
i looked into buying some parts years ago ,and that was the "normal" range i had to be willing to live with....
if you want exact size parts the price Triples.... no dog in this ,just wanted to make sure people know CRK/Whoever does not make the parts they use.... they commission a shop to build them for them
Click to expand...
A recent video from Tim Reeves states that CRK now makes their own fasteners to make sure they get the quality/hardness they expect. If you search around I think it was before the recent blade show.
 
bermo said:
Got an older (35vn) Large Inkosi that has had an issue with its lock up since I acquired it used, it would disengage by hand when locked.

Sent I sent it back to CRK and they said they fixed the issue, which they did, but now the lock bar almost bottoms out against the show side scale. I went back and forth with them via email talking about how it feels and seems it will bottom out against the scale soon, and that it does not feel, or look like my other CRK's. So I spent another $10 shipping it there and another $25 shipping it back, along with new backspacer and screw for whatever reason. $60 later nothing changed.

View attachment 2748229

So, I got to thinking, what if I made a larger lock pin to prevent the blade from engaging too far?

The OEM pin measures .2495 going into an .250+ hole in the scale, the threaded side was .1865 going into a .187+ hole. I had to make the middle bigger where the blade hits, while maintaining the ends that fit into the scales.

I tried a .010 shim in between the pin and the blade to get an idea of where to start, and it seemed a bit much, so the first pin was at .263 (almost .007 per side bigger).

View attachment 2748228

Too big, as I could close it by hand.

Went down to .260 and it was better, but I could still close it by hand, just had to try super hard.

Then on my third attempt I went to .257. Perfect. Looks like my other CRK's and it's a solid lock up.

View attachment 2748236

Here is the OEM pin next to mine.

View attachment 2748237

Something I found interesting was the thread pitch. I was having a bit of a trouble figuring out the threaded hole and I couldn't find any info online. It is super duper close to a 4-40, and I really thought it was a 4-40, but it was not. So maybe a 4-32? Nope. It definitely was not an 8-40 etc.

Turns out to be a M3.5 x 0.6 metric thread. The 5/64" hex head is really a 2mm.

-JB
Click to expand...
CRK got famous by doing this stuff, before shipping. It was a long long time ago, but Sebenza=tight tolerance machining, was why they were more expensive too, I'm told.
 
jjg6319 said:
OP, nice fix and too bad CRK was not more helpful. You are fortunate to have access to the tools you have!
Click to expand...
To be honest I was a little turned that they didn't do anything but charge me for a backspacer and screw that I didn't really need, especially for a $450 knife.

If they would have come back with "The grind where the lockbar hits is worn and you need a blade", I would have been good with it, but they just relaced some hardware unnecessarily and sent it off.

But I'm over it, gonna continue to use CRK's till the end of time. Still one of my favorites.


FWIW, here is the blade where the carbide ball hits.

PXL_20241230_162343772.jpg
 
bermo said:
To be honest I was a little turned that they didn't do anything but charge me for a backspacer and screw that I didn't really need, especially for a $450 knife.

If they would have come back with "The grind where the lockbar hits is worn and you need a blade", I would have been good with it, but they just relaced some hardware unnecessarily and sent it off.

But I'm over it, gonna continue to use CRK's till the end of time. Still one of my favorites.


FWIW, here is the blade where the carbide ball hits.

View attachment 2753241
Click to expand...
I thought they would have cut you some slack on a Magnacut blade if you wanted to go that route.
 
It sucks that CRK didn’t fix it but congratulations on fixing it yourself with a new stop pin. Well done!!!
 
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