Steel Lockbar Inserts - Question

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I've read that steel lockbar inserts dramatically increase the life of a lockface, yet I've also read that manufacturers use replaceable inserts so they can be swapped out when they 'wear down'. These two points seem kind of contradictory considering the relatively short time that inserts have become popular.

I have personally never worn out a lock face, regardless of whether it has an insert or not, but I'm curious whether anyone else has ever had to replace a steel insert. Is it common for a steel insert to wear down to the point that lock rock becomes an issue? Will this be a common issue down the road for knives with inserts, or are they expected to perform for a lifetime?
 
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Well. It's much cheaper to replace the insert than the blade. So I'm thinking it's mostly a cost thing. I have never worn down either the lock face or the lock insert to the point where either need to be replaced.
 
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Well. It's much cheaper to replace the insert than the blade. So I'm thinking it's mostly a cost thing. I have never worn down either the lock face or the lock insert to the point where either need to be replaced.

The insert is meant to prevent wear to the lock bar where it meets the tang. The blade tang itself should be OK regardless of what the lockface is made of. I'm just curious if anyone's ever seen a steel lockbar insert wear down.
 

ATJ999

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I have worn out a Ti lockface before, but never a steel lock insert. They are great and can easily last a lifetime or two. But for some reason, wear or otherwise, it is nice to have that easy fix.
 

palonej

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I have worn out a Ti lockface before, but never a steel lock insert. They are great and can easily last a lifetime or two. But for some reason, wear or otherwise, it is nice to have that easy fix.

I'm curious.......which knife was it that you wore out the lock face on??
Thanks!
I have a bunch of Ti frame locks. Some with and some without inserts. I haven't seen any wear, after break in, on any of them.
Joe
 

cricketdave

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I've seen a couple worn to the point that there was play in the lockup. I haven't done that to my personal knives. Seems like a ZT was one and I know there was a big mess of a thread over a Chris Reeve.
 
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It may be as well that the steel-on-steel interface of a lock insert(vs titanium) produces less lock stick, especially in flippers. I've actually had to remake an insert on my Spyderco Domino using Ti, and it doesn't seem to wear after reaching a certain point on the tang. The original steel interface did disengage easier tho.

In case anyone gets the wrong idea, the original steel insert didn't wear out - it was very slightly warped, and in trying to correct that, I forgot that 'hardened' also means 'brittle' ;p
 

tiguy7

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Carbidized coatings are usually Tungsten Carbide or Titanium Carbide. The former is usually applied over steel and the latter over Titanium. The stuff is applied in a D/C arc where the shooting electrode (WC or TiC) sputters plasma on the intended surface. The coating is not very thick but is quite hard >70HRC.
Some makers Carbidize the non bevel side of a chisel sharpened blade so that the hard layer is exposed on the micro edge. This works well for softer substrates like Titanium.
 

AJR576

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I posted the same question a short while ago and most responded that the primary reason for steel inserts is to reduce / eliminate lock stick.

I asked because I have several titanium frame / liner lock knives including a ZT561, BM Subrosa, couple of Emersons, etc.

After an initial break in, any lock stick was gone, all are locking at 50% or less, and all lock up tight with zero play.
 
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I posted the same question a short while ago and most responded that the primary reason for steel inserts is to reduce / eliminate lock stick.

I asked because I have several titanium frame / liner lock knives including a ZT561, BM Subrosa, couple of Emersons, etc.

After an initial break in, any lock stick was gone, all are locking at 50% or less, and all lock up tight with zero play.

Have you noticed the lockup progressing toward the presentation side at all on your steel insert knives, or has it remained consistent even after break-in and use?
 

AJR576

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My zt801 and zt550 have the steel inserts and they both have very early lockup (around 20/25%). The 550 is new and the 801 has been flicked open a bunch but hasn't seen any "hard use". Honestly, I'm hoping that they do eventually wear in a bit since I'm more comfortable with lockups at around 40-50%.
 

Gideons

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The issue in my opinion with the steel lockbar insert is that it causes increased lock disengaging. Now, this is my opinion however. But, I think many companies just added it to the knife, not thinking about how it will affect the locks geometry. Not to mention, one of the reason the locks wore down titanium on steel blade is titanium is softer than hardened steel. This "softness" creates friction and thus helps prevent lock slipage/disengaging. So... I am torn on this new steel lockbar insert. The steel bar insert ruined an amazing knife for me (ZT 0620) the lockbar geometry was just off because of insert and the lock disengaged insanely easy. Which made it in my opinion unsafe to use. This steel lockbar insert can extend a knifes life but also ruin a knife. Its usage is still very new, so hopefully soon companies will perfect the steel lock bar.
 
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Carbidized Titanium FTW:thumbup:

^^This.

A carbidized lock face + a good lock geometry (proper lock bar tension + tang) will give you a lock bar that will take longer to wear out than you will...without little adjusting screws and metal inserts...I personally don't need more parts on a knife.

See CRK lock bars to realize that with some attention to the details, it can be done.
 
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See CRK lock bars to realize that with some attention to the details, it can be done.

Agree 100%. I collect CRKs, and until recently my collection consisted of nothing else. I recently picked up a couple Shirogorovs, and I love them. I'm just curious about the steel lockbar insert's longevity. Especially since my Shirogorov Hati has a small lip that will prevent the lockbar from traveling after a while. See photo below:



Typically with Ti lock faces the knife will age gracefully (and avoid lock rock) by allowing the lockbar to travel further toward the opposite scale. That way the Ti doesn't wear down too far in one spot. With the Hati pictured above that will be impossible because of that little lip, but perhaps steel will not wear like Ti does?

That's basically what I'm asking. Is this something to be concerned with, or will the insert stop the lockup from wearing down / traveling over as the knife ages?
 

ChazzyP

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Interesting topic, Anarchy, and one that, along with any discussion of lock wear, travel, geometry, etc, always raises a lot of opinions, theories, and hackles to boot. So far, an interesting and civil discussion here. :thumbup:

A few random thoughts and really no conclusions:

>My impression has always been that the purpose of steel lock-bar inserts is indeed two-fold--1) to prevent a softer titanium lock-bar from wearing more quickly than the harder steel tang/interface of the blade, and 2) to minimize or eliminate the lock-stick that frequently occurs between dis-similar materials, i.e. titanium and steel, and is exacerbated by the presence of lubricants.

>Steel inserts are certainly popular and, while one might debate their usefulness/function, there is no question that marketing the feature du jour is an effective way to sell knives. Not saying that's a bad thing, either, just sayin'.

>I've wondered about this "early lock-up" thing--another popular concept. I've always assumed that those who thought that a good thing were thinking about eventual wear and longevity. Those that were thinking, anyway. I've looked at some knives whose "early lock-up" has been touted in ads or sales threads and have been concerned that there is so little engagement there as to be dangerous.

>In his post above, tiguy, who is an engineer, gives an excellent description of what the carbidizing process is and what its applications are. As carbidizing is intended to add a hardened (harder) layer to a substrate and inasmuch as carbides are the particles in steel blades that do the cutting, I wonder if the effect of carbidizing a lock-bar is sorta like robbing Peter to pay Paul (or rather enriching Paul to the eventual impoverishment of Peter). Do we harden the lock-bar only to wear away the blade tang? I had thought that carbidizing lock-bars, as demonstrated on several Youtube videos, was more a method to cure lock-rock or poor lock-up in ill-performing knives.

>I had thought that CRK's process for treating the titanium lock-bar was not carbidizing but is carburizing, which is essentially heat-treatment to harden the lock-bar. Tiguy can help with the definition. I recall seeing somewhere in CRK literature that their process included heating up the end of the lock-bar with a torch, but my old filing cabinet of a memory is quite full and some things are surely mis-filed.

>Anarchy's pic of his Hati's lock-bar shoulder had me scrambling for a flashlight to check my two liner lock Shiros (F3 and 111) to see if they had that feature. My newest Shiro is an Axis-lock Tabargan and thankfully exempt from this discussion. The two former do not have shoulders, though they do have steel inserts. While the shoulder will prevent locking over-travel (as opposed to the more well-known disengagement over-travel stop), I wonder what might happen if enough wear occurs to engage the shoulder to the point that the lock-bar develops rock or play and is prevented from further engagement. Is the shoulder therefore a sort of early-warning system?

>Finally, on the subject of lock-bars wearing out, I recall something that Ann Reeve wrote to the effect that lock-bar engagement over-travel is only an issue when the lockbar hits the blade. When that happens, send it in. The only knife I have that's developed any major change in engagement travel is the Sebenza 25 that I bought here last July, and that knife uses the ceramic ball interface. That one has moved from about 50-60% lock-up to around 75-80%, but that also occurred after considerable tinkering with centering (adjustable pivot), washer polishing, and a change in lubrication. Where that change may be some cause for concern, it's not near touching, and if it does I'll just do what Ann says and send it in. I like that all my CRK lockbars fully engage with the blade ramps and are not hanging half-or-more off like several of my other knifes. Just seems more solid to me.

Anyway, like I said, just a whole bunch of random thoughts and observations above. Either food for thought or food to be left on one's plate. Also, I'll go back and proof-read as is my custom, but as someone once said "Auto-correct is my enema" especially when it comes to carbidizing, carbonizing, carburizing, and any compound word with lock in it.
 
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I appreciate your thoughts, ChazzyP!

I was under the impression that CRK heat treated the end of the lockbar higher in order to increase life / reduce lock stick. I was not aware that they did anything beyond that, but I've always been curious about the triangle of silver material in the corner of the lockbar. Perhaps that is the result of the process described above?

The shoulder on my Hati is also present on every Shirogorov 95 I've ever seen. I don't know how much lockbars with steel inserts travel over time (hence this thread), but if they do indeed wear down and travel over through use that shoulder is rather concerning, as it will inevitably prevent further travel and lead to vertical blade play.

I thank you for taking the time to write that post! Good stuff. Hopefully someone with more knowledge of steel insert lockbar behavior will enlighten us below.
 
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palonej

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I have 2 knives with that shoulder on the lock bar, like Anarchy posted,.....both Benchmades. 790 & 761.
BM then went and installed an adjustable lock pin.....shaped like an octagon.
Not too sure if this was done to compensate for wear or if it is there for adjustment only. I remember watching a vid by that sanctimonious dip stick, apostle, and he trashed it for some reason.
Does anyone know if they came up with this feature to combat what we're discussing??

Great post Chazzzzzy!!
Joe
 
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