Thread: Burnishing

I would like to know more about burnishing, as it is applied to the straight-razor honing and stropping process. For example, in using a black hard Arkansas, I have always sensed that the stone was burnishing the blade in the end, rather than sharpening. Similarly, my sense is that when one says that one is "realigning the edge" in stropping one is, in effect, burnishing. Yet the blade is moving edge-first in the former case and spine-first in the latter.

In printmaking, the scraper on a copper plate introduces the scratches, while the burnisher presses them down to arrive at a finer finish as needed. The pressure needed to achieve a counter-effect in burnishing is greater than the pressure needed to create the initial effect in scraping. If a honing sequence can be considered as a series of finer and finer scrapings, with stropping being considered the introduction of burnishing, could not the burnishing effect be introduced earlier in the process, eliminating the need for the final stage(s) of scraping? Is this basically what pasted strops are doing, or is this more of a question of increased stropping pressure or stropping on denser surfaces rather than leather?

So, not sure what it is you are asking. Burnishing in printing, from what I have read is to make corrections in a copper plate or make a smooth surface. In honing we are trying to perfect an edge. So while there may be some similarities in the process the end goals are different.

In honing there are two goals, one is sharpening (bevel setting) getting the two planes (bevels) to meet creating a sharp edge that will cut hair.

The other is comfort. While you can get edges to meet with almost any grit and time, larger grits make the job faster. 600 -4,000 are acceptable grits with about 1k the best compromise of time and damage, (weakening the steel).

While the 1K will leave a sharp edge, it will be uncomfortable as the edge is saw tooth, a result of the deep stria, lands and grooves created by the grit of the stone.

The goal then is to reduce the land height without removing the bottom of the groove or reducing the land height by replacing the 1k stria with shallower stria. There by straightening the edge, (less saw tooth).

Finer grit hones, pastes and stropping all do similar things to the stria, the process is the best compromise of speed and comfortable resulting edge.
Stropping on leather probably comes closest to burnishing, but probably still microscopically removing metal.

I really haven't seen the term burnishing used much at all as it relates to straights or honing or stropping. We use dressing and polishing but I'm not sure it's the same thing.

It's an interesting proposal, but I think you may have answered your own question in the example you gave of the printing process. It takes more pressure to plastically flow the metal than it did in cutting the metal. So if you went to stropping or another burnishing process too early, you'd never be able to plastically flow the larger "grooves" since the pressure required would probably damage your thin blade before sufficiently burnishing the edge.
It only takes a very light touch on a high grit abrasive to smooth out the grooves. It would take much more to plastically flow the material.
Just my hypothesis

Adding on...not to mention the pressure required to "flow" tempered steel is a few orders of magnitude higher than to move copper! How much pressure are you planning on applying to the strop?

Thanks guys. In doing some research prior to starting the thread, I came across references to glass hones and honing on metal plates and the like. But these were not active threads so I chose to start a new one. My sense of "burnishing" with a hard black Arkansas is akin to this kind of honing, in that it feels like glass when smoothed and there seems to be a point, in viewing the bevel with a loupe, where scratches are sort of flattened or pressed down rather than introduced. But this is subjective on my part.

As for the print-making analogy, the points about pressure damaging the edge and copper versus steel are good ones. Perhaps I was mistaken in referring to the pressure needed to burnish out scratches left by a scraper, rather it would have been better to refer to the deeper lines of the burin that would need that pressure, with the burnishing of a fine scraping needing far, far less. Not to go overboard with the analogy, but it provides a model for me of what may be going on invisibly at the microscopic level. The burnishing effect of stropping being slight, if there at all, perhaps it is due to the suppleness and smoothness of the leather surface employed. By substituting a denser smooth substance like a sheet of glass or a polished piece of hardwood like maple, and considering this substance as a "neutral" honing medium by itself, rather than applying pastes or surfacing it to create grain, perhaps the burnishing effect might be increased while maintaining the same relative amount of contact pressure as in stropping. In any case, the surface would have to be smooth. Fire-hose linen is supple, but its rough surface allegedly abrades the edge minutely, whereupon the leather smooths this line back out.

In some ways I have kind of wondered about the process myself.

I wondered why there are so many old blades, pre 1900 still out there that obviously were well used, but with so little spine wear. Clearly they were not taping spines.

I believe we have become obsessed with honing, recently and old time maintenance was more about polishing with high grit stones, pastes and stropping as part of a regular maintenance program. Almost burnishing and as Royalcake says with a “very light touch”. Most probably bevels were not reset except to correct damage.

We now, in a press for time choose to reset a bevel than spend the time to gently bring an edge back to life or to maintain it.

Time and the ability to re-establish a shaving edge quickly is the reason we first turn to re-setting the bevel.

Before time was not an issue and many thing were done by hand with skill and took… as long as they took.

Originally Posted by Euclid440

Before time was not an issue and many thing were done by hand with skill and took… as long as they took.

When an activity is done for monetary gain, time is/was always been an issue. Things took as long as they took but you also got charged for it. That is why things become cheaper with automation...less man hours and skill involved. I think people were much quicker to pull a mediocre regrind or cheesy attempt to fix it themselves before turning to professional (highly skilled help) or just replaced the razor. Look at the razors with for sale with bound in string scales as a "repair."

Originally Posted by Euclid440

In some ways I have kind of wondered about the process myself.

I wondered why there are so many old blades, pre 1900 still out there that obviously were well used, but with so little spine wear. Clearly they were not taping spines.

I believe we have become obsessed with honing, recently and old time maintenance was more about polishing with high grit stones, pastes and stropping as part of a regular maintenance program. Almost burnishing and as Royalcake says with a “very light touch”. Most probably bevels were not reset except to correct damage.

We now, in a press for time choose to reset a bevel than spend the time to gently bring an edge back to life or to maintain it.

Time and the ability to re-establish a shaving edge quickly is the reason we first turn to re-setting the bevel.

Before time was not an issue and many thing were done by hand with skill and took… as long as they took.

I agree with this in regard to our having become obsessed with honing, although the polishing with high-grit stones, depending on what is considered high-grit, may also be a current obsession. A very light touch may apply to abrasion, but I have my doubts with regard to burnishing. What does "almost burnishing" mean, other than very light abrading? And what is a high-grit stone in the old-time sense, if that is what is to be preferred to today's obsessions? If it is mid-range by today's standards, can't a light touch be applied here? And if that is not enough, what is to follow it apart from higher-grit stones in the modern sense?

Originally Posted by Euclid440

In some ways I have kind of wondered about the process myself.

I wondered why there are so many old blades, pre 1900 still out there that obviously were well used, but with so little spine wear. Clearly they were not taping spines.

I believe we have become obsessed with honing, recently and old time maintenance was more about polishing with high grit stones, pastes and stropping as part of a regular maintenance program. Almost burnishing and as Royalcake says with a “very light touch”. Most probably bevels were not reset except to correct damage.

We now, in a press for time choose to reset a bevel than spend the time to gently bring an edge back to life or to maintain it.

Time and the ability to re-establish a shaving edge quickly is the reason we first turn to re-setting the bevel.

Before time was not an issue and many thing were done by hand with skill and took… as long as they took.

I think this is a false assumption. If it is an old blade that shows little spine wear, How do you know that it was well used, as opposed to hardly used at all?

I have an old blade from my grandfather. It started life as a medium hollow (etched into the blade). He did not tape the spine and it is now a near wedge. He loved it almost to death.