Thread: That shaped hone...

Yes the convex hone. Not really about the hone itself but I know that some are skeptical of the historicity of the claim. I was pointed to a text which would seem to verify that the idea was around and in use in Germany at least around the 1850's. This says nothing of it's use before or since.

In addition to this there are some more paragraphs in other publications I am working on translating out but it will take a little time.

The book is called Polytechnische Mittheilungen published in 1846, Volume 3. It is available to view on Google Books and anyone can verify my translation for themselves.

https://www.google.com/books/edition...C?hl=en&gbpv=1

The important text is on page 29.

The practical effects of the hone are not important for this thread, I don't want it to degenerate like the last one, I just wanted to share that there is at least some kind of evidence of it being 'a thing', enough of a thing that a German journal for technical colleges would document it.

I'm researching more out of my own sheer curiosity as to where the idea came from and how far it went. If anyone has any historical documentation of the idea feel free to post. Let's just keep this about the history of a certain idea and stay away from the practicalities of honing. Onto the translation:

In English:

"the stone intended for sharpening the razor must be hard, with a very fine, uniform and dense grain, because without these properties it can never produce a properly fine cutting edge.

some apply two or three stones of gradually increasing fineness of the korus one after the other; It is certain, however, that you can always achieve your goal on a single, very fine stone - perhaps with a little more expenditure of time - probably even to the advantage of the cutting edge, because you do not expose yourself to the need to first work through the roughness caused by the rough stone to devour the finer.

Others go even further by giving the successive stones a different shape. In particular, an experienced man praised the following procedure as being very beneficial: the first, sharpest stone (which can be an oil or a water stone) should be given a convex shape; just like that, but to a lesser extent, the second, who is a Levantic oelstein; only the third (last) stone has to be completely flat, and for this you choose a fine, hard slate of clay (blue whetstone) on which you always have to pull it off with water.

this method is efficient; because through the convexity of the first two whetstones it causes a successive thinning of the knife in the vicinity of the cutting edge, consequently means that at the end of the day the flat stone only produces exceptionally narrow facets and its work is completed quickly: I only believe that the machining on the convex stones will require even more skill than honing the already difficult task on a flat stone. In fact, as far as I know, the latter is found exclusively in use by knife manufacturers, knife sharpeners and barbers. "

In German:

"der zum abziehen der rasiermesser bestimmte stein muss hart, dabei vou sehr feinem gleichformigen und dichten korne sein, weil er ohne diese eingenschaften niemals eine gehorig feine schneide zu erzeugen vermag.

manche wenden zwei oder drei steine vou stufenweise zunehmender feinheit des korus nach einander an; es ist aber gewiss, dass man auf einem einzigen ganz feine stein - vielleicht mit etwas mehr zeitaufwand - jederzeit zum ziele kommt, wohl sogar zum vortheil der schneide , weil man sich micht der nothwendigkeit aussetz, die von dem grobern steine verursachten rauhigkeiten erst wieder durch den feinern zu vertilgen.

andere gehen noch weiter, indem sie den auf einander folgenden steinen auch eine verschiedene gestalt geben. namentlich ist mir von einem ertahrenen manne folgendes verfahren als sehr vortheilhaft geruhmt worden: man soll dem ersten, scharfsten steine (weicher ein oel-oder ein wasserstein sein kaun) eine konvex-gekrummte gestalt geben; eben so, jedoch in minderem grade, dem zweiten, der ein levantischer oelstein ist; nur der dritte (letze) stein musse gauz eben sein, und hierzu wahle man einen feinen harten thonschiefer (blauen schleifstein) auf dem das abziehen stets mit wasser zu geschehen hat.

rationell ist diese methode; denn sie bewirkt durch die konvexitat der ersten beiden abziehsteine eine successive verdunnuug des messers in der nahe der schneide, macht folglich, dass zuletz der flache stein nur ausserat schmale facetten hervorbringt und seine arbeit schnell vollendet: ich glaube nur, dass die bearbeitung auf den konvexen steinen noch mehr geschicklichkeit erforden wird, als das schon gennngsam schwierige abziehen auf einem flachen steine. in der that findet man den letztern, so viel mir bekannt, ausschliesslich im gebrauch bei den messerfabrikauten, messerschleifern und barbieren."

In the end its still finishing on a flat stone. I had no idea this type of honing was done that long ago. Thanks for looking it up.

A convex stone partly reduces the need for lapping/reshaping.

If a honer hones all day for a living, taking out the need for flatness on the lower grit stones would be a plus and saves money.

A former member said a stone would normally last for 2000 blades. If a convex stone hones 3000 or 4000 blades your profit margin is increased.

Me thinks that we will get a response very soon from someone who is trying to sound (not very well btw) like hes german and english is his second language.

Originally Posted by rolodave

A convex stone partly reduces the need for lapping/reshaping.

You are mistaken; the reference to a shape and its accuracy is just as important.

It's just a different shape.

A curve with a flat portion will offer a razor just as much degradation as a flat hone with a concave portion. You need as consistent a shape as possible, and the smaller the shape of the wheel the more concave becomes the cutting edge and the more skill required of its administrator.

The technical manual makes no mention of speed issues, in fact [in German] it openly concedes what is best, but advises to leave what is best to those who are best at doing it.

Gasman, it is "still finishing upon a flat stone" as you say, but only following so much concavity been imparted to the bevel plane itself from the prior wheel shaped stones that the concession in thinness the flat stone necessarily introduces(introduce and not "reintroduce" is the correct English as no prior abrasive field was flat) is of less importance. Is that how you use your own flat stones, by first concaving the bevel with wheel shaped hones and then topping off the terminus with the file?

What is a producer to do when an end user populace tells them they are producing their own production item (often having been produced continuously over 100yrs in a single factory location) incorrectly? Should they reinvent as the Scots did the chill filtration, or go the French brandy route and tell them take it or leave it? What is a producer to do knowing when a venue dedicated to the concept's production's senior moderator will awaken in hours and immediately render the conversation to a different path (catered to their need to have never made an incorrect assumption)?

Good morning Jarrod!

Originally Posted by Bill31521

Me thinks that we will get a response very soon from someone who is trying to sound (not very well btw) like hes german and english is his second language.

My English may be more formal but it is correct syntax; if you are having trouble understanding it is due to local dialect and not formal English.

One can imagine that Solingen producers can never identify by name in this venue and be treated with respect.

In any case you all have read the information now, what you do with it is up to you and if you insist to have thicker cutting edges you have indeed already purchased the tool. Please do examine the advanced subsection herewith, where concepts such as deliberately thickening the cutting edge ( in the complete inverse of what productions aim to achieve ) is embraced!

Originally Posted by razorfranken81

You are mistaken; the reference to a shape and its accuracy is just as important.

It's just a different shape.

A curve with a flat portion will offer a razor just as much degradation as a flat hone with a concave portion. You need as consistent a shape as possible, and the smaller the shape of the wheel the more concave becomes the cutting edge and the more skill required of its administrator.

The technical manual makes no mention of speed issues, in fact [in German] it openly concedes what is best, but advises to leave what is best to those who are best at doing it.

Gasman, it is "still finishing upon a flat stone" as you say, but only following so much concavity been imparted to the bevel plane itself from the prior wheel shaped stones that the concession in thinness the flat stone necessarily introduces(introduce and not "reintroduce" is the correct English as no prior abrasive field was flat) is of less importance. Is that how you use your own flat stones, by first concaving the bevel with wheel shaped hones and then topping off the terminus with the file?

What is a producer to do when an end user populace tells them they are producing their own production item (often having been produced continuously over 100yrs in a single factory location) incorrectly? Should they reinvent as the Scots did the chill filtration, or go the French brandy route and tell them take it or leave it? What is a producer to do knowing when a venue dedicated to the concept's production's senior moderator will awaken in hours and immediately render the conversation to a different path (catered to their need to have never made an incorrect assumption)?

Originally Posted by Bill31521

Me thinks that we will get a response very soon from someone who is trying to sound (not very well btw) like hes german and english is his second language.

Wow Bill, you can see into the future! Do you mind letting me know this weeks lotto numbers

Ive heard this argument so many times before. You have never proven the benefit of rounding off my flat stones.

A large part of the discussion around the convex hone has been quite unfortunate imo.

First you have the historicity of the idea itself, which I never really doubted, but I can see how some would as when asked for direct evidence Jarrod (let us address the man directly) would for the most part just allude to old grinding manuals, old books and pretty much just tell the skeptics to go do their own research. This is an inappropriate attitude to have when advocating for a position. I actually got into a discussion about this on YouTube with him, he would again just allude to the idea then when I pushed him hard enough to back up his claim he would then come back at me with some names of writers, or the name of a book, and when I checked them out they were legitimate.

Jarrod would have been much better served by, when learning about the convex hone, coming to the forum and writing a thorough, informative post, translating out the German like I am attempting to do, and being more lighthearted about the matter. Imagine if this whole thing had started out with a thread something like:

'Hey guys, Dovo told me about this convex stone they use, they said it goes way back. I looked up a whole bunch of old technical manuals and grinding documents and translated them out of German, take a look yourselves at these links, might improve our edges".

Maybe I am wrong but it doesn't seem he did that, but I think the idea would be more amenable to some had he.

Something else that didn't help him was this kind of insistence that the only real way to 'skin the cat' was the convex stone, that it is the only true way lest you pretty much ruin your razor. Now maybe the grinders in Germany would prefer users to maintain the factory geometry but they've never provided any tools to do such. We also have the fact that most people have used a flat or relatively flat hone to keep their razors in shape with no ill effects to the razor, or to the comfort of the shave. Now maybe, in theory, the convex would be preferable, it's just a pointless thing to be so assertive over. Insinuating that a substantial portion of razor honers are pretty much cognitive peasants for not immediately recognizing the 'superiority' of the convex hone isn't going to make people amenable to hearing you out, rightly or wrongly.

I think it's fair to give Jarrod his due for bringing to our attention a historic method of honing that could infer some advantage to the end user in the modern day. Some people have insinuated he pretty much made the whole thing up, or Dovo made it up to cover for recent production woes in regards to grinds/honing. This is obviously untrue and for such an accusation to stand would not be just.

The man is obviously passionate about the industry and the history of razors and their manufacture.

I'll try have another post up later today with a translation I found in a German Microscopy journal.

Keep it light everyone.