Kershaw Tac-Bump: what lock does it has?

D

DavidW3

Joined
Dec 20, 2003
Messages
69
Hi guys:

I was able to check out a tac-bump at a local shop today. I noticed that its locking mechanism is quite interesting. I could see it uses a little piece of spring pushing against something like a thumb stub on the blade itself. Any more details I wasn't able to see from the look of it. Perhaps I'm not used to that kind of lock yet and so there was a few times I found it hard to unlock the blade to close the knife. And I didn't want to jiggle it too hard in fear of the blade closing itself on my hand. I also wonder how long that piece of spring will last cuz' it doesn't look like it's very strong to me. I suspect if that piece of spring loses its strength, the lock will go, too. Any of those who own this knife could comment on it?
 
You mean the Spec Bump?

You are right that it is a spring pushing on the thumb stud. It is called a Stud Lock.

The thumb stud is pushed into a recess on the handle to prevent the blade from closing. To close the blade, you push the thumb stud out of the recess and then continue around into the closed position.
 
Yes, the knife will not lockup minus a spring. But this is true of virtually every lock system. The ones that think far ahead have spring redundancy. The stud lock has some interesting spring advantages....it's always at its resting state, never compressed, either open or closed. It only gets compressed very briefly on its ride to the locking position and then being unlocked. I don't know much about springs, but I'd imagine that would be positive.

I own one stud lock and it treats me well. One obvious advantage of the system is that lefties are not overlooked with this lock mechanism. Other parts of these knives, maybe, however.

I've used a spec bump before (and as soon as NGK gets the new one in, I might own one) and loved it. I chose the original Blue Bump over it the first time around though. Pick it up, I think you'll enjoy it.
 
I've been using mine dailey for over a month now. I've not had any trouble with the stud lock. I find it to be about the best lock mechanisim going, perhaps in a tie with the axis lock on some benchmades. I've mastered the one hand operation, and my thumb now seeks the stud, rather than the liner :-)

No complaints on this knife. Get one.
 
Artfully Martial said:
Yes, the knife will not lockup minus a spring. But this is true of virtually every lock system. The ones that think far ahead have spring redundancy. The stud lock has some interesting spring advantages....it's always at its resting state, never compressed, either open or closed. It only gets compressed very briefly on its ride to the locking position and then being unlocked. I don't know much about springs, but I'd imagine that would be positive.
Click to expand...
You would think, but talking to engineers about springs (specifically about the springs in pistol magazines from WWII), it seems that keeping a spring compressed normally is no problem. The problem occurs when you compress a spring further than it is designed to be compressed.

Kinda off topic, but FYI...
 
My only complaint about this knife is that dirt can get into the spring area of the blade and cause it to be difficult to unkock. It is fun showing it to people and seeing them not be able to close it because they can't figure the mechanism out.

Brian
 
That could be any lock though. Maybe our new spine whack test should be handing an open knife to John Q Public and watching him try and force the blade closed, study it, try and force it again.

My favorite was a guy who was taking a glance at my d2 minigrip. He opened it and gave me a disapproving look. Apparently he thought locking knives were supposed to lock CLOSED not open. So he ended up thinking my Benchmade was a cheapo knife.
 
I hadn't noticed the sensitivity to grime on any other lock type in my collection. Mine got stuck on a piece of cheddar cheese and would not close. I'm not too impressed with the method of one hand closing either. The other knife I had problems one hand closing was a Spydy with the back of the blade frame lock. I've forgotten the name. :grumpy: Senility is rearing it's ugly head. And of course my Kershaw E.T. is a great little excuse to invest in band aids. Almost everyone I know who has one has cut himself at least twice. Their just so much fun to play with.:D

Brian
 
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