BM 940 Issue

P

PittRules55

Joined
Jan 8, 2010
Messages
143
Hello, I have the 940-2 and I first noticed the issue when I set the knife down pivot side first and basically dropped the back end on the table (not more than half an inch of the table) and it made this rattle noise. So i went to inspect the noise and found that If I hold the knife at the pivot end and tab the end of the knife on my palm it makes a loud rattling noise. It only makes the noise when the knife is closed. I have made sure all of the body screws are tightened so i know its not a loose screw causing this. If anyone with a 940-2 could check to see if theirs makes the same noise it would help, then I'll know this is how the knife is and its not an issue just with mine. If it is an issue, help to resolve it would be greatly appreciated.

Thanks!
 
How loose is your action/blade and how far past the inside of the G-10 scales do the screws extend? Not completely sure, but my first thought is that maybe the rattling sound you're hearing is from the blade contacting the tip of a screw(s?) when moved while closed. It seems to be in general agreement around here that Benchmade's QC has been less than great (especially considering their MAP prices) these last few years, so while I've been lucky with my Benchmade's, your problem doesn't completely surprise me.
 
Check your stand-offs, your omega-springs, and your pocket-clip. Loose stand-offs can rattle, but that should happen with knife open as well; pocket-clip can rattle if a bit loose, but again should happen opened or closed. A snapped or loose spring might rattle more readily with the knife closed vs open, but you should be able to get it to happen by holding the pommel-end and tapping the pivot end into your hand or against an object.
 
chiral.grolim said:
Check your stand-offs, your omega-springs, and your pocket-clip. Loose stand-offs can rattle, but that should happen with knife open as well; pocket-clip can rattle if a bit loose, but again should happen opened or closed. A snapped or loose spring might rattle more readily with the knife closed vs open, but you should be able to get it to happen by holding the pommel-end and tapping the pivot end into your hand or against an object.
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Thanks for the reply. So my stand-offs are tight as is the pocket clip. It might help to note that the does comes from the pommel end of the knife only and it makes the noise with the pocket clip removed as that is what I initially thought was causing the issue. It has to be something with the blade.
 
Chariotz4 said:
How loose is your action/blade and how far past the inside of the G-10 scales do the screws extend? Not completely sure, but my first thought is that maybe the rattling sound you're hearing is from the blade contacting the tip of a screw(s?) when moved while closed. It seems to be in general agreement around here that Benchmade's QC has been less than great (especially considering their MAP prices) these last few years, so while I've been lucky with my Benchmade's, your problem doesn't completely surprise me.
Click to expand...
Hello, so I have the action set to where it will freely open up with the least amount of side to side play but it is by no means sloppy. The screws do extend passed the G-10 but i think there is enough space between them and the blade to where there is no contact, plus there are no marks on the blade from screws hitting it. I can agree with you on the QC, I had another 940 with bad action and off centering issues.
 
PittRules55 said:
Thanks for the reply. So my stand-offs are tight as is the pocket clip. It might help to note that the does comes from the pommel end of the knife only and it makes the noise with the pocket clip removed as that is what I initially thought was causing the issue. It has to be something with the blade.
Click to expand...
Hmm... I've not had this problem, so I am just fishing. You've tried holding the blade tightly closed and trying to get the rattle?
What about the inserts for the pocket-clip screws, the ones embedded in the G10 - could it be that one of those it rattling?
 
When you dropped it, the momentum of the blade wanting to still go forward would have moved the axis lock forward slightly. That is normal. Hold it like you are about to open it and shake it up and down. You should get that noise. It is perfectly fine.
The blade on the 940 is heavy, so what you have is the blade tang moving against the axis bar.
 
Well, if you think that's not the problem, then I'm not sure what it could be. There are plenty of other members here with much more experience on this forum and in this hobby than I have, so maybe someone else can help you solve this conundrum?
 
The axis lock most likely has just a slight amount of vertical play within its cutout. Mine is like that. The blade wanting to come open is causing the axis to move. I am thinking that may be the source of the noise.
 
If you’re tapping this way and getting noise it’s very odd....


But if you’re tapping this way and hearing a metal rattle your blade is hitting the side if the scales and that’s normal due to the force making it shift on impact. Make sure there is no side to side play when open and you’ll be fine.
 
If it's a newly developed noise (sounds like it from your story), it could be a broken spring. I have had a broken spring that I first noticed due to extra metal rattling noise.
 
I just tried this with my 940-2. Using Mick_1KRR's video example, the first way I had zero noise. The second way I had a click sound with a little rattle and I could feel a little vibration in the knife. It's not the blade hitting the scale on mine. It's the clip hitting the scale then vibrating.
I have a benchmade deep carry clip on mine so maybe that's why it makes that sound.
 
chiral.grolim said:
Hmm... I've not had this problem, so I am just fishing. You've tried holding the blade tightly closed and trying to get the rattle?
What about the inserts for the pocket-clip screws, the ones embedded in the G10 - could it be that one of those it rattling?
Click to expand...
Yep, I tried that and the twang noise is still there unfortunately.
 
microtech85 said:
When you dropped it, the momentum of the blade wanting to still go forward would have moved the axis lock forward slightly. That is normal. Hold it like you are about to open it and shake it up and down. You should get that noise. It is perfectly fine.
The blade on the 940 is heavy, so what you have is the blade tang moving against the axis bar.
Click to expand...
If i hold it like you mentioned and shake it i don't hear any sound, its only when the butt end of the knife hits my palm. It might be moving against the axis bar but the noise sounds like its coming from the back end.
 
Is the tension on the Axis bar the same as always? If you have a busted spring, it might not be strong enough to hold the blade closed completely. Maybe tape the blade closed and see if it still rattles.
 
Mick_1KRR said:
If you’re tapping this way and getting noise it’s very odd....


But if you’re tapping this way and hearing a metal rattle your blade is hitting the side if the scales and that’s normal due to the force making it shift on impact. Make sure there is no side to side play when open and you’ll be fine.
Click to expand...
So i just checked and It makes a noise if i tap it like the first gif but its faint. If i tap it like the second gif it is the very loud twang noise but I feel like if the blade was smacking the side I would be able to tell with marks on the blade or seeing it move. My knife also only has slight side to side play because i cant get rid of it without making the knife impossible to open. Does your 940 make the loud noise if you smack it on the side?
 
kreole said:
If it's a newly developed noise (sounds like it from your story), it could be a broken spring. I have had a broken spring that I first noticed due to extra metal rattling noise.
Click to expand...
The noise is coming from the butt end of the knife and the axis bar is functioning properly so I can't imagine one of the omega springs are broken, its practically brand new.
 
PWatkins said:
I just tried this with my 940-2. Using Mick_1KRR's video example, the first way I had zero noise. The second way I had a click sound with a little rattle and I could feel a little vibration in the knife. It's not the blade hitting the scale on mine. It's the clip hitting the scale then vibrating.
I have a benchmade deep carry clip on mine so maybe that's why it makes that sound.
Click to expand...
Mine makes a loud noise, if it was faint I wouldn't think something is wrong. I also thought it was my pocket clip as I also have a deep carry clip but I took off the clip to access the one body screw and it still makes the noise so i don't whats causing it. Do you mind seeing if your knife still makes the noise without the clip on?
 
PittRules55 said:
Mine makes a loud noise, if it was faint I wouldn't think something is wrong. I also thought it was my pocket clip as I also have a deep carry clip but I took off the clip to access the one body screw and it still makes the noise so i don't whats causing it. Do you mind seeing if your knife still makes the noise without the clip on?
Click to expand...
Ok , so I removed the clip and tried again. Tapping it like the second gif I still get a click sound but the vibration is gone. I put a small piece of a paper towel between the blade and the scale and the sound stops. So it has to be the blade hitting the scale on mine.

My 940-2 is adjusted with zero blade play and it closes with just a little wrist flip. Not quite drop shut. Hope this helps.
 
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