Mantra bearing race issue SOLVED

[Evil D]

Hey folks, sorry to make another thread on this topic, I know we already have one going but I wanted this to be easy to find for anyone who's concerned with this issue. Sorry if the sound is low, it's late and all the sane people in my house are asleep. Also the video does cut off at 5 minutes but I was heading into rambling territory anyway so you didn't miss much after that and I had said what I needed to say about the Mantra so I didn't bother reshooting the video.

https://youtu.be/Kqfeop-ATew

*To be clear, I don't think you have to take your knife apart to do this, just drop some liquid lube in the pivot and tighten it down and work it out. The only reason I took mine apart was to inspect the washers and to grease up the blade/pivot with Vaseline.

If I had thought about it I would have shot some video of the knife being apart and what I did, but here's a pic I took of one of the washers. If you look close you can see the dents and the groove that had already started to develop just from fiddling with it prior to taking it apart.



So, hopefully that helps some of you. I suspect this is just the nature of the beast with these bearing pivots. I also suspect that the issue has to do with the bearings in particular with this knife, because I didn't have this issue with my Southard and haven't seen it mentioned with the Domino/Dice. I also suspect that the reason for that is it seems the bearings used in the Mantra are significantly smaller than those other knives use, which means if you use the same torque on the pivot screws during assembly (seems reasonable that they would), there's a good chance that the smaller ball bearing is going to have an easier time denting the washer. Some have asked, why have washers at all? The problem with not having washers is, these bearings are no doubt made from some hardened tool steel, which is going to be much much harder than the titanium scales, and over time the bearings would wear a groove right into the Ti (probably within the first 100 openings or less) and then you would have introduced play into the pivot that you can't fix. With washers, at least they can be replaced. I don't know if changing the washer material would make a difference, perhaps a harder material would prevent the denting?

[Surfingringo]

Good info Dave! I hope this encourages more folks to pick up a Mantra. It is one of the most under appreciated knives in Spydercos lineup imho. For me it's like a Delica on steroids...with better ergos to boot!

[Evil D]

Yeah I was fiddling with it most of the night, then compared it to my Military and saw that it only gives up a bit over a half inch of edge length and does so in such a small package, it really is a great design. I see it as kind of a flipper Delica/Caly hybrid.

[ABX2011]

Nice vid! Good solution for people who like tinkering and don't mind voiding their warranty.
Call it a teething problem. Spyderco still needs to figure out a way to make these smooth out of the box. And I'm sure they will.

[Evil D]

Nice vid! Good solution for people who like tinkering and don't mind voiding their warranty.
Call it a teething problem. Spyderco still needs to figure out a way to make these smooth out of the box. And I'm sure they will.

I don't think it's necessary to take it apart to do this, just drop some oil in the pivot and tighten it down and work it for a while then loosen the pivot.

[Brock O Lee]

Good info! Thanks...

I suppose the inverse is also true... If you have a smooth Mantra from the factory, you will probably develop slight side-to-side blade play as the washers break in, and would need to tighten the pivot eventually.

[ABX2011]

Nice vid! Good solution for people who like tinkering and don't mind voiding their warranty.
Call it a teething problem. Spyderco still needs to figure out a way to make these smooth out of the box. And I'm sure they will.

I don't think it's necessary to take it apart to do this, just drop some oil in the pivot and tighten it down and work it for a while then loosen the pivot.

Good point. Makes me want to get another Mantra.

[Evil D]

Good info! Thanks...

I suppose the inverse is also true... If you have a smooth Mantra from the factory, you will probably develop slight side-to-side blade play as the washers break in, and would need to tighten the pivot eventually.

Possibly, but I never had this issue with my Southard. Again, that could have something to do with the size of the bearings. A smaller bearing is going to focus pressure onto a smaller surface area, so the same torque spec on the pivot screw of a Southard may be enough to dent the washers in a Mantra.

Another thought, and something I actually meant to do but forgot, it's probably a good idea to do this slowly instead of just cranking the pivot down all the way at once. If anyone has ever used a tube/pipe cutter then you'll understand the concept there. You should probably snug it down, then work the pivot, then snug it more and repeat. By going all in like I did you could very easily create more dents.

I think this issue could be resolved with harder steel washers, but I'm curious if there could be some drawbacks from that. I have to assume that if the bearings can live with rolling on M4 on one side, then they can live just as well with another hard steel on the washer side.

[Able Dog]

As to your question about changing the washer material. Brad Southard has talked a little about the washers used in his midtechs. He made them out of heat treated blade steel. I imagine they were also significantly thicker than the ones used in Spyderco's knives.

A lot of that would be excessively expensive to implement on a large scale. But the thickness of the washers could be increased a bit I think.

Good point on the bearing diameter. I haven't handled a Mantra but your theory makes sense.

[Holzfaeller]

That seems like a lot of effort to make a new knife operate correctly. My PM 2 works flawlessly as it did the first day. I'll take reliable simplicity over high tech and high cost.

[Evil D]

That seems like a lot of effort to make a new knife operate correctly. My PM 2 works flawlessly as it did the first day. I'll take reliable simplicity over high tech and high cost.

Wouldn't it be great if this knife had more to offer than just a bearing pivot?

[mrtodd777]

I guess the one I just received doesn't have this issue, or at least I cant notice it. Other than some scratches right out of the box this thing is dang near perfect!

[awa54]

It sure seems like all that would be required to put this whole thing in the rear view would be to make the shims out of hardened steel, or even better switch to roller bearings from balls (caged rollers are available, though I'm not sure if one that has the same dimensions is currently produced).

This is certainly a good work-around though, especially since it can be done without any special skills or tools, beyond owning a torx driver.

I'd be interested in the dimensions of the steel washers and bearing race... might be pretty easy to either replace the washer or convert to PB bushings.

[Evil D]

Making the washers thicker isn't an option, that would change the width tolerances in the pivot. I guess they could recess the washers into the scales more.

Ultimately my point with this thread wasn't so much that you have to do a song and dance to make this knife smooth. All I did was accelerate the break in process. Anyone with this knife who just uses it enough will eventually come to this result.

[Ncmiked]

I flipped my washers as a work around but I think I'll try your method next time I clean it.

[willydigger]

I flipped my washers as a work around but I think I'll try your method next time I clean it.

I flipped mine too. I plan to leave it like that, but I plan to use Vaseline next time as a lubricant.

[dplafoll]

My Mantra was smooth enough before, but after seeing this thread I thought I could improve it. Well I tried this and it didn't get better; it actually got worse. So I took it apart yesterday, and not without some trepidation, having never taken apart a knife on bearings before. But all went well, and it turned out my washers had gotten dished, probably by me, and were causing more friction than before. So I cleaned out everything, flipped the washers over, gooped up everything with vaseline, and reassembled it. And at first it was pretty stiff because the washers were still "3D", but counter to my own instincts I cranked the pivot down a little and it loosened right up, and now it's much better than it ever was before.

Thanks EvilD for this!

[4life]

Hi, I saw your vid on YouTube and left a reply there but thought I should also write something here.

*caution do not tighten as hard as you can without stripping screw*
Everyone has different strength and ability to tighten without stripping, and doing this actually would harm more than help.

Following EvilD's vid, my washers actually curved and formed around the bearing housing which cause the knife to be unable to be flipped open, even with it so loose that it wobbled side to side drastically.

(Because of there wasn't any comments besides one, I panicked and thought perhaps it was a troll vid, to trick people into messing up)
I opened the knife back up and saw that the bearings actually left very slight indents into the TI scales, also leaving a slight track on the blade.

Now that the washers were curved, forming around the bearing housing I thought that's the end... however I figured out a solution: flatten the washers out.

Using a tool to press the washer flat, it fixed everything.
I would recommend to anyone who tightened the pivot and it got worse as described above to take the washer out and flatten it back out using either a press or some other tool that is able to apply enough force to completely flatten it.

Now it's as smooth as anything, and to my nice surprise saw that EvilD left a reply to my comment and restored faith in people, it wasn't a trick video lol.

Tommi

[Evil D]

My washers were cupped from the factory, I think there's another video about that. It sounds like you may have tightened them down too much all at once, you've gotta do it a little at a time and then work the pivot, the tighten more, then repeat. I guess my experience could be a fluke but I doubt it.

[4life]

I read about doing it gradually, but that was after I had already watched the vid and tried it out. At least we know what to do from now on.
Mine was curved from factory too, but didn't fully form around it til I tried to fix it.
Like your solution suggests, we just need to help it wear in. Just tightening it a little more, and I think using less lubricant to give it a chance to "cut" a track into the washer is all that's needed... plus having a nice flat washer.

I'm debating getting the mantra 2, if I do, I may just try flattening the washer out and seeing if that's all that's needed.

P.S did the bearings scratch into your blade tang? ... or even the scales?