Thread: Dovo’s honing method

Originally Posted by thp001

I was making the point that most edge tools were always traditionally ground towards convexity, which may or may not have informed past peoples ideas about ideal edge bevel geometry on other, more specialized cutting tools, ie, razors.

Not following your logic on that at all

SR's have been hollow ground since the 1700's their bevels have always been honed and stroped toward a convex bevel and edge

Maybe I am just missing your point

Originally Posted by razorfranken81

hello

you may wish to read sentence four of paragraph two of page 12 of this (sorry this link but I cannot find otherwise in English, this is the only time I am aware it was written published in English since last 100 years);

https://www.yumpu.com/en/document/re...a-edition-2020

Hello
I'm not sure if you're trolling or we have a language problem but your post seems very confused.

I read the whole page on your link rather than one sentence & it is a description of making a bellied hollow grind. All hollow ground razors are made this way to varying degrees.
This has nothing to do with the shape of the edge bevel.

In fact all razors are concave in grind ,even wedge razors ground on a 36" wheel must be slightly concave.

Once you put a razor on a honing stone, only two points of contact will be made, the edge and the spine.
The distance between two points is a always a straight line. Essentially this will create an isosceles triangle... at the bevel. It's simple geometry.

Even if a hone were convexed lengthways rather than side to side the resulting concavity of the bevel would be irrelevant in real world use.

So, here is a simple question and solution. How many of the “Shave Ready Machine experts, shave daily with one of your razors?

Find someone in your organization that does and ask him how he hones his razor.
While the machine may measure the accuracy of the grind, it still must be honed. Even a poorly ground Dovo or even a Chinese Gold Dollar can be made to shave well.

You are missing the point or being sold a bill of goods. Either learn to hone a razor or stop telling people that the razors are shave ready, if you tried to shave with one, you would know.

hello again

I do not know what to say to the idea that a 17-20cm finishing wheel [standard for approximately 1890-1930] would leave a curved cutting edge profile that varied from an isosceles triangle edge profile 'by microns' or that you would not feel the difference. Have you experts shaved from a 20cm finishing wheel? If so, where did such a wheel exist? It is possible no person alive has had this deceased standard. Why did all the manufacturers use this as their ending at the height of hollow grind razor productions, never a flat stone, while owning both tools (the flat kept for wedge grind sharpening) in the factories, just to push production? Are you aware of how low the adjusted price for honing was at the time thanks to no labor laws against women and children at height of Industrial Revolution?

Certainly we agree a line separates two points, but if the points on the line were only moving in reference to one another while upon any arc, the metal represented by the boundary aside their motion will be a curved boundary.

All will work out once the certificates start coming with the razors, you will then essentially be demanding the end of production, which has come perilously close before and could happen again, but at least you will need to state such demand in objective terms as referenced by the testing data.

It is a strange phenomenon indeed that the most senior experts on a self instructed forum demand excellence that today even Wacker (= one very small work-kottage) does not meet the standards, I wish for you the time of highest production, and quality, where you can take the very best of Victorian hollow grinding excellence without humanity's prior consumption of that steel interfering with the supreme quality required (and at this time you can erase the incumbent cutting edge, just 10cm reference for the best razors of the period, with the preferred convex or isosceles edge shape).

Germans do occasionally read and write English and take note of English language postings of their industry. That's why we've invested heavily in the testing you can see.

Are you saying the quality of the edge on a modern straight razor is inferior to that found on older vintage straight razors? That this is due to different methods employed today to keep the unit cost down of the finished product?

Bob

Originally Posted by razorfranken81

Certainly we agree a line separates two points, but if the points on the line were only moving in reference to one another while upon any arc, the metal represented by the boundary aside their motion will be a curved boundary.

So it sounds like you're saying that razors were never finished on a hone when they left the factory ? If that were true & this miniscule curved boundary you refer to existed don't you realise that it would disappear with the first few strokes on even a barber's hone ? Do you think we should all send our razors back to the factory for honing to maintain that pristine grind ? Maybe people did that in Victorian times but I've honed my own razors for nearly 40 years & even took money from others to do the same at one time. Never had a complaint about comfort or edge longevity.

The sharpest razors in existence, the Japanese wakamisori are a single bevel which are all honed & maintained on flat stones.

To me this whole concept of concave edges sounds like a marketing ploy but ....

I look forward to see these certified edges if that means the razor's shave readiness will be improved over past levels & I hope the Dovo warping & frowning issues will be addressed at the same time.

yes of course BobH, there are many reasons the quality cannot precisely equal the peak of Victorian production - master grinders are always highly skilled, but the labor pool of such was massively larger then, the costs of production dramatically reduced due economies of scale (child labor was normal), and we have lost the lapidary productions of hard natural finishing wheels as well, likely a wheel has not been the final step in fifty years or more at a German factory setting. Raw materials sometimes effectively pass away, there is still abalone but there is not still abalone shell commercially available in the size required for a scale, so we can do only inlay or partial/segments. Similarly the abrasives may be underfoot but without a lapidary that possesses the tremendous skill needed to fashion a single piece of such abrasive, it is effectively equivalent to extinct.

Because of this acknowledged limitation, this forum would apparently prefer the item cease its production, so that we may all only reflect on the zenith we have not approached prior or since, and appreciate its unmatched quality and price combination. Let us finish play of basketball as well for most alive have seen the Michael Jordan era, and concede it cannot be equaled; as the statue states from the first of the three retirements "the best there ever was, the best there ever will be".

Just remember if modern production ceases, those coveted items are in finite supply, and all their labor costs were paid many generations ago...then you can maintain forum for devotion to the antiques and eschew the inferior modern pieces cutting corners to save time and money.

Originally Posted by razorfranken81

yes of course BobH, there are many reasons the quality cannot precisely equal the peak of Victorian production - master grinders are always highly skilled, but the labor pool of such was massively larger then, the costs of production dramatically reduced due economies of scale (child labor was normal), and we have lost the lapidary productions of hard natural finishing wheels as well, likely a wheel has not been the final step in fifty years or more at a German factory setting. Raw materials sometimes effectively pass away, there is still abalone but there is not still abalone shell commercially available in the size required for a scale, so we can do only inlay or partial/segments. Similarly the abrasives may be underfoot but without a lapidary that possesses the tremendous skill needed to fashion a single piece of such abrasive, it is effectively equivalent to extinct.

Because of this acknowledged limitation, this forum would apparently prefer the item cease its production, so that we may all only reflect on the zenith we have not approached prior or since, and appreciate its unmatched quality and price combination. Let us finish play of basketball as well for most alive have seen the Michael Jordan era, and concede it cannot be equaled; as the statue states from the first of the three retirements "the best there ever was, the best there ever will be".

Just remember if modern production ceases, those coveted items are in finite supply, and all their labor costs were paid many generations ago...then you can maintain forum for devotion to the antiques and eschew the inferior modern pieces cutting corners to save time and money.

Thank you for confirming that. Then there really was no need for your long winded and torturous to read post that came across as being a bit arrogant. It could have been more concise and therefore better understood negating the need to ask for clarification in the first place.

Bob

Mr. razorfranken

I suggest the following:

Find someone fluent in your language and
Can write in fluent English and
Has the ability to compose a clear, concise message.

BobH you are not compelled to read anything, and I do not know how you would feel if you were a working professional in any capacity for twenty years and were told how wrong you were on an objective data point about the actual production to which your profession is devoted by self taught experts in an internet forum who lack the formal training required for your profession like any, but hopefully this scenario will come for you one day. If technical writing from a mechanical engineering standpoint is too verbose, I am sorry, it does take much longer to write a short letter than a long one in a hurry.

Someone had asked how much is the concavity upon the cutting edge itself at the apothem of the arc cut in to the bevel form, while it varies from grinder to grinder and model to model I can state it is likely, today, less than .002mm. But that is not the complete story; you have ignored meaningful changes to the reduction of the edge radius and effective cutting angle. Instead of thinking about the small width of the bevel form as an expression of the razor whole, consider a common standard for today as expressed across a typical 5/8" Solingen full hollow ground blank. Between the spine and the terminus of the cutting edge on such a razor, the abrasive will extend .032mm closer to the center of the metal than with any flat object by today's meager standard for wheel forming [and with a 20cm wheel common in 1900 it will extend .644mm closer!] The abrasive must then return to that same furthest point from the spine upon the metal, and in so doing, it will encounter the cutting edge profile near to but spineward of the cutting edge terminus. This is not an area that is fixed in position, use your thumb nail and draw your blade edge toward the nail, what occurs? The blade will flex and return to position if properly ground and tempered. And thus what occurs is that the final portion of the cutting edge furthest from the spine is gently extruded away from the spine during the sharpening. Only by using a wheel (or arc chord shaped hone) can you design the curvature of the abrasive to take advantage of the unique flexibility (in the area where the cutting edge is <.2mm) of the steel used for razor production.

You may not be noticing the difference for forty years in these two examples, but that does not mean the factory razor did not have a length advantage. It did, and when it was corrected by your rehoning, your new cutting edge terminus must take place at the position at the prior concave edge's apothem, so immediately you have discarded useful metal. If you had done everything you have done for the forty years but only changing the whetstone geometry, you would have retained the length and added your higher refinement than financially possible in a professional setting today for an open razor to be produced en masse and sold in retail markets where retailers, shipping companies, brokerage houses, and steel forges must all receive a portion of revenue.