# Diamond Steels



## coulis-o (Jan 23, 2010)

i have recently switched from using an ordinary rounded sharpening steel to using an oval shaped diamond steel.

most of my professional chef knives are over a decade old and as a result of constant daily usage they have started to become more difficult to use and to sharpen, especially my G2 Global cooks knife which i use ALL the time so much so that i've sharpened it that much the blade is now warped towards the heel of the blade, but i still intend on using it because it is the knife i am most comfortable with, even though i have recently invested in a brand new dropped-forged global cooks knife that i could use and is a **** of a lot sharper

anyways i done rid of my old steel because it just wasn't sharpening my knife anymore, the new diamond steel works a treat though.


the thing with diamond steels though is first time i seen a chef using one they always used to put a coating of vegetable oil on the steel, and i am not one for following example without having researched things for myself. 

so first thing i did after buying a diamond steel is search the internet about the use of diamond steels, and i found many points against the use of oil on a diamond steel.

i can't think of anything positive why anyone would want to put oil on a diamond steel, all i can see it doing is reducing the effectiveness of it sharpening a knife


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## phatch (Mar 29, 2002)

A diamond sharpener does not benefit from oil. 

And a proper steel should not sharpen. it should not remove metal. It's a truing device, not an abrasive device.


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## homemadecook (Jan 27, 2010)

I've heard somewhere that putting oil in it is like sharpening it, and I guess that's the logic behind it.


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## discgolfjoe (Jan 9, 2010)

True, it's not shaving as a whetstone would, but more straightening the edge of the blade out. I don't think there would be any harm in adding oil to your steel, but if you are, I wouldn't use veg oil. I think you'd follow the same rule as a whetstone, and only use honing oil, because anything else would be absorbed by the pores in the stone (on a microscopic level) and sit there until it goes rancid, and stinks and makes it all gummy and useless.

Sorry about the run-on sentence...


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## boar_d_laze (Feb 13, 2008)

Your new oval, diamond sharpener is extremely coarse -- at least compared to a stone at the grit you should use for normal maintenance (i.e., sharpening before the knife is actually dull), and will eat your knives quickly.

I don't understand why 10 year old knives would become difficult to sharpen. Sharpened properly and as frequently as a professional environment requires, I'd expect them to be quite worn down. But difficult to sharpen, no.

_Problem no. 1:_ Bluntly, problem number one is most likely poor sharpening technique.

_Problem no. 2: _The nature of a "medium" or "coarse" steel. Oval or round, the contact point with the knife is so small that the steel exerts tremendous pressure along the length of the edge. Consequently, any irregularities in your sharpening technique are are greatly magnified -- as compared to bench stones.

People don't realize that steels require a certain amount of skill to use -- gentle, regular pressure; limited number of strokes; etc. It's not complicated, but it does require going to the troulbe of learning. But even then -- steels are much better for truing than sharpening.

_Problem No. 3:_ Again related to how steels work. Unless they're very aggressive, they don't so much sharpen (in terms of creating a narrow edge) as scuff up the old edge, and create micro-serrations. In the case of more aggressive steels, such as yours, those serrations aren't so micro. It turns the knife into a sort of saw with a coarse "set."

You get a knife which will "act sharp," rather than actually be sharp. Yes it will cut through a tomato; but it won't push cut well, and will tend to tear as it slices.

_Not a Problem no. 1:_ For your environment, needs and skills -- this, and all of this, simply may not matter to you.

Just like choosing the "best knife" there are very few absolutes in sharpening. If you like it, it doesn't matter what "experts" say. Just keep doing it. What the heck, they're 10 year old knives anyway.
_
Vegetable oil:_ Under no circumstances should you use cooking oil on your sharpening equipment. It goes rancid, smells bad and clogs or glazes stones, and clogs a rod hone's (steel's) grooves. In fact, the whole point of using oil at all is to prevent your rod hone from clogging. Using cooking oil as sharpening oil is a very common, rookie kitchen mistake and has destroyed many communal kitchen whetstones. Because a steel isn't as porous -- it's not a big deal. Just wash your steel with soap, hot water and a brush. Something you should do on a regular basis, anyway.

_Options: _ If you keep your steel clean, it won't need honing oil. If you don't keep your steel clean, it will need fresh honing oil every time you use it.

Soapy water works as well for sharpening as honing oil. For that matter, so does plain water. A clean, dry sharpener will cut quicker and more cleanly than a lubricated sharpener -- but will also need to be cleaned more frequently with soap, hot water and a brush.

I forget what passes for honing oil in Jolly Olde. Here in the states it's "mineral oil" which you can buy very inexpensively at any drug or hardware store. I understand it's sometimes avaialble under that name at UK chemist's but is quite dear. Another name for it is "petroleum oil," perhaps it's sold more cheaply under that name.

If you must use oil on your shaprening equipment, you can get by with unscented baby oil. Baby stuff tends to be sold at reasonable prices.

Good luck with your old knives,
BDL


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## indianwells (Jan 2, 2007)

I too have just replaced my old steel with one of the new oval ones. The name escapes me but it's German. I love it!


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## boar_d_laze (Feb 13, 2008)

F. Dick, possibly "Dickoron."

BDL


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## riverrun (Nov 14, 2001)

You said your favorite knife is a global, They are made out of titanium which will last forever but you need to purchase a special steel to sharpen them, normally i think it's made out of porclin because the steel is so hard.
And don't use oil on any steel.


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## phatch (Mar 29, 2002)

Titanium is softer than steel. Makes a terrible knife. Titanium knives have the edges set with carbides to do the actual cutting. And no, the globals are not titanium knives in general.

Titanium is stronger than steel by weight. Basically you can have a bigger lump of titanium than steel at the same weight. The same is true of balsa wood, stronger than steel by weight because you end up with so much balsa wood compared to the steel.

Balsa wood makes an even worse knife than titanium.


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## boar_d_laze (Feb 13, 2008)

Globals are not made out of titanium. They are made from a stainless alloy called CroMoVa18, made expressly for Yoshikin (Global's parent company). It's interesting in the limited sense of being extremely stainless by virtue of the high percentage of chromium, yet Global coaxes adequate edge qualities from it. Given the amount of chromium, you'd expect it to behave more like 420J2 or "dive knife" steel. Corrosion resistance aside, CroMoVa18 is on the low end of the performance spectrum for alloys used in similarly priced, Japanese made knives. Adequate, but barely adequate.

Globals are not particularly hard, either. Yoshikin advertises them at 56 - 58 on the Rockwell C scale. It's nothing to sneer at, but nothing to write home about either. Also, experience has shown that manufacturers tend to be very optimistic in their Rockwell numbers, so 56HRC is probably a lot closer than 57 or 58.

Globals do not last forever. They actually wear fairly fast.

You don't need to use a _porclin_ [sic] or any other sort of ceramic hone. (Not that there aren't some wonderful ceramic hones, but that's another subject.) For one thing, most of what a rod does it accomplishes with mass, rather than hardness. Second, as long as the rod is sufficiently hard so that a poorly angled knife can't cut into it -- it's hard enough.

There is simply no reason you can't use a good, oval steel -- as long as you don't care too much about edge quality or wear rate.

BDL


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## coulis-o (Jan 23, 2010)

true that Global knives aren't made out of titanium they are made from molybdenum vanadium steel.

the steel i had before i bought from a car boot sale for 50pence (cheap i know, but i put money into buying a decent steel this time around) i've had it since i started catering college, it isn't a coarse steel but it no longer seems to be truing the knives i use the most, the difference with using the diamond steel is great and easily noticeable.

the knives i have are mostly 10 years old and that probably equates to the lack of care i tend to give to them nowadays. i bought a new chefs knife and i am afraid to use it like i do my other knives, i do use my knives constantly on a day to day basis though, they go through and take a lot of sh!t both during service and prep.

good point BDL raised about washing/cleaning a steel something i've never done for fear of a steel possibly rusting


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## itsnotburned (Sep 23, 2010)

I just washed my steel for the first time in my life and it looks, and works much better. I was actually considering buying a new one. I don't know why it never occurred to me before, seems like the most practical, common sense thing in the world. Anyway, just wanted to say thanks for the thread and all the great information.


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## halmstad (May 17, 2010)

i always thought, not an educated thought, that not washing a steel would be the same as not washing away the mud created sharpening on a whetstone. 

this is a great thread. the more info the better.

i'll be washing my steels in the am.


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