Maxamet damage: Scratching my head

[Eli Chaps]

Exactly my point, you did not have all the information to assume it was a bad sharpening job. I also stated that I have 2 other knives in maxamet that do not have this problem.

anyway , no more feeding the troll.

This is Big Brown Bear aka DeadboxHero . He's an awesome resource.

 

[Blues]

Fair enough.

Thank you. You won't regret it.

 

[DeadboxHero]

A ArenaRed

Well, my apologies for coming on too strong.

No one likes their sharpening insulted.
My bad. I was just trying to highlight that the problem needs to be addressed with the sharpening first before moving towards more complex or exciting conclusions "Rule things out"
"Tv is not working, Is it plugged in?"

It can be difficult to communicate on forums due to the lack of tone and body language to express the subtleties. Sometimes I'm just very direct and to the point about things.

I highly recommend using the rule out method for problem solving and sharing so those that are reading can follow along without needing to extract pertinent information to reach the same conclusion.

 

[ArenaRed]

Thank you and I shouldn’t have been quick to judge. My apologize for that. Word on the street is that you’re a good guy .

one thing that I did to the blade was force a black patina on it ferric acid. Then I re sharpened it. I wonder if that may have penetrated into the secondary edge and broke it down.

 

[000Robert]

Maybe the steel has impurities in it or something happened in the heat treat. Sometimes people do stuff like maybe a disgruntled employee, or a wacko, or just a bad chunk of steel that Spyderco used. When I was a mechanic, once in a while I would see brand new parts that were defective.
At first I was thinking that a sharpening system where you sharpen back and forth may overheat the edge and ruin the heat treat because it would not take much friction to overheat such a small amount of steel IMO. But when ArenaRed said that he used a WE I kinda ruled that out unless he's one of those guys that tries to sharpen 100mph.
I would love to be able to check the friction heat of sharpening at an edge, but I have no way of testing it. Is there someone that has found a way of doing that?

 

[ArenaRed]

I received the Native 5 back from spyderco. Their representative called me when they had looked at the knife and told me a number of things that I could believe and some that I could not understand.

"maxamet does not like a fine mirrored edge." (my my pm2 and para 3 are ok with it)

He also said that because of the forced patina he could not replace the blade under warranty.

He offered to have the edge re sharpened and have the blade rockwell tested. He called back and said the rockwell came back ok.

I received the knife back with a good resharpened edge and it was sharp.

MY conclusions is that the ferric acid bath I subjected it to may have penetrated the edge and when I sharpened it , I did not remove enough material to get back to the more stable part of the edge steel. My pm2 and para 3 have not been taken into the ferric acid bath and therefore have not had that acid penetration.

Bravo and thank you to spyderco.

On other note. I did get it back with some bad side to side blade play. I contacted them about it they just told me to tighten the pivot and I did before contacting them. No resolution for that problem.

Hopefully this does help anyone wanting to force a full blade patina like i did. ( I did this with a k390 police and it sharpened perfectly well)

 

[Twindog]

I haven't used Maxamet, but I'm seeing a lot of problems with this steel, as Spyderco heat treats it. Many users are fine with the blade; many have experienced chipping and breaking.

S30V was like this when it first came out. Because some makers were using a quench that was too slow for that steel, lots of people reporting chipping. But lots of others did not.

Spyderco's response has not been good from what I've seen. Denying a warranty claim because the blade was given a patina is unreasonable.

 

[King of the Cheese]

I haven't used Maxamet, but I'm seeing a lot of problems with this steel, as Spyderco heat treats it. Many users are fine with the blade; many have experienced chipping and breaking.

S30V was like this when it first came out. Because some makers were using a quench that was too slow for that steel, lots of people reporting chipping. But lots of others did not.

Spyderco's response has not been good from what I've seen. Denying a warranty claim because the blade was given a patina is unreasonable.

Slippery slope. Putting a “forced” patina on a blade is technically a modification to the stock configuration. If that’s okay under warranty, how about acid etching? Stone washing? Bead blasting? Where does the line get drawn.

If I’m a manufacturer, my warranty logically would cover the knife, used in stock configuration, as a knife is intended to be used. Any deviation from that and a manufacturer is off the hook as far as I’m concerned.

 

[Alberta Ed]

Haven't tried Maxamet (yet) but in my experience, high carbide content super steels tend to cut better with a coarser edge -- no higher than 600 grit. You can get a polished edge but those don't seem to have the same "bite".

 

[DeadboxHero]

It depends on the stones used, most folks are using alumina abrasive waterstones to get a higher finish on knives, with Steels like these folks need to use diamond/CBN waterstones to get the best results.

Haven't tried Maxamet (yet) but in my experience, high carbide content super steels tend to cut better with a coarser edge -- no higher than 600 grit. You can get a polished edge but those don't seem to have the same "bite".

 

[Atama]

I received the Native 5 back from spyderco. Their representative called me when they had looked at the knife and told me a number of things that I could believe and some that I could not understand.

"maxamet does not like a fine mirrored edge." (my my pm2 and para 3 are ok with it)

He also said that because of the forced patina he could not replace the blade under warranty.

He offered to have the edge re sharpened and have the blade rockwell tested. He called back and said the rockwell came back ok.

I received the knife back with a good resharpened edge and it was sharp.

MY conclusions is that the ferric acid bath I subjected it to may have penetrated the edge and when I sharpened it , I did not remove enough material to get back to the more stable part of the edge steel. My pm2 and para 3 have not been taken into the ferric acid bath and therefore have not had that acid penetration.

Bravo and thank you to spyderco.

On other note. I did get it back with some bad side to side blade play. I contacted them about it they just told me to tighten the pivot and I did before contacting them. No resolution for that problem.

Hopefully this does help anyone wanting to force a full blade patina like i did. ( I did this with a k390 police and it sharpened perfectly well)

Interesting thought on the patina causing the issue. I have a ferric chloride forced patina on my para 3 and haven't experienced any adverse edge issues. It is also "near mirror" polished. Maybe I have sharpened it back to "good" steel?

It depends on the stones used, most folks are using alumina abrasive waterstones to get a higher finish on knives, with Steels like these folks need to use diamond/CBN waterstones to get the best results.

BBB KNOWS how to sharpen Maxamet. My Para 3 is hair whittling (ok, maybe just barely hair whittling, but still makes little trees, lol) , and I am nowhere near the sharpener BBB is (Disclosure: I started learning how to sharpen maxamet by watching his videos). Diamond/CBN is the key to great edges on this steel. I say this because I have not found it to be very difficult to sharpen with these stones, and have never had any of the edge chipping issues others have had on that steel. Downside is that diamond/CBN stones are spendy.

 

[wade7575]

Haven't tried Maxamet (yet) but in my experience, high carbide content super steels tend to cut better with a coarser edge -- no higher than 600 grit. You can get a polished edge but those don't seem to have the same "bite".

Before I knew any better I sharpened S110V with silicon carbide stones and aluminum oxide and polished edge's really sucked for sure,but with the metallic CBN stones and the Venev diamond stones I use the Venev 1200 which is the same as a 4K Jis stone and it takes and hold the edge way better then a higher grit edge with normal water stones.

 

[GABaus]

With the assistance of some of the experts here, I was able to get the edge on a Maxamet blade to an impressive degree of sharpness. I give it 30 degrees, and have been getting good performance out of it.

I don't let my edges get dull, and before I resharpen, I examine them closely to see what they're doing. As for the Maxamet, it behaves as I would expect. Most of my use is nothing special, envelopes, boxes, chopping and stripping medium sized wire, carving hard plastic. The damage I see before sharpening is nothing noteworthy. Wear is less than I would expect on other types of steel, and integrity of the apex is impressive.

Fast forward to earlier this week. I needed a chunk of something about 1/4" thick. I spotted some rubber floor mats in the corner that would be perfect. I whipped out the Maxamet blade and made two 4" slices through the rubber to make myself a square. The knife was hella sharp, and the ease at which the blade sliced through the material almost made me giddy.

When I was done, I wiped off the blade and carefully felt it. I was surprised to feel substantial damage. When I got home, I put it under the microscope and was very surprised at the actual extent of the damage.

Check out the attached pictures. Along the apex there were areas that were broken off. That was interesting, but not shocking, as I've previously observed Maxamet's propensity toward chipping. I was disappointed as it will take a little work to fix.

But what surprised me was areas along the flat part of the bevel, away from the apex, that appear to be spalled. That's really unexpected. And I was only cutting through rubber mat without a whole lot of pressure on the blade. I'm not sure what to make of this.

The rubber mat was soft and spongy, nothing out of the ordinary. I don't relish damaging a blade on purpose just for experimentation's sake, but this is so weird that I'm tempted to go back and grab a piece of the mat to bring home and examine closely.

You might have been unintentionally moving your blade side to side and since the medium was so soft it allowed the blade to move side to side putting more force than normal on the apex and since maxamet can be somewhat brittle the force on the apex was probably too much and it chipped. Not much you can do except sharpening at a slightly higher angle if this is the problem assuming you will be cutting more of this material.

 

[RustyIron]

You might have been unintentionally moving your blade side to side and since the medium was so soft it allowed the blade to move side to side putting more force than normal

Thanks for the feedback, GAB. I'm the original poster, and over the past six months I've learned a little bit more about Maxamet and other materials. In a nutshell, we all need to remember that this isn't Game of Thrones, we're not John Snow, and our knives are not made of Valerian Steel. I think that "forum hype" can lead us into believing that we can do crazy stuff with our super steel blades. That's not really the case. If we do stupid things with our knives, stupid things will happen.

I've since learned that this knife will maintain a really nice edge for a long time. But to be honest, I don't let it go a long time between sharpenings. I like to keep my knives near perfect, so they get touched up every couple weeks. Coincidentally, I just sharpened this Maxamet blade this evening. I was playing around, seeing how sharp I could get the knife using 250 grit diamond matrix. I got it VERY impressive, then gave it a couple strokes with some well-worn 40 micron paste on Roo Meat. Under the 'scope, the apex looks good, with scratches that would be expected, and chipping that can't be seen at this resolution, but I know it's there because of shadowing.

The moral of this tale is that no matter what phenomenon you're seeing, experiment long enough and you'll figure out a solution.

Thanks again!