Benchmade 830 spine whack failure

Oct 5, 1998
I have a BM 830 Eclipse (2years old) (now called the Ascent) which is a lock back knife - great was my amazement when I did the "spine whack test" 20 times and the lock failed 20 times. Has anyone else had the problem. The failure was totally unexpected because of the fact that I "trust" lockbacks totally - just goes to show!

Did you check to see if the lock notch was clean? Generally, I've found lock back failure to be due to a clogged notch. I am sure it can also be the result of wear. I think lockbacks seem more reliable than linerlocks, some of which fail brand new, right of the box.

David, this knife has hardly been used and is clean. So it can't be wear. I will take it apart and try to figure out what is wrong.
Deon, Mike Turber reported similar things with the 840 model awhile ago :

You might want to ask on Benchmades forum although the last time the official word was basically "don't do that". This is of course not sensible as since there are lockbacks that can take impacts and remain stable, what is the advantage of making one that can't?

Hi Deon,

I'm curious to learn what you find to be the cause of the lock failure. Mike Turber did some spine whack tests on a number of knives a few months ago and one of the models that failed was the BM 840. Once I read his results, I tested my BM 830 Eclipse (also about 2 years old) and it held up just fine.

As I recall, I number of other folks reported similar problems with their 840s but I don't remember any reports of 830 or 820 lock failures. It's a shame the search function is down, but if you browse the posts from the Feb-Apr period you may find some info that will be of value in determining the cause of your problem.

Oops -- Cliff beat me to the punch.



[This message has been edited by bcaffrey (edited 12 July 1999).]
For all practical purposes, the Eclipse series was BM's first entrance into the realm of mid-lock, lockback folders comparable to the mechanism used on Spydercos and Al Mars (the originator of the mid-lock if I'm not mistaken). The original design was intended to enable a rockerbar-lockback to be easily closed with one hand, while still retaining the strength of the lockback design.
What's likely going on with the failures you're experiencing is that in BM's efforts to enter into this foray (though it is not their first lockback, but indeed their first mid-lock), they messed up in one of two ways if not both. Either the blade tang channel or the rocker bar hook is too shallow for effective locking under stress, or the spring exerting pressure on the rocker bar is too weak and is buckling under the stress of the spine whacks. More than likely it is the combination of the two elements that are causing your heartache. My suggestion is to cut your losses, treat your knife as if it's a slip joint, and get yourself either a mini or full sized AFCK with an ultimately more reliable lock and superior features in general. Then there's the axis... don't give up on BM because of one dud. I really think they've got the best knife for the money.


Ever notice no other candy tastes quite like Pez? Oh yeah, and the BM Axis rules.

I own a 840 and a 845, and both are very very strong. Both were purchased less than two months ago and I feel they are stronger than my Voyagers ... these babies realy lock up !!

Maybe I was just lucky or the new ones are better made, I don't know, but I'm very happy with mine.

My 820 fails the spine whack test every time.

I cleaned it meticulously after the first failure with no improvement in performance.

It has been added to the bag of cheap resale/trade knives.

Just did about 25 spine whacks on my BM Eclipse (the orginal 830, which is now the Ascent, right). It is that old, 3 or 4 years. Anyway, passed all of them. Beat it on the spine of a book, and the hard edge of a chair. No failures. Whew!

Work hard, play hard, live long.