# Did I just ruin my knife?



## sepandee (Oct 4, 2016)

I have a Global G-46 7cm/18" stainless steal knife: https://www.amazon.com/dp/B0006A03QA/?tag=skimlinks_replacement-20

Been meaning to get it sharpened. I happened to come across a knife and tool sharpening truck, sort of like one of those ice cream trucks with the bell, passing through my neighborhood. Asked the guy if he sharpens with stones and oil, and he said yes. Great. Just saw him today again passing by my house, gave him the knife, and went to grab my wallet. When I came down, I saw him sharpening on one of these... i don't know what to call them, these round stones that rotate really fast, and their were sparks coming from the sharpening (sort of like the ones you see on this picture in the middle of ta




).

The knife cuts through paper again, but have I ruined/damaged my knife permanently? Maybe this is how you sharpen a knife, but it's not what I was expecting. I was imagining the stone and oil method.


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## cheflivengood (Oct 4, 2016)

Your edge might now be slightly hollow but thats not the worst thing to ever happen to a global. And just for further education, quality stone sharpening is done with water, not oil.


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## alterwisser (Oct 4, 2016)

First of all: it's a Global! Relax!

It cuts, right? You're fine. And it's hard to permanently ruin a knife. 

A higher end Japanese knife, you don't want to see that sharpened this way. But a lot of "professional" sharpeners you see driving around, setting up shop in supermarkets and such, they sharpen like "your" dude. It's not great, but it's perfectly fine for cheap stainless knives IMHO

There are others in this forum who can give you a much more sophisticated answer, of course [emoji6]


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## sepandee (Oct 4, 2016)

alterwisser said:


> First of all: it's a Global! Relax!
> 
> It cuts, right? You're fine. And it's hard to permanently ruin a knife.
> 
> ...



Thanks! I know it's a global, but for most of us mortals and commoners who aren't too obsessed with knives, it's more like "it's a global? Wow." Probably cost $80-$100, which is pretty close to what I plan to ever spend on one single knife.


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## cheflivengood (Oct 4, 2016)

sepandee said:


> $100, which is pretty close to what I plan to ever spend on one single knife.



lol you better get out of here, or that wont last long.


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## Mucho Bocho (Oct 4, 2016)

If that's the case, it was good to know you and thanks for the story. 

Just know you that don't have to be a knife nut to experience the thrill of a properly ground knife with proven profile and good HT. It's a cooks simple pleasure that most will never know.


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## alterwisser (Oct 4, 2016)

sepandee said:


> Thanks! I know it's a global, but for most of us mortals and commoners who aren't too obsessed with knives, it's more like "it's a global? Wow." Probably cost $80-$100, which is pretty close to what I plan to ever spend on one single knife.



I'm just busting your chops man. If you come here posting about a Global, you gotta be able to take some of that LOL

Next time you buy a new knife for $80-$100, come here first and we'll give you recommendations that blow your Global out of the water [emoji6]


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## alterwisser (Oct 4, 2016)

cheflivengood said:


> lol you better get out of here, or that wont last long.



LOL


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## Obsidiank (Oct 4, 2016)

Globals are single pieces of metal with a convex grind. 

Worst case the sharpener has changed the factory grind or bevel angle. 

If it cuts well I would not worry too much about it. 

http://www.memagnus.com/wp/?p=306

https://en.m.wikipedia.org/wiki/Grind#/editor/2

I don't waste time sharpening my globals with stones. They get sent in batch for wheel grinding.


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## AllanP (Oct 4, 2016)

You can get an edge sharp with anything that removes metal, you can **** up your knives with stones too if you don't know what you are doing.
Pictures of the knife would help, I mean if he just gave it a new primary bevel and it cuts paper fine, I don't really see a huge problem.

I am not familiar with sharpening with grinders, maybe if sparks come out it might have heated the knife too much, maybe he took too much metal off the blade by using a grinder vs stone which is slower.


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## ThEoRy (Oct 4, 2016)

If he took too much metal off of it the geometry will be thicker near the edge. While it may be sharp enough to cut properly now, what will happen as the knife dulls? It may not perform like it should. In addition, the Global knives that I've owned all came with factory recommendations of a 70/30 asymmetrically sharpened edge. If your guy doesn't know that, he could have put a 50/50 edge on it. Again, it may be sharp but it may not perform correctly. Wedging, steering issues could arise.


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## spoiledbroth (Oct 4, 2016)

I think people should chill their attitudes a bit. Like op said global is high end to most of the world. What's more that kind of elitism regarding knives does not serve anyone in this community. Compared to a wustie a global is most definitely a great knife. 

Cheers.


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## milkbaby (Oct 4, 2016)

To be honest, he probably just did what the average knife sharpening service does which is running it on a bench grinder. It it works okay, you're probably good to go, just use it and see.

The crowd here is tough since many people have really REALLY nice knives. It's like driving up in a Nissan Z to a gathering of Ferrari owners or something.


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## spoiledbroth (Oct 4, 2016)

For what it's worth the original poster's thoughts are correct this is not the greatest way to sharpen a knife and it can affect the heat treatment. That being said as another person commented here you will find mostly users of Japanese type Waterstones which unlike the kind of stone the original poster is thinking of use water for lubrication.


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## DanHumphrey (Oct 4, 2016)

I have a bit of a thing about "Global" particularly because a friend of mine insists they're the best and I'm a fool for not just getting a stack of them instead of what I do have.


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## alterwisser (Oct 4, 2016)

DanHumphrey said:


> I have a bit of a thing about "Global" particularly because a friend of mine insists they're the best and I'm a fool for not just getting a stack of them instead of what I do have.



Guess we're all fools


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## daveb (Oct 4, 2016)

If memory serves our own Dave Martell started with a truck like this, though I think he used a bicycle thingy with belts.


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## panda (Oct 4, 2016)

i use a global at home, and havent sharpened it in 3 months


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## DanHumphrey (Oct 4, 2016)

alterwisser said:


> Guess we're all fools



In fairness, I could've bought my Tanaka, my combo stone, and called it a day. Not like dinner is cooked any better or quicker with my Dalman. Or NuForgecraft.


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## brainsausage (Oct 5, 2016)

I've seen sparks coming offa them high falutin water wheels the so called pros use. If it gets a good edge and doesn't screw up the knife, does it really matter how it got there?


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## LifeByA1000Cuts (Oct 5, 2016)

A geometry dependent on a 70/30 edge is not that likely, given that Global endorse at least one line of pull through sharpeners that do not seem asymmetric.

Affecting the HT with a sparks-flying bench grinder is likely a real risk though - "keep cool!" indeed, that is what the sharpener should have done.

BTW, using oil (as opposed to water) on benchstones seems to be generally considered a viable but outmoded, old school method around here.


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## Lars (Oct 5, 2016)

Anyone who gets their knife sharpened is on the right track imo.
That was what got me into this wonderful hobby. Having a knife sharpened and being unhappy with the results.
Turned out my heirloom stainless sabatier was best suited as a display item.
Started to investigate, found the old forum and have been hooked since.

Lars


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## ThEoRy (Oct 5, 2016)

LifeByA1000Cuts said:


> A geometry dependent on a 70/30 edge is not that likely, given that Global endorse at least one line of pull through sharpeners that do not seem asymmetric.
> 
> Affecting the HT with a sparks-flying bench grinder is likely a real risk though - "keep cool!" indeed, that is what the sharpener should have done.
> 
> BTW, using oil (as opposed to water) on benchstones seems to be generally considered a viable but outmoded, old school method around here.



If you are saying it is not likely Globals are not to be sharpened 70/30 you are mistaken. In the literature that came with my Global knives it very clearly stated to sharpen them 70/30.


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## LifeByA1000Cuts (Oct 5, 2016)

I meant "will work best 70/30" vs "will work terribly at 50/50 due to a fundamentally asymmetric geometry" ...


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## johndavid (Oct 8, 2016)

I will disagree with the general consensus of the majority of replies. I hope I don't offend. 

If the guy was 'sharpening' you knife with a rotary disk grinder - then yes the temper on your knife very well could be damaged. 

Yes - professionals, typically in Japan, use large rotating stones but they usually have a water source flowing and some type of splatter guard because it's messy. This guy doesnt, he doesnt even have a water container like you would find a on tormek. 

My thoughts? Disk grinders and automated machinery risk heating up a knife to the point to where the temper is ruined. It may cut, but the metal may not stay sharp for very long.


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## Bloum (Oct 9, 2016)

You may be right @JohnDavid, but in this case, the grind sould have tinted in a blue-ish color, you can't miss it


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## JBroida (Oct 9, 2016)

Bloum said:


> You may be right @JohnDavid, but in this case, the grind sould have tinted in a blue-ish color, you can't miss it



Not necessarily... Especially if he buffed after the grinding


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## Kippington (Oct 9, 2016)

JBroida said:


> Not necessarily... Especially if he buffed after the grinding



Very true. The color change only affects the surface steel.
You can grind off any evidence of overheating and no-one would be the wiser...


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## Bloum (Oct 9, 2016)

I learn something today, thanks both of you :thankyou2:


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## LifeByA1000Cuts (Oct 9, 2016)

I guess the big confusion arises from pictures and footage of knife makers using sparks-flying bench and belt grinders....

...either before final HT or to roughly shape things post-HT before still grinding the damaged steel off in the final steps...


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## Marek07 (Oct 16, 2016)

I've owned some Globals for over 12 years. I have never heard of a 70/30 grind on them. I searched their Australian and International websites and can see no mention of this asymmetry nor do I recall any accompanying literature mentioning this. I even spoke to the Australian distributor who was only able to say that the knives were set at 15 on both sides.

I note that some very experienced members have stated that Globals are asymmetrical - so what have I been missing? It could be that I've just not realised and sharpened incorrectly for all this time. Any insights are welcomed.


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## ThEoRy (Oct 17, 2016)

Marek07 said:


> I've owned some Globals for over 12 years. I have never heard of a 70/30 grind on them. I searched their Australian and International websites and can see no mention of this asymmetry nor do I recall any accompanying literature mentioning this. I even spoke to the Australian distributor who was only able to say that the knives were set at 15 on both sides.
> 
> I note that some very experienced members have stated that Globals are asymmetrical - so what have I been missing? It could be that I've just not realised and sharpened incorrectly for all this time. Any insights are welcomed.



Welp, if you won't take my word for it perhaps you would listen to this guy. "Mr. Global"

[video=youtube;SIw5ChGOADE]https://www.youtube.com/watch?v=SIw5ChGOADE[/video]


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## Marek07 (Oct 17, 2016)

ThEoRy said:


> Welp, if you won't take my word for it perhaps you would listen to this guy. "Mr. Global"
> 
> [video=youtube;SIw5ChGOADE]https://www.youtube.com/watch?v=SIw5ChGOADE[/video]



Thanks for the link Rick. It was actually your post that got me looking for the Global asymmetry - just couldn't find it. Looks as though I've ground down all my Globals to a 50/50 profile over years of inattentive/poor sharpening.


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## jaknil (Oct 17, 2016)

When you look at the chart in the video (eg at 0:54) it is clear that the one on the left is ground symetrically with a 10 or 15 degree angle.
The only mystery is why it says 70/30 under the drawing.
It becomes even more confusing to explain the middle drawing with the 80/20 text. 

I don´t see the video as a confirmation of the fact, that global should be ground asymmetrically.
He does not mention this at any point. 
He only argues that the primary bevel should be bigger than "western style".


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## Benuser (Oct 20, 2016)

Larger bevel = lower angle 
If you follow the blade's geometry you certainly end up with a strongly convexed right bevel. As the edge is slightly off-centered to the left, I'd put a small straight bevel at a high angle on the left side to compensate for steering. 
Problem with brand new Globals is there's almost no visible bevel. Both sides very convexed. They can benefit from some serious thinning.


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## fatboylim (Oct 28, 2016)

I have an old Global that was hollow ground using a wheel. It is much sharper with less convex issues; so an improvement really. Note, the hollow grind makes a more delicate edge and can chip more easily. It may change the uses of the knife.


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## Benuser (Oct 28, 2016)

I hope it's not really a concave edge. It wouldn't hold on the board.


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