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Tighten lockup of Mercator K55K?


Go Army, Beat Navy!
Oct 6, 2004
Okay, my last attempt on the Old Timer revealed that the spring had simply lost its temper.

On to a new fix. Got a Mercator K55K used off of eBay (first mistake?).

Has the expected wear/patina, but is really light and slim, neat knife.

The blade has no side-play, but a little back-forth play. I cleaned it up and down and all over, but no change.

The spring for the little locking piece seems plenty strong. Are the engaging surfaces simply too worn? Is there any way to build the engagement surfaces back up, maybe smear a little Loc-Tite on them (when not engaged) and let dry? Small smear of solder?

Neat knife though, so now I'm really looking forward to the Douk-Douks I have coming for the THR Group Buy. Mercators are neat but conventional in style. A Douk w/ the scimitar blade and ornate engraving is definitely a cut above.

Loc-Tite or solder won't work. You can remove the backspring and cold forge the lock a little longer.
A new pivot pin will probably help a lot, or possibly even fix it.

Hmmm... all the pins are mushroomed; this critter doesn't look very user-serviceable.

With new ones selling for $20, and my getting some Douk-Douks soon, I might just deal with the ricketyness. I just wanted this one to try out the concept.

It carries really well for such a big knife, it's barely thicker than the blade itself. I understand there were some issues with Chinese clones turning folks of Mercators, but provided you ensure that you're buying a genuine German model, these seem like a great buy.

Of course they are mushroomed. That is how they work. All you have to do is file/grind off the head and drive them out. I would think the pivot pin is the problem.
BTW- springs don't lose their temper if they were properly made. They can be stressed past their elastic limit, ruining them.
I have owned at least a dozen Mercators over the years. I would always find a store with several and hand pick ones with the best lockup. Usually if there is up and down blade play it is because it was not fitted right during manufacturing. I would probably not bother to try and fix it. I would check whether the lock was working reliably. Being careful to keep my fingers out of the way of the edge I would apply some closing force. As I did this I would look at the back lock. I would stop using the knife if the back lock had any creep where it would ride up to try and disengage.