Thread: Does the razor 'fin' really exist?

I've been shaving with a straight razor for about two months now, and I think I may be getting the hang of the honing process, although I'm not entirely sure.

I have two questions, each with multiple parts.

1. Of the tests for sharpness I've read about on the net, including the hanging hair test (HHT), and the moistened thumbNAIL test, and the moistened thumb test, I seem to be able to most easily discern differences with the thumbnail test. I can't seem to feel anything different at all with the moistened thumb test, and can't really get the HHT to work well. Attempting the HHT, I can get the occasional hair to stick and pop, but it is not effortless for the razor to cut it. My question here is the following: are there any other tests? and my razors are able to shave me, but I have to go over the area at least twice, sometimes three and four times. Does this mean the razor is not sharp enough? I assume it should get every hair with one swipe. This brings me to my next part. I have gone through Brian Donofrio's great videos on how to prepare the Norton 4k/8k stones and have followed his advice to the letter. The stones are very flat, and lapped well with the appropriate grit sandpaper. However, I seem to have trouble getting the entire lenght of the blade to the same degree of sharpness. I gather this from the moistened thumbnail test, and also from shaving with the blades. How can I get the whole length better honed, without putting pressure on at least some part of the blade that appers to be not sharpening well?

2. I've been reading all the lore on the net regarding honing and sharpening for several weeks now and there appear to be widely divergent views on how to properly sharpen blades, how to maintain their sharpness, and how to avoid breaking the 'fin'. I've also read the article on sharpening by provessor Verhoeven that is listed in the forums here and taken a good look at his SEM micrographs of the blades up close. In particular, his figure 9 shows an exceptional picture of a straight razor edge which has been prepared by a decades long straight razor shaver. On the length scale shown in the SEM image, on the micron scale, there is no evidence whatsoever for a 'microserrated' 'fin' of any kind. I'm beginning to question whether the lore is actually correct. Given the widely divergent views on sharpending, I also wonder if there are different edge morphologies that will yield a razor able to give a great shave. Has anybody here ever seen or know of good SEM micrographs of the so-called 'fin' showing microserrations? There are web sites that claim it is visible when viewed under an optical microscope. However, given Verhoeven's SEM micrographs not showing a 'fin', and due to the low depth of field of optical microscopes where it is possible to see artifacts due to abberation at high magnification that will make the razor edge appear to have microserrations, I'm beginning to doubt the existence of a 'fin'. Does anyone have any concrete physical evidence for the 'fin'? I ask because several sites suggest never stropping after a shave and/or waiting 18-24 hours after the shave to let the so-called 'fin' straighten out, etc...

Much thanks for any info.

Cheers,
Eric

Well to answer some of your points; if the blade is unequally sharp your probably not applying equal pressure to the hone (actually you shouldn't add any pressure to it only the weight of the blade with exceptions from blade to blade) or doing something as you either turn the blade or remove it from the hone. This is not uncommon and it takes experience to consistantly hone and have the blade equal throughout. Watch your blade and ensure it remains in contact with the hone at the proper angle and your not lifting it off the hone at some point. This is probably the number one problem newbees have. keep at it and it will improve. As far as the tests go remember these are just indicators to help you in the process. Shaving is the acid test. You can pass all the tests with flying colors and still not get a great shave so I wouldn't worry too much about the tests. Start with the pyramid scheme and try some arm hair shaving (above the skin) and see how that works for you.

As far as the fins go I think people obsess about this thing too much. A blade should have striations or scratches on it which shows the honing pattern. The higher the grit the finer the scratches. I don't worry much about micro striations or teeth I just hone until its sharp and then shave with it. If it needs more I do more. I have a very fine microscope and yes its interesting to look at the blade but it really don't mean didley. I've seen beautiful edges under the scope that didn't shave worth a damn and edges that looked awful that gave a fantastic shave. I'm sure some of the others here will give a long discourse on this subject but hey its theory and nothing more. At this point in your learning curve you should be concerned with the practical aspects of this thing. Thats my take on it for what its worth.

The bottom line is like the guy who asked for directions on how to get to carnegie hall and the guy said practice man, practice.

Thanks for the quick response. I have one more important question. I have two razors, one Dovo 7/8 1/2 hollow, and a Thiers-Issard 6/8, full hollow. It's the Thiers-Issard I just can't seem to get sharpened properly. I've been reluctant to take too many swipes on the 4k stone for fear of overhoning it on a lower grit number stone. But I've taken lots and lots of swipes on the 8k. I'm hoping I'm not destroying the blade. Is there any chance of ruining the blade just by overhoning on the 8k stone?

Eric

Originally Posted by ericm

... the moistened thumbNAIL test, and the moistened thumb test, ...

The thumb test is done dry.

Originally Posted by ericm

How can I get the whole length better honed, without putting pressure on at least some part of the blade that appers to be not sharpening well?

When you put pressure on the blade you disable it from creating the shaving edge not enable it, and the best way to get consistently sharp edges is to use the x pattern while honing.

Originally Posted by ericm

I'm beginning to doubt the existence of a 'fin'. Does anyone have any concrete physical evidence for the 'fin'? I ask because several sites suggest never stropping after a shave and/or waiting 18-24 hours after the shave to let the so-called 'fin' straighten out, etc...

I've read that too, but The Grand Experiment is so far disproving that bit of 'wisdom'. The fins are there. Do the thumb test dry and you should feel them.

I am more and more of the mind that the 4000 side is great in helping establish a great edge. Don't be afraid of it with the TI. Those guys are very resilient. It probably needs a few good laps. Try a small pyramid; 1/5, 1/5 3/5, 1/5, 1/5, 1/3, 1/3, 1,3. A very little firmness in pressure on the hone should only be considered for certain blades (like the resilient TI) and at the beginning of the pyramid. That's MHO BTW, eh!

X

A full hollow razor needs absolutely no pressure to hone; very hard to do in concert with honing a 1/2 hollow which is a completely different ballgame.

You can sharpen a razor with striations or you can sharpen it on higher and higher grits, and higher pastes out to .25 and both will shave well. I find a razor with striations shaves much better, and is easier to achieve with less equipment.

The magical fin is something I'm not really ready to buy into yet.

If I push a car downhill with the clutch in I could convince you that that is the way a car drives, but eventually you'll learn, only by practicing, that you do in fact need the gas pedal. Shaving is the same way, if I show you a pic of a razor ultra sharp and tell you thats correct what else are you to believe? You don't even see them shave with it. I prefer to use the advice in the barbers manual and create striations. Shaves better, easier to achieve, and I don't need to use pastes at all. And in case 20 of my friends stop by I can shave them all, just like a barber, instead of using a gentle fragile edge I create, and then recreate, and then recreate. Both methods work though. Really well in fact for most.

You won't see me waiting a day between shaves with the same razor.

The fin on the other hand would probably show itself better if you shaved once a week with a 7 day set. You'd probably let the razor grow back (if that happens) and knock the rust off stropping. The "fin" and striations are different. I've seen the importance of striations. I've never seen any evidence of a 'fin'. That doesn't mean it doesn't exist but I think you would have to NOT strop after shaving, not even dry the blade and let it sit overnight and try and shave the next day to discover that its not working as well, then you'd wait a few days and knock off the dried out rust between the microserrations and blam, it works and you believe in a 'fin"...still exists, you just don't see it often enough, mostly because of the way we treat our blades and also because of modern steel treatments (modern being 1900 and newer).

I've never bought into the basic concept that a fin grows either. But that doesn't mean it doesn't happen, I just can't say I've ever seen any evidence of it.

Striations on the other hand are very useful, and obtaining them with the 4K is one method (not the best in my opinion, its a really low grit). But try a pyramid method instead, it shave great and is easy to obtain. You can maintain it a long time with just one stone. You''ll need to retouch on 4k about once a month.

Originally Posted by ericm

However, given Verhoeven's SEM micrographs not showing a 'fin', and due to the low depth of field of optical microscopes where it is possible to see artifacts due to abberation at high magnification that will make the razor edge appear to have microserrations, I'm beginning to doubt the existence of a 'fin'. Does anyone have any concrete physical evidence for the 'fin'? I ask because several sites suggest never stropping after a shave and/or waiting 18-24 hours after the shave to let the so-called 'fin' straighten out, etc...

Much thanks for any info.

Cheers,
Eric

I was waiting for someone to notice this, that is why I posted those links... I for one, am not seeing any fins on those pics, and I think the trick is to bring the two sides of the edge to a smallest surface possible. On machine ground razor blades and on expertly honed blades this surface is aprox. .35 - .4 microns. that's it, no fin, no serrations, just polished sharp edge...

Nenad

The thumb test produces a tickling sensation. Those, I assume, are the fins.
Shakespeare said the razor's edge was 'invisible'. We can still feel it though.

X

The ticling sensations are your fingerprints ridges going over the edge. Sheaksp..whatever was right. who cares, as long it is sharp...

Originally Posted by ericm

Thanks for the quick response. I have one more important question. I have two razors, one Dovo 7/8 1/2 hollow, and a Thiers-Issard 6/8, full hollow. It's the Thiers-Issard I just can't seem to get sharpened properly. I've been reluctant to take too many swipes on the 4k stone for fear of overhoning it on a lower grit number stone. But I've taken lots and lots of swipes on the 8k. I'm hoping I'm not destroying the blade. Is there any chance of ruining the blade just by overhoning on the 8k stone?

Eric

You certainly can destroy an edge by overhoning on any stone. The coarser the stone the easier it is to overdo.

When you say alot of swipes how many is alot? I would go very easy on the 4K. It shouldn't take much with that stone unless the edge is in very bad shape. With the lead hardening on the TI it might require a tad of pressure but unless your well experienced in honing if your having real problems I would send it to one of the Honemeisters here rather than experiment yourself and ruin it. Once you start with the pressure on the blade you can overdo it much too easily.

I initially took about 5 sets of 20 swipes on the 8k (yesterday). Since that didn't do it, and because there was a suggestion to go back to the 4k, I did 5-10 swipes on the 4k, followed by 10-15 swipes on the 8k. I had to do that about 3 times, and then the razor started to shave. I don't think it's optimal yet, though. That took me about an hour tonight. How long does it take the normal skilled person to sharpen a blade?