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Umnumzaan O-Rings

sailfish

Basic Member
Joined
Jan 1, 2019
Messages
857
I was curious if the o-rings on the Umnumzaan were just for sound dampening or if they were essential to the lockup of the knife.
 

guy g

Platinum Member
Joined
Oct 22, 2000
Messages
2,035
I don't remember the full story, but they are a cushion at the blade stop. I think if they are missing the blade won't set properly.
 

Ajack60

Platinum Member
Joined
Apr 21, 2013
Messages
6,946
Both, you can do away with the o rings and not have any issues. However, it will cause later lock up and I don’t know if that would result in lock stick. I know it’s time to change them when I hear an audible click upon lock up. You can rotate the flat spot, but it won’t take long for them to flatten again.
 

krazichinaman

Pew Pew Pew!
Moderator
Joined
Jul 8, 2001
Messages
1,544
Hi Sailfish,
The O-rings have a few functions as others have mentioned, but are not essential to the lockup of the knife.

You can reference the official CRK Youtube video "How To Clean Your Umnumzaan" where Tim talks about it @ 6:09



Hope this helps!

PS - I'm still trying to find one available for myself....so I can't wait to get my own. Enjoy yours for me in the meantime!

Regards,
Brian
 

sailfish

Basic Member
Joined
Jan 1, 2019
Messages
857
I've always found them intriguing but that o-ring was always the biggest thing holding me back. If they're not a critical part of the lockup that's great, and the fact that they're a standard size is even better. I'll have to give the Zaan some more consideration in case I see an S45 one come along.
 

sailfish

Basic Member
Joined
Jan 1, 2019
Messages
857
Tantos are the first versions to come out in s45vn and a few have already hit retail...I may have to fight you for the s45vn DP version when it hits the shelf...HAH!

Good luck on your hunt!
You're in luck there. My sights are on the tanto.
 

nyefmaker

Gold Member
Joined
Sep 29, 2008
Messages
6,167
I heard a podcast with Chris where he said it has no function except dampening the sound. Lock works fine without it but this was years ago.

This was stated by Chris Reeve himself when the zaan was introduced.
 

zyhano

Gold Member
Joined
Dec 3, 2009
Messages
1,554
recently ordered some new o-rings, but I have rocked the zaan for years without them, with a very solid lockup. they are not needed perse :)
 

BD_01

Basic Member
Joined
Jun 9, 2016
Messages
3,065
Material - Viton® Fluoroelastomer Rubber.
Width - 1/16"
ID - 1/8"
OD - 1/4"

Actual
Width - 0.07"
ID - 0.114"
OD - 0.254"

AS-568 (size)# is -006

I prefer the hardware store variety (Buna-N) over the CR polyurethane variety, even though they wear out more quickly. The *thug* they make is more gratifying and they’re cheap & easy to replace.

I want to try Viton, but last I checked I’d have to order them in bulk. :-(


Does anyone have a pic of one next to a small Sebenza?

sailfish sailfish

 
Last edited:

"Havoc"

Gold Member
Joined
Mar 20, 2016
Messages
350
Umnumzaan Tanto is where it’s at ;)

I was lucky enough to score an Umnumzaan Tanto S45VN from Ye Ole Cutlery. Now I just have to play the waiting game for it to arrive with all the bad weather running through that side of the country.

I use Buna-N Nitrile and really love them. They last a long time and hold up to oil and chemicals.
if you get them, pick up the 70 Duro O-ring. Looks small but fit perfect, snug so it won’t come off and same size once installed as the CRK ones. I dislike the CRK o-rings because they turn to mush really quick...in matter of months.

I prefer the o-rings being installed myself. I like the sound it makes!

7E5FBE17-73C2-490A-82F2-2536E5F65DC7.jpeg
 
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