Difference in early model # SW Tilts and later?

jill jackson

jill jackson

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Sep 5, 2006
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I traded for a SW Tilt and it's on the way, I've heard there's a difference in the lock-up on the early and later produced? Can anyone clarify this for me?
 
the early ones had a curved lock face then they switched to a straight bevel
 
are u familiar with the striders at all? they used to use a curved lock face and then switched to a straight one. what happens is as the ti wears it starts to contact the curve and when you put pressure on the blade it would slide over and catch on the flat. thats what they call lock rock, having the straight helps to prevent it
 
I know about lock-rock, not Striders, but I've seen plenty of lock-rock. OK, thanks a bunch, I'd just heard there was a difference in the SW Tilt's lock-up.
 
I have ser# 160, mine has the curved lock face, and its starting to get lock rock :(

Hopefully you got a later number....
 
jill jackson said:
Will/can, Kershaw fix it, or is it just too bad? And what # did they change on?
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Been too lazy to contact them yet to be honest, but hopefully they do. Maybe Thomas can chime in with a possible answer. Mine isint at the point where the blade "wobbles" between the stop pin and the lock bar, but you can hear and feel that the process is beginning.

Not sure what number it was changed on.
 
I just got mine and it's lock-bar face is straight, the blade tang curved, there is no play whatsoever, the # is the double issued 209! But, irregardless of anything else the knife is very nice.
 
Made me look! My 4001SW #019 has a straight lockbar and concave tang face. Lock-up was fine as delivered; edge sharpness was not so good. After some use - and Sharpmaker time - the lockup is still great and the edge is appropriately sharp.

Stainz
 
What happens with the old Strider lock bar interface (radius tang grind) is when the lock bar works itself into the "cup" on the tang over time and use, the lockbar is too short by an extremely small amount but enough to translate into the vertical play you get with lock rock. A flat angle grind on the tang and sometimes the lock bar face too, prevents this from happening as much or at all. That's why the Strider fix is a larger stop pin. That places the lock bar face back to the left and outside of the "cup" again. In effect, the larger stop pin lengthens the lock bar again by creating an earlier lock up by virtue of the blade stopping earlier.

From my experience, only the Spyderco Military manages to do the radius tang grind effectively and without a reputation for eventual lock rock. This is probably because it uses a steel lock bar that is thin rather than thick like frame locks can be. The thin, steel lock bar seats itself much better inside the "cup" and stays within a tight fit. The steel lock bar doesn't wear as fast either. Other than that, what I see is many makers and MFG's are abandoning the radius tang grind in favor of the straight angle now.


jill jackson said:
I know about lock-rock, not Striders
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I've owned 4 SW Tilts and the lowest number I had was 24 and it was the best out of all of them. The carbon fiber was flawless and the lock up and kvt was smooth and precise.
 
chester22 said:
I've owned 4 SW Tilts and the lowest number I had was 24 and it was the best out of all of them. The carbon fiber was flawless and the lock up and kvt was smooth and precise.
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Unfortunately, everything was amazing at first, the problems came with the lock bar working into the tang over time, with use. Its quite a shame, hopefully I can get mine resolved with KAI at some point
 
Im interested to know what recourse those of us that have the radius-tang on our Tilt's. Could they just not regrind the tang to remove the radius? Love my SW Tilt but now worried I bought a lemon especially now that I foudn out they changed the radius grind to straight. Thanks for any input.
 
Haven't manufacturers been using the radial tang grind as long as framelocks have been around? There's so many knives out there made this way. If it was a real design flaw you'd think we would have heard more about it by now. I hope it's an isolated thing and my framelocks don't develop this problem...
 
Many are moving away from the radial grind but I also believe the problem is exacerbated with thicker, titanium lock bars such as on many frame locks. That is just my own observation. I have seen it mostly on frame locks but some liner locks. If the lockbar effectively becomes short when it works it way in the cup of the radius (50% lockup, give or take) then there is nothing you can do except a repair. I have seen older Striders where the lock bar sat in the cup of the radius and didn't have enough grip or lock bar tension to grab the steeper angle of the tang on the right side of the grind if you look at the lock up with the lock bar facing up. In some bad cases like this, the lock bar can just float in there. Climbing or gripping that steep grind on the right side of the radial tang grind requires a lot more lock bar tension than is typical. You can try bending the lock bar but that requires disassembly and will probably be temporary in some cases. The reason "I" Blame the thicker titanium lock bars is because they wear more than steel lock bars anfd they wear more on the inside part of the lock bar face so as the lock bar face is working its way rightward with use, material is wearing away too making he contact point effectively shorter. By the time the lock bar face is in the cup of the radius there is less material left and you have a shorter contact point now. That's just a personal, uneducated assumption of mine

I'm sure the geometry of individual MFG's/maker's grinds has a lot to do with this happening or not too.

If you study the Spyderco Military, where I personally feel the radial tang grind works as it was intended, you will see a thinner, steel lock bar and a lock bar with a LOT of spring tension. I believe this is why Spyderco is succesful with this tang grind method on the Military. I have never had a Military out of a dozen or more, that wasn't rock solid for as long as I owned them.

Degree of angle means a lot too. Even on straight angle tang grinds. I have seen various proclamations of what that angle should be but I have seen 8 degrees mentioned more than others although most I have read are in the 7-10 degree range. You aren't just chasing solid lock up, you are also trying to achieve a balance between lockup and smooth lock bar release.

As simple as a frame lock or liner lock may seem, there is a lot going on and the slightest of missed tolerances translate into things knife lovers don't like . . . It's a fine balancing act to properly set up one of these locks and make them last too.

leafstorm said:
Haven't manufacturers been using the radial tang grind as long as framelocks have been around? There's so many knives out there made this way. If it was a real design flaw you'd think we would have heard more about it by now. I hope it's an isolated thing and my framelocks don't develop this problem...
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leafstorm said:
Haven't manufacturers been using the radial tang grind as long as framelocks have been around? There's so many knives out there made this way. If it was a real design flaw you'd think we would have heard more about it by now. I hope it's an isolated thing and my framelocks don't develop this problem...
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The radius (change in height and change in change in height) is not the same on each knife with it. Some are closer to straight than they are to other radiused ones. That one design works or doesn't work doesn't mean they all do or don't :)
 
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