Successfully adjusted Hinderer XM 18 lock up... somehow.

Heartland_edc

Heartland_edc

Joined
May 4, 2015
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If you don't want to read the full story here, no worries. I created a "TLDR" section down at the bottom. Just scroll down if you want the short version :).

My hunt for a mint XM 18 stonewashed spanto Fatty ended last week, and the knife arrived in perfect shape Tuesday. I looked it over front to back, and from every angle trying to find anything I could percieve as an "imperfection." Not one thing. Lock up was sitting at roughly 35-40%, which I have found to be fairly normal lately with new Hinderers. I thought to myself "would have been nice to see that lock up at about 10-15%" but again, I didnt really consider it a flaw. In fact, the only reason I like the idea of early lock up is because it gives the impression that the lock face will last longer. Its just something fussy that I am happy with when I can get it, but not a deal breaker unless its over 50%. So anyways, all is well except for the digi camo scale that came with it. I quickly ordered a new scale to my liking (green/black) and installed it last night. Heres what happened...

Here's the lock up % before I changed the scale




The steps I took were exactly this:

1. Broke loctite seal on pivot using a couple of pennies.
2. Removed pivot completely.
3. Removed scale screws completely.
4. Set new scale
5. Tightened pivot
6. Tightened handle screws
7. Blade was off center. Leaning towards g10 side. Removed all handle screws and tightened pivot with a folded piece of paper wedged on g10 side to adjust blade centering.
8. Tightened bottom scale screw
9. Tightened top scale screw
10. Tightened middle scale screw
11. Removed paper
12. Adjusted pivot until blade was center

Here's what the lock up looks like now.




I was skeptical at first. I tried applying force to the spine to see if it would fail. It didnt. Then I thought "maybe its just tight? Maybe itll break back into its original lock up position?" So I flipped it... and flipped it... and flipped it. Maybe 200 times since I did this last night. Same lock up. Looks like 15% or so. Im SUPER happy, but i have no idea exactly which step caused this. On a side note, the action is still buttery smooth. The blade easily falls under its own weight and rockets out with either the light switch or push button method. Detent is perfectly medium. Blade is 100% perfectly centered. Anyone have any ideas? I know its been mentioned somewhere here on the forums that this is possible, but there were never any details that I could find. Any help would be appreciated as I would very much like to be able to replicate this on other Hinderers.

***TLDR****

My hinderer was locking up at 35-40%. I changed the scale and put the hardware back in and it now locks at 15%. Not sure exactly what I did to cause it. Looking for an explanation.
 
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I dont recall exactly. But those are the steps I generally follow when taking apart and putting together. And yes - the lockup % change happened when I installed a different scale (new or like new).

Now I am purely speculating so pls do not take it as an a scientific explanation. Maybe just maybe the alignment of screw holes on the scale and the liner is not 100% identical between two g10 scales such that the new one when screwed pushes the liner a tiny tiny bit and as a result the blade is also pushed a tiny tiny bit toward the lock face direction when locked and hence the reduction of lockup %.

Of course this speculation assumes there is a tiny bit wiggling space between the pivot bolt and the blade hole, and it should (otherwise how to push it through the hole?).
 
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Ic. Interesting. Makes me wonder if it's something they could do at the farm, but don't because of fears of accidental disengagement.
 
I have had a similar experience when changing an XM18 scale (to non OEM)...except with my knife, I already had early lockup; so I was not comfortable with the further reduced contact. I disassembled/reassembled several times, without effect; so I removed the new scale. Lockup went back to original with the OEM scale, and was similar when I changed to another OEM scale. I had a friend try the scale on his XM18, and it had no discernible effect on lockup.
 
Sounds like it could definitely be the interaction between a particular scale and liner. Thats what makes the most sense so far anyway. I wonder if the scale and liner are made to fit each other, or if they just sort of "grab from a pile."
 
Roll up a piece of sand paper and slightly enlarge the scale screw holes just by a tiny bit. Fixed.
 
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