Which type/brand of razor blades stay sharp longest? (cutting card/greyboard)

Carbide is a bit of a catch all term. There are as many carbides as there are metals which will make them.

-Danger massive simplification ahead-

Tooling carbide is usually a powder metallurgy product, where small grains of tungsten carbide are held in a cobalt binder matrix. As a result there is a limit to how sharp an edge it will take - think of it like raisins in a fruit cake - you can’t slice as fine a slice as of a plain sponge. The raisins prevent it.(Not a very good illustration but possibly sufficient)

More expensive carbides are called Micrograin, and take a sharper edge because the grains are smaller...

The main advantage is that carbide is very wear resistant, so the not very sharp edge stays not very sharp longer than the sharper but less wear resistant sponge cake. If the sharp edge is ‘sufficiently sharp’ that’s a win overall.

Metal cutting tools don’t generally need to be that sharp (it’s a relative term), but they do need to be wear resistant.

Is that because 'graded grains make finer flour carbide' ?

Sorry...
DaveD
Probably an age-related advert thing.

Yes, interesting about carbides being a power metallurgy product.

Either way Stanley seem to have created damned sharp carbide blades, which I am currently testing.

So modern safety/disposable razor blades are just make out of some kind of stainless steel? Do we assume that their sharp edges are created by grinding them down... e.g. with diamonds?

IIRC they are stamped (blanked) out of thin stock in a long continuous chain, then run past a pair of normal wheels in a fairly continuous process. I’m sure YouTube will have a video.

no need for diamonds, AlOx will do fine

A slight digression [hopefully John has no objection] ...

There was a fad in the 1970s for ‘sharpening’ razor blades by ‘Pyramid Power”

... debunked ... but with one useful outcome

I always flip the blade in my safety razor after each shave

**LINK**

https://www.newscientist.com/lastword/mg23531441-500-lets-be-blunt/

MichaelG.

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P.S. __ Whilst obviously not appropriate for cutting board: Merkur blades are the best I have used.

Too late to edit ^^^

**LINK** : https://www.dovo.com/en/about-us/

Blades are variously labelled as Dovo, Merkur, and Shavette

... presumably branded for different markets.

MichaelG.

>>>
My dad used to work for a large razor blade manufacturer. He told me that the firm had done tests showing that by alternating blades, more clean shaves could be completed per razor than if you used the same blade every day.

He said this was why expensive cutthroat razors came in sets of seven – and why using a “magic pyramid” (popular in the 1970s), whereby a razor blade was placed under the pyramid for a few days and apparently resharpened itself, seemed to work
>>>

This is rather extraordinary. So razor manufacturers seem to be saying that razor blades are actually sharpening by themselves! Does anyone know how this works?

What I do know is that [Alert: Top Top coming!] you can get vastly more life out of a razor blade if you soften the beard first. One way to do this is by having shower beforehand - certainly helps - but simply leaving the shaving foam on whilst you brush your teeth you get a much smoother shave and the blades will last very longer.

J

Just to clarify the edge-turning business with razor blades:

Here is a well-used DOVO blade ... the shiny bit is where the ultimate edge is turned up towards the camera, and is catching the light.

Regular flipping of the blade can reverse all but the worst of such bending ...

Bad bits like this are what prompts one to change the blade !

The photo represents a 2mm length of the blade.

MichaelG.

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