Benchmade Disassembly Dismay

[Pete84]

So, after sharpening my BM 580 this evening, I found that some of the slurry from the waterstones had gotten into the mechanisms and was gumming up the works. Naturally, I felt a thorough cleaning was in order for a blade I'd just labored on for so long. Seems that was a mistake...

I diagrammed where each screw and piece came from and how they assembled relative to one another. I took everything apart, cleaned, and re-assembled without too much hassle. But, how that I have, there seems to be some blade play where before there was none! I checked each screw... they're all in quite tightly and seem to have gone back right where they belonged... So, that said, why would there be blade play all of a sudden? Is there some trick to reassembling these AXIS assist openers that I'm missing?

Help?!

 

[sgt244]

I know this will seem obvious..
but have you tightened your pivot...? thats pretty much what controlls B-play.

 

[Bryan J]

Assuming you've sufficiently tightened the pivot screw, I'm guessing the observed bladeplay is due to one of two things. The first has to do with overtightening the top two torx bits (at the hilt) of the handle scales. On the Barrage, you only want to tighten these torx bits just enough to secure the scales to the liners. Tightening them beyond this point has the opposite effect of what you'd think--it actually pulls the liners apart, resulting in increased bladeplay. If I recall, it's mainly the torx bits that screw into the bladestop that cause this problem.

If you remove both Zytel grips and the bladeplay is still evident then obviously it's not being caused by overtightening the handle scale screws. In this case my money would be on improper assembly of the Axis assist mechanism. To correct and confirm this, remove the thumbstuds and the bladestop. Squeeze the pivot between your thumb and forefinger of one hand while pulling the blade backward beyond where the bladestop was with your other hand. If you hear/feel a soft "click" then the Axis spring was not properly seated into its channel within the blade hub. It now should be fixed. It's important to now tighten the pivot screw sufficiently enough to prevent the spring from popping out again. If it does, simply reseat by pulling the blade back once again. Reassemble the bladestop, bladestop cover, and thumbscrews. Secure the Zytel grips, taking care not to overtighten the aforementioned screws and you shouldn't have any major bladeplay.

 

[Pete84]

I tried removing the scales and that helped minimally. I also checked the AXIS assembly... seemed to be put together properly, as it didn't click the way you had described. The pivot is plenty tight, but not so much that the blade won't rotate freely.

What I'm finding is:

- Pulling back the AXIS lock with the blade closed causes the blade to open automatically without any pressure on the thumb stud (never had this before, was always very tight and required a good bit of pressure on the thumb stud)
- Blade play (about 1mm, side to side)
- Not locking closed very securely (small portion of the tip is exposed unless you close the blade quite forcefully)

I'm beginning to wonder if I've somehow switched around the Torx screws that go into the scales, as there seem to be two different sizes. One on each side seems longer than the rest. I had placed it in the middle hole on the scale (each side). Thought that was right, but maybe it's not. Have I missed something obvious here? Or should I be sending it to Benchmade to pay for proper re-assembly?

 

[Bryan J]

- Pulling back the AXIS lock with the blade closed causes the blade to open automatically without any pressure on the thumb stud (never had this before, was always very tight and required a good bit of pressure on the thumb stud)

Okay, so my guess was correct. This behavior is a hallmark of an incorrect assembly of the Axis Assist mechanism. Specifically, the tang of the coil spring is not properly seated in its groove. The solution I described above should fix the problem. In any case it will allow you to be certain the spring is seated properly. You will need to loosen the pivot screw a little bit first. Again, completely remove remove both thumbstuds from the blade with a T6 bit. Then remove the blade stop and its cover. Now squeeze the pivot area between your thumb and forefinger while pulling the blade back past where the bladestop was. You should get to a point where the spring starts opposing the force. At some point you should feel the spring seat into its groove (you may hear a faint click). Now start closing the blade (reversing direction), while releasing your squeeze on the pivot area. At some point you should feel the spring pop back out of the groove (another click). You should be able to repeat this over and over again, seating the spring, then popping it out. Of course, in the end you want the spring to be seated. The issue you are having is due to the spring--once it is properly seated the pivot hub will compress about another millimeter and eliminate the majority of the bladeplay you are experiencing.

If you can't seem to fix it, I'd be happy to fix for you if you pay shipping. I'm a big fan of the Barrage line and the Axis Assist mechanism. I know it inside and out.

 

[Pete84]

I think you're right. I'm just doing something wrong executing your directions. I'll probably give it another go in the morning. If that doesn't work out, I may be taking you up on your offer. Thanks again!

Will report back once I've attacked this thing again. One of my very favorite blades, so I'm determined! Haha