Super Hard (70 Rc) High Speed Steels – Maxamet, Rex 121, and More Explained

[Rhinoknives1]

Thanks for good explanation and understanding!

Totally agree with the preference. I am new to the knife world, but I found myself by default had a mindset that kitchen knives are just a different thing from the knives I am going to put in my collections... (I still don't know how that happened.) My impression is that the couple steel and ceramic knives in the kitchen work just fine. Rarely needed to sharpen, but maybe like you said they are already horribly dull by other standards... I only recently realized the potential damage issues with dishwasher, and I am surprised that our kitchen knives hold up fine (by our standard) with their trips in the dishwasher. Never noticed rusts at least... I don't even know the steel type and couldn't find it in addition to just stainless. Maybe it's not important or cared by ordinary people (like myself couple months ago), so the producer don't even care to put it on.

Speaking of the trade off, I guess the technology hasn't been developed to the point to give knife makers the option of keeping edge performance while dishwasher safe.
Technical innovations have freed people from many repeated tasks, dishwasher is one of them. I don't think kitchen knifes are destined to be excluded. The fact that enough people have done that destroying their knifes seems to suggest a market for dishwasher safe knives (or maybe knife safe dishwashers). I hope in the near future, the new materials can free knife makers from trading one off another.

You can make poly etc plastic handles that can withstand DW & detergents and there are are Steels that can handle the hot water . the problem is the detergent used in dishwashers is caustic. It eats the food off of the plates & it’s strong enough to Frost the edge of your knives. Making them brittle. ——- I can by looking without a magnifying glass tell when a customers knives have repeatedly been run through a DW & with a glass after only 2-3 washings. ————In restaurants etc here in California the knives are suppose to be run through a DW with a sanitizer fluid. They have to. You don’t , just hand was your knives & carbon steel ones, dry over an open flame like is done with cast iron. Only a bit further from the flame...

 

[Larrin]

Dishes also tend to whack into each other in the dishwasher which isn't good for edges.

 

[superpog]

If you're using the dishwasher your knives can never be this sharp. To make them hold up to the dishwasher this amount of performance MUST be reduced.
It's not a technology thing just the limits of things. Maybe in 100 years when the make a knife out of nanobots...wait might short circuit in the Hyperwasher. Oh well.

OK, so this is completely above the level of sharpness I was thinking. In my kitchen, I still use pull through sharpeners which I believe will never get even close to this sharp... And I agree the knife needs to be treated very carefully to keep this performance

 

[superpog]

You can make poly etc plastic handles that can withstand DW & detergents and there are are Steels that can handle the hot water . the problem is the detergent used in dishwashers is caustic. It eats the food off of the plates & it’s strong enough to Frost the edge of your knives. Making them brittle. ——- I can by looking without a magnifying glass tell when a customers knives have repeatedly been run through a DW & with a glass after only 2-3 washings. ————In restaurants etc here in California the knives are suppose to be run through a DW with a sanitizer fluid. They have to. You don’t , just hand was your knives & carbon steel ones, dry over an open flame like is done with cast iron. Only a bit further from the flame...

Good to know the chemical effects!
My kitchen knives are some $30 a set from market, so I don't think I want hand-wash and dry them over an open flame... I will if I decide to get some high quality kitchen knives in the future. I will also treat my collections well, they will never get into a DW.

 

[superpog]

Toughness can be normalized by the width*thickness so it becomes J/cm^2. However differences in thickness change the behavior because the surface is always more ductile so the thinner it is the greater the percentage of the thickness is affected by the surface. You can read more here: https://www.nde-ed.org/EducationRes...ge/Materials/Mechanical/FractureToughness.htm

Hi Larrin, I have another toughness data question. In the table you have some data points obviously outside the graph like 3V and 1095 at lower hardness. I wonder if you are willing to share those data. For steel like 1095, the knives from the manufacture are usually targeting lower hardness, I would love to know what is the toughness data looks like at that range. Thanks!

 

[MolokaiRider]

Another good read, thanks for sharing.

Taco Bell did not have any Vasco Supreme in stock.

I need to try out Maxamet, the more I read about it the more intriguing it gets.

 

[Larrin]

Hi Larrin, I have another toughness data question. In the table you have some data points obviously outside the graph like 3V and 1095 at lower hardness. I wonder if you are willing to share those data. For steel like 1095, the knives from the manufacture are usually targeting lower hardness, I would love to know what is the toughness data looks like at that range. Thanks!

Who are these manufacturers making low hardness 1095 knives? Switch to 1050. The toughness doesn’t get much better at low hardness. Needs a lower carbon content.

 

[superpog]

Who are these manufacturers making low hardness 1095 knives? Switch to 1050. The toughness doesn’t get much better at low hardness. Needs a lower carbon content.

Tops and ka-bar’s 1095 are 56-58
ESEE is 55-57 according to data from bladehq.

Your graph cuts at 58, it looks linear for 1095, the projection is around 13 to 14 ft-lb at 55RC?

 

[Larrin]

Tops and ka-bar’s 1095 are 56-58
ESEE is 55-57 according to data from bladehq.

Your graph cuts at 58, it looks linear for 1095, the projection is around 13 to 14 ft-lb at 55RC?

That's an older chart. Here is a newer one from the Nitro-V article:

 

[superpog]

That's an older chart. Here is a newer one from the Nitro-V article:

Cool, thanks!