On one model 710, it looks like the frame lock engages very far left. Maybe it makes contact with 1/8th of the knife part when opended.
Obviously Im not going to complain about a $5 knife from China, or send it back, Im just wondering if its safe to use, or just poor quality on the machine that bends the frame, or its supposed to be like this until it wears in or whats up?
Before this Ive only had one SRM, it was another model 710 and to to me it was perfect, so I just thought every SRM would be made with no issues. Just like when I buy a Bic lighter it doesnt have problems in consistency, they are all the same.
Im not a liner-lock/frame-lock/knife expert, and Im not trolling, Im just wondering.
My order also contained an SRM tree-camo 707 with the same issue.
Many thanks.
PS - Ive oiled the knifes with 3-in-1 oil and tried to flick them a bit, but didnt see much difference.
I haven't had that degree of problem with liner lock engagement on the SRMs. I've received a couple that appeared to have only 50% engagement when opened for the first time, but after a few authoritative wrist-flicks they settled in to about 80-90%. I don't mind this since the lockup feels positive and strong, and they will only wear in more fully with continued use.
That's what a frame lock is supposed to be like when new. As it wears on the back of the blade tang it'll eventually go further and further to the right.
Hi - Thanks for the comments. Thats why I like to ask the expers here, instead of just complaining to the factory, LOL.
So as I understand now from your explanation, in time the blade tang should get worn away by the frame lock, then the frame lock will move more inward? So this means the frame lock material is stronger than the blade tang material?
Anyway it makes sense, I thought the frame lock was pre-tensioned to only be bent a little bit. But if I disassembled the knife, would the frame lock scale be tensioned all the way inward?
First question, no, the blade will be harder than the lock - but it's steel on steel, so they'll wear each other regardless.
Second question is yes. Liner and frame locks are called "self-wearing" locks - as they knife is used and steel is worn away, the locking bar will move further and further over to maintain a movement-free lockup. This helps prevent lock and pivot failures, and it's the sign of a properly manufactured knife.
If unsure how well the knife locks do a spine whack test (example) to get an idea how secure it is. If it holds it doesn't matter that the liner is only making little contact with the blade. If not you can try to sand of a tiny layer of atoms from the tip of the liner.
jekostas, correct me if I'm wrong. The two main forces that maintain engagement of the liner lock are provided by the spring tension of the liner and the friction between the liner edge and blade tang. Friction is proportional to surface area, so ideally the full surface of the liner edge would be in contact with the tang to maximize that friction component (and preferably on the left side of the tang to ensure long lock life).
For this reason, I'd be leery of any liner lock that had minimal (say, less than ~50%) engagement because of the significant decrease in friction. Perhaps I am overestimating the role of friction in normal use, as friction may be more critical for keeping the lock engaged during abnormal spine whacks. But at some point there is a limit of safe engagement for any use; I would think only 1/8th of the thickness of a liner edge would approach that, if I interpreted esrevenge's situation correctly.
I have an interest in mechanics and knives, but am not an expert at either, btw.
I just received my 710 and I would say about 80% or more of the frame lock contacts the blade tang. I don't have the knife here to look at since my wife took it over so it may be more. I am very confident in the lock up of my knife. The only way the lock on my 710 contacts less of the tang is if I don't "snap" the blade into position.
Seriously I buy the knife and have to wear it in myself? LOL, how long should it take for friction to eat away metal so it locks properly if I open the knife a few times a day? Like 10 years or something?
Friction doesn't really have much to do in terms of strength in lockup for frame and liner locks.
For liner locks, the entirety of the locking strength comes from spring tension holding the liner in place, and for frame locks this spring tension is supplemented by the fact that when the knife is in hand, your hand will naturally keep the lock in place (which is why frame locks are often considered stronger than liner locks). esrevenge, as long as you're holding the knife in your hand, your hand will keep the frame lock from closing in usage.
The other side of the equation is that with proper usage and technique, a liner or frame lock should *not* be taking the majority of stress in knife usage. Positive pressure on the blade (you'll have to read my Primer again for all the terms) is transferred from the blade to the stop pin and in to the handles of the knife and as such the lock has no pressure on it. Liner locks are really only meant to take minor negative pressure from tip prying or digging. Frame locks can withstand substantial negative pressure with proper grip, such as from a stabbing motion.
Huny74, I've said it before but the spine whack test is a test designed for knives to fail, and not representative of any kind of stresses the knife would be subjected to in real world usage. The only type of lock that will consistently pass that test is a back lock and even then you have to be careful because repeated spine whacks will eventually destroy that lock as well. It's just not useful for anything but making pretty videos about, unless you're an outdoorsman and have decided to consistently do batoning with your folding knife (at which point I'd just be looking at you strangely).
esrevenge - if you're not happy with the way the knife is right now, go out and use it. As the pivot loosens up slightly the blade will have a microscopic amount of play, allowing the locking bar to move over further. That or you can use a torx driver to loosen the pivot screw about 1/16th of a turn and it will do the same thing.
That's why I said "...get an idea of how secure..."
Any knife that fails this test easily (ie when gently whacking the spine) is IMHO less safe than one where the blade is not closing when applying the test. I do this with all my locking folders when I get them new and can't see what's wrong with that. Out of about 20 locking folders I own only 2 have failed because of constructional flaws (liner locks with wrong angle at the base of the blade) and not one got destroyed. I think to destroy a working lock you would have to use much more force than I actually use, maybe we have different definitions of what a spine whack test should be good for? My intention when doing this test is, like I said above, to get an idea of how well the lock is doing its job for this to do I need only moderate force. Maybe there are people who whack their knives so hard and deliberately that the formerly properly working lock brakes, but I haven't met any of them yet, and yes, I would look strangly at them too.
You can send it to me. I'll be happy to wear it in for you.
Seriously though, which would you rather do, buy a new knife with lots of wear room left on the lock or buy a used knife with a well worn in lock that engages fully but has little wear life left?
As long as your lock engages enough to stay locked in normal use I don't think you need to worry. Enjoy your knife, and in time it will engage more fully.
If you have the black/ camo-coated 710, that would explain it. There is some coating at the end of the liner-lock, but this will wear off pretty quick and then the lock will engage perfectly. At least it did for me. I have lots of Sanrenmus and they are all great. Now under order a bunch of 763 and the Navy K-631.
Thanks, that makes sense. I accept that the variance with these SRM lockups is within their quality control standards. I'd rather have a knife with partial liner engagement on the left side than full engagement in the middle, but for a $7.00 knife I'd be happy enough with both. I would be less happy if the same condition existed with a $100 Spydie or BM, since I would expect perfection - both functional and aesthetic.
I just received my second SRM710 and the lock engages at about 55% I am very confident in the lockup of all four of my Sanrenmu knives so far.
I have only minor complaints and they are only about minor cosmetic flaws.
So far I have the 763, 711 and two 710’s since my wife now carries the first 710 I bought
oh by the way the lockup on my 711 is at about 60%
I’ll be buying more SRM’s in the future and I will keep this thread updated as I get them.
Yes, thank you for the reply. As I become more familar with the knives I understand about the mechanism - at first I did not know. And as people say, the locks do break in after a while, and become smoother and more pleasant to operate. Better too far left than too far right.
And to update, my 707 is PERFECT now - as another poster said maybe it was the coating, but it locks up very nice, about 1/3 in, just about perfect. I used a bit of oil too - you have to break it in a bit.
And to ashuang0731 - Since you are from China...can you please comment some more on SANREMU in China? Are the SRM knives popular there, can you buy them locally at common stores? Or do people in China order from the same stores as on this forum? Is it common in China for people to own several SRM knives, or are they more expensive in China for locals to purchase.
Also is SANREMU the top brand for these types of knives in China..are there other Chinese brands we dont know about...?
