Thread: Longer lasting edge?

Originally Posted by pfries

I agree with thebigspendur, Steel and technique foremost.
I would like to make a note, the angle of the finished bevel paired with the type of steel will have an impact on it.

I may be completely wrong but would a steeper angle produce a longer lasting edge over a shallower angle, hypothetically? (All things being as near to equal as possible)

Originally Posted by Christel

I may be completely wrong but would a steeper angle produce a longer lasting edge over a shallower angle, hypothetically? (All things being as near to equal as possible)

If I have garnered the information from looking at custom knives correctly there is a balance with steel type and angle for both taking and holding the edge.
Razors fall into a narrower breadth of angles but I would imagine it still plays a role.
If a steeper angle was all it took they would have eventually built them that way, I think the angle needs to be shallow to facilitate cutting the hairs effectively.

Again this is only my best semi educated guess and I hope to hear from some of our blade smiths with some input.

I think steel quality and the hardening process are the differences in the edge holding ability of razors. Having said that, I have observed that a burnished edge ( an edge that is very sharp and then polished a lot ) is more durable. I have had luck burnishing an edge with a translucent Arkansas, a Zulu grey, or a very fine Jnat using soapy water as a lubricant. It definitely increases the polish and keenness of the edge.

Originally Posted by Christel

I may be completely wrong but would a steeper angle produce a longer lasting edge over a shallower angle, hypothetically? (All things being as near to equal as possible)

you're right, there is a tradeoff here between a realy keen edge using a narow angle which is easily damaged and a wider angle I remember reading somewhere that for SRs the ideal angle is ~17 degrees, and most kitchen knives have an angle between 30 and 40 degrees for just this reason

I would say 100% down to the steel, as we often hear claims of old Iwasaki razors giving up over a 1000 shaves just with stropping before they need honing, after saying this those Iwasaki razors have a Rockwell of around 67 which would be way beyond any conventional modern razor, and It's not that hard to believe just look how sharp this Rockstead knife remains even after chopping into a bamboo I tell you now don't try this with your Sebenza or Spyderco as it will be blunt almost instantly. I think the Rockstead also as about the same Rockwell hardness as the Iwasaki razor.

According to Mr. Kousuke Iwasaki record, one of barbers had shaved 1032 people of beards without honing using just a leather strop when it became little bit dull. Many of other experienced barbers have also shaved over 900 people without honing.

I would kmagine that the most important thing is the steel, maybe 90% or more assuming that blade geometry, hardening, stress relieving, tempering and bevel formation are all perfect.

The next most important factors would be correct stropping and storage, in my opinion.

After that the frequency of use and the toughness of the wiskers.

But without doubt the last hone will play a part. Hones leave a progressively finer, and thus more attenuated and weaker edge past, say, 8k. At 16k, 20k and 30k you are giving the razor a very, very fine edge that is more susceptible to bending and deflection damage by the whiskers during shaving.

I think that the hones importance in edge longevity is undeniable. What is debatable is how much importance it plays in longevity - not much, in my opinion, other factors have far more importance.

As for word of mouth stories about fabled steels of yore, I am unconvinced. If I cant see it, hold it, experience it, if no one else can try it and it exists only in the minds of old timers and half mystical textbooks then in all probability it never existed.

Regards,
Neil