Umnumzaan lockbar modification - explodes tension?

[UrFrndlyNebrhoodS]

Hey ya'll,





I have owned nearly 3 Umnumzaans in my humble CRK knife collection history and like many others, regret having sold or traded them at one point or another. The original design without the L.B.S. system appeals to me most but alas are getting harder and harder to find. On the plus side, there seemed to be a slight redesign of the later model Umnums which IMHO makes the knife all the more ergonomic. However, the new redesign also makes the thumbnail tab on the lockbar much bigger and even sharper. For me in the past it has created such a hotspot as to force me to inevitably sell it.

The Umnumzaan is such a cool knife though, so my question is....Will any modification to the lockbar face change the tension of it and if so, by how much? If one were to grind off that tab say and apply a smoother surface, would it totally mess up the beautiful lockup that the Umnumzaan exhibits? I'm not so much concerned about voiding the warranty as disabling the knife from its near perfection. Thanks

 

[hondahirny]

Was the lockbar sticky? The overall tension is a function of the lockbar length (leverage) and thickness. Only way to reduce tension is to remove more Ti near it's "hinge" area. This would be a warranty voiding exercise and best done on a mill.

The lockbar face would only affect any lockbar sticking. Newer Umnum's use a ceramic ball for the lockbar face anyhow.

Ultimately, if you have to do that much to be happy with a $400 knife, perhaps pick something else?

 

[TTTis]

Grinding the tab down used to disengage the lockbar shouldn't be a problem. It shouldn't have any effect on lockup. As long as we are thinking about the same thing. I've never owned an Umnum, but I can imagine in a white knuckle grip that area could dig into the fingers.

So you just want to grind down the tab to even it off with the other scale right?

I don't think it is unreasonable to modify a $400 knife to suit you best. There are no other knives like them on the planet and if you gotta have one... make it your own. Just understand the warranty is likely gone, for some of us it's worth the risk. Mod on my friend, but be sure to post pictures when done.

 

[Blades'n'45]

I know what your talking about with the re design of the tab on the umnum making it a hot spot when you disengage the lock.
I never had a problem dis engaging the earlier umnums with the smaller tab and it was a lot more comfortable to do so.
It probably also depends on how much tension the lock bar has and how much force is needed to push it over coupled with the
sharper tab. So you can probably make it easier to disengage by loosening the tension on the lock bar but you would have to take
it apart and bend the lock bar out and risk messing up whole lock bar.
Plus I don't think you can even do that on the newer umnums with the lock bar stop, So grinding down the tab is prob your only solution.

 

[UrFrndlyNebrhoodS]

Thanks, all for the thoughtful advice. Yeah I really have no intention in altering the lockbar in any way as far as the tension goes. In the few ones I did own, all of the Umnumzaans had non-sticky locks. Granted they were stiff at first but after a break in period, the stiffness was appreciated. It is correct to say I would like to grind down only the tab to round off and not even that it has to necessarily be even with the front scale. I rarely ever use gloves with a folder so not really concerned with loosing some traction when one-handed closing the knife.

I haven't found another knife out there when it comes to the Umnumzaan when all things are considered. So price aside, if the modification doesn't ruin the action, then it would be worth the outcome however attractive or ugly it may be.

 

[Blades'n'45]

Or you can always try to find an older umnum. I handled an older S30V model before any changes were made (solid washers, no Idaho, etc) and I swear it was the smoothest
knife I've ever handled. Plus the lock bar was so easy to disengage but still locked up like a bank vault. Should have kept that one.