My 2 cents on the subject:
I would always go for reputable retailer as it was suggested in the thread but sometimes retailers as Amazon and Sleazbay offer better price and this could be a factor.
If you ask here or have little experience how to buy from such places you can get a really good deal for less. I snatched my Caly 3 for almost $60 cheaper form A-zon, compared to the cheapest prices everywhere else and the knife came in impeccable condition...
I'm curious if you paid $20-$30 less with A-zon than the average price those ZT goes ? Sometimes they sell knives with damaged boxes or small imperfections, usually on the packaging, from handling those in the warehouses and it's listed in the descriptions,
but it is buried in some other verbiage so if you complain later they can always point to it... One have to be really careful if goes for such deals, the other option is to pay the average price and have the sort off "insurance" that the retailer will sell you a product in good condition or will make it right if for some reason the knife have something that you don't think should be there.
In regard of the detent, my 620cf which is essentially the same knife but with different blade style, have 3600+ serial number, black screw and small hole. Right out of the box it was one of the smoothest opening folders I ever had.
This applys to when you flip the blade with your thumb ( and I don't usually do wrist action). If you ride the thumbdisk, as I'm used to, and if you are used to holding a liner lock, you basically applying pressure over the lock bar, making really hard for the ball to un-lock. The more you are pushing on the thumbdisk, the stiffer the lock becomes. I'm wondering if this is the case, I just can't imagine a new ZT knife came with such a stiff detent that you'll hurt your finger.
I learned to ride the thumbdisk on the 620 by supporting the other site with my index finger placed over the area where the hex head of the pivot is recessed, it opens just as a liner lock.
The blade should ride on a washers that are not really polished and this could make it little bit tighter, I seriously doubt this is the case but maybe worth mentioning it. I usually run those few times on a piece of used 2000 grit sanding paper, only to clean the micro burrs they have, that's it. It's a production knife after all, I usually don't pay attention to such things but some people do, nothing wrong with this.
Honestly I'm surprised to hear so many users mentioning the stiff detent on those, everyone I know praises ZT for buttery smooth opening. I also like little bit stiffer detent and opening, actually I had to slightly tight the nut on my ZT after few days of opening it, seemed too lose to my taste...
I did not pay a cheaper price on Amazon when compared to other retailers. The 0630 costed me $200 which is the same price as everywhere else, so I only saved money because I had some Amazon gift cards.
I can ride the blade on the black screw 0630 no problem and it is super smooth (it opens just like any Emerson linerlock), but the silver screw is impossible with this method. Just the slightest amount of pressure on the lockbar will cause the blade to be held by the detent. The only way to open the silver screw 0630 is with a thumb flip and wrist flick, but the thumb disk removes some of your fingernail when doing so. So far I have found that flicking the blade out with the index finger is a little better. This is my first knife with such a stiff detent where any pressure on the lockbar will cause a problem. I also have two other framelocks which are a XM-18 3.5 Flipper Gen 3 and a large Sebenza, and both of these knives don't care if you have some pressure on the lockbar. They still open if your index finger rests on the lockbar. I really do hope the detent on the 0630 gets better because it would be silly to have such a strong detent on a tactical knife. In a self-defense/life-threatening situation, if the wave method fails to catch on your pants then the only other way to open it is with the thumb disk. The problem is that when adrenaline is flowing in a stressful situation, one is likely to grip the knife even harder and will not have the time or luxury to find proper hand placement to open the knife quickly. I really love the ergonomics, blade shape, and heavy feel of this knife.. but if the detent does not get better then I will be forced to return it and stick with my CQC-8 instead. I will post again if there are any updates on my detent break in process.
