Effect of blade geometry on shave, hht performance

I have two new razors I just honed. One is a hollow ground torrey, which touches a hanging hair and the half not being held jumps up and seems propelled away from the other half. Its quite remarkable actually. Without any pressure, it touches a hair and there is a light popping sound.
My other, a near-wedge F Herder behaves quite differently. It will catch a hanging hair and, more often than not, slice it up the middle, often without fully severing it. It gives hanging hairs a shave. I am wondering if:
A. Others have noticed this or if the wedge just isnt as sharp as the hollow-ground blade (certainly every time I do a few [~50] laps on my .25μ pasted strop it still seems to benefit marginally).
B. If these are common traits of the grinds and how the hht responds to them, should they give similar shaves, notwithstanding the different hht results?

Let's see if I can help steer you correctly...

For the HHT to mean anything at all, first you must quantify it, which means that after you get a few razors to shave decently from your honing efforts, then and only then should you try the HHT on a razor that you know shaves your face well...

Basically the shave test is what counts, then if you want to play around with the HHT you can figure out how the hair that you are using relates, if at all to a shave ready edge that you produced ...

Now to give you the bad news :( a shave ready edge, is a shave ready edge, and should react the same to a hair, whether it is on the face or in the air.. So given the same source of hair and the same motion etc: when using the HHT then yes, your wedge is not as sharp as yer hollow... BUT the HHT isn't that accurate :rofl2: until you quantify it... back to square one

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Originally Posted by Rsq

A. Others have noticed this

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No, there simply is no such relationship between the razor grind and the HHT performance.
As Glen, suggested, start with the test that matters. You also need more than a single data point before considering generalizations.

LOL, I just love these HHT threads. Good advice given above. I would forget the HHT as a test for shave ready and just enjoy the results for now. A good test for shave ready is to shave arm hairs prior to a face shave. If you talk to any Barber with experience he will tell you that facial hair is much different than the hair on your head and the majority of the rest of your body. We won't go there. The best advice we can give ya is to take your newly honed razors to your next shave along with one of your current shavers. Shave a small section of your face with the newly honed razor WTG. If that works well continue shaving with it. If not back to the hones. Many of the guys that professionally hone razors will shave a small section of their face as a final test to see if the razor is shave ready. Do note that there are many levels of shave ready edges which vary even from the same person doing the honing. The HHT is a fun test but it usually is not very reliable. I have seen many a razors not pass the test but still shave well.

I have to agree that the HHT test is over-rated. If a razor doesn't perform a HHT test, it doesn't mean that it won't shave well.

Without stirring the coals, the HHT test is sort of a parlor trick. The test is demonstrating the ability to separate hair sections, not actually cut it. I can't claim any proof, but when testing two razor of equal (geometric) sharpness, a smooth, clean edge does worse than a sharp, saw-like edge with this test.

Of course, this is my opinion.

just because the razor can pass the HHT , does not mean it will feel great when you shave with it.
HHT gives indication of sharpness but not of smoothness.
Just shave with the razors and forget about the HHT.

I've probably said this before in other HHT threads, but I have only been able to get one razor to pass a HHT.This razor also happened to give me the worst shave I've ever had. Felt like shaving with a garden rake'

This is interesting. Ive honed 5 razors, and found that the hht has been a reliable indicator until i did it with a vintage dubl duck. This passed the hht just fine, mybe not as vigorously as my dovos, but it then did a number on my face. Three days later, I still dare not shave for all of the razor bumps it left. Worst shave since the first time i used a straight, and maybe worse than that. Nonetheless, I will not put a razor to my face until I can get it to pass the hht. If nothing else, it does indicate a certain minimum degree of sharpness.

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Originally Posted by Rsq

This is interesting. Ive honed 5 razors, and found that the hht has been a reliable indicator until i did it with a vintage dubl duck. This passed the hht just fine, mybe not as vigorously as my dovos, but it then did a number on my face. Three days later, I still dare not shave for all of the razor bumps it left. Worst shave since the first time i used a straight, and maybe worse than that. Nonetheless, I will not put a razor to my face until I can get it to pass the hht. If nothing else, it does indicate a certain minimum degree of sharpness.

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Sounds like you are at a loss for a better test so you are relying on a test that has been proven to be of no value to you. Try shaving arm hairs. While not as good as a shave test it would give better results than the HHT which has failed for you. It's your face, just trying to save you and others reading this thread some grief. Good luck.

Joed, my dear friend, how right you are.

I have learned what little I know of honing from three masters: Lynn, Randy, and Sham. These gentlemen are the gods of honing. Yet none ever framed the blasted hanging-hair-test as the ultimate for the blade's shave-readiness. To these craftsmen it's the shave test that determines if the razor is shave-ready. So I continue to listen to them as I refine my humble honing skills in their image.

Stay well.

The problem is that i can shave my arm long before I can pass the hht. And with things I would never put near my face, like my pocket knife and kitchen knives. That seems even less reliable

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Originally Posted by Rsq

The problem is that i can shave my arm long before I can pass the hht. And with things I would never put near my face, like my pocket knife and kitchen knives. That seems even less reliable

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All my pocket knives, and wifes kitchen cutlery will shave hair off legs, arms, you name it. None of them pass the hht, and none are good enough for a face shave either. I am damn new to this straight razor stuff, but I dont see how the arm hair thing is any indication when most common knives after a med ark will take hair off an arm like nobodys business.

If tests like HHT and TPT don't give you enough information about your edge, and you want something other than just shaving with the razor, you should try a magnification. Unfortunately how high of a quality you need is something you'll have to figure out yourself. I know that I can put a good edge on a razor without ever mechanically testing the edge, only observing it in a microscope with good optics, and that the $50 USB microscopes are not adequate for that task. On most razors I can also do it by just observing the water bead in front of the edge during honing, but for consistency I need the high quality optics as well.

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Originally Posted by Rsq

The problem is that i can shave my arm long before I can pass the hht. And with things I would never put near my face, like my pocket knife and kitchen knives. That seems even less reliable

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A razor off the bevel setting stage on a 1k (norton if you like) will shave arm hair. that doesn't mean it will shave your face, a better gateway test is to see if it pops arm hair against the grain with the razor off your skin maybe 5-6mm.

basically there's 2 arm hair tests.

The TPT is your biggest friend in conjuntion with this. and a loupe helps a lot too.

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Originally Posted by Rsq

The problem is that i can shave my arm long before I can pass the hht. And with things I would never put near my face, like my pocket knife and kitchen knives. That seems even less reliable

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Originally Posted by ubet

All my pocket knives, and wifes kitchen cutlery will shave hair off legs, arms, you name it. None of them pass the hht, and none are good enough for a face shave either. I am damn new to this straight razor stuff, but I dont see how the arm hair thing is any indication when most common knives after a med ark will take hair off an arm like nobodys business.

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Thats because the AHT is for a set bevel, nothing more... once the bevel is true and fully set (not overhoned) then all you are doing to refining the edges as you go.....It really is just that simple...

I think people are overlooking the most important statement made in Glen's first post: calibration.

All test are rubbish. All. They are not shaves. They are simulations, or models, of a shave, at best. And they are poor ones at that. They are a quick and dirty way to ascertain whether you should bother moving onto the next step, whether that be moving to a higher grit hone, or moving to an actual shave.

Their only worthwhile use is in conjunction with rigorous evaluation and calibration to your shaves. You must figure out, for yourself, how a certain test correlates to the shave you should expect. No two people's tests will be the same in this regard. No two razor's tests will be the same in this regard. You need a lot of data to calibrate these tests so that they become useful for you.

In any event, that is how I treat them. I'm not saying the OP's HHT is wrong for him, I'm just saying that as a general thing asking others to interpret your individual test results is like asking someone to comment on how badly your leg hurt when you corked your thigh. They can tell you how much a corked thigh hurt them, but only you can say how much it hurt you.

(Yes, I corked my thigh recently... :( )

James.

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Originally Posted by gssixgun

Thats because the AHT is for a set bevel, nothing more... once the bevel is true and fully set (not overhoned) then all you are doing to refining the edges as you go.....It really is just that simple...

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Glen, I can see how you would feel that way but there is more to it than you think.

Thanks Jimbo for adding the calibration comments. That is an important part that was missed. It takes a lot of observations with any test to get usable information from the results and in the end, the shave is where the rubber meets the road.

RSQ, perform both the HHT and shaving arm hairs. When doing the arm hairs go slow, don't just plow them down. Observe how the hairs are cutting. Do one hair at a time at first. The way the hairs cut will give you some degree of smoothness in the shave. Hone until you get past the popping hairs. The arm hair test will give you a test over more of the blade than the HHT will give and if you are cutting arm hairs you just need to refine the edge to give a smooth shave and the HHT can not give you that measurement. The skin on your arm is not as sensitive as the skin on your face so I need to focus to feel a slight tugging which would feel like more on my face. I guess I really don't know what you are trying to achieve.

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Originally Posted by Joed

Glen, I can see how you would feel that way but there is more to it than you think.

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Actually Joe I was trying to keep it simple and not complicate it :) sorta like the HHT should have been kept simple and uncomplicated...
When you start trying to get into degrees of sharpness tests, I honestly believe that each person really needs to figure that out on their own with their hair ... The revelation will come with experience instead of us trying to quantify our observations over this media...

what is a corked thigh?

I have coarse, curly hair, so i really need the razor as sharp as possible or I get razor bumps. Thats why i started using a straight in the first place. I like the arm hair popping test and the idea of examining the way the razor cuts one hair at a time

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Originally Posted by hoglahoo

what is a corked thigh?

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A dead-leg? A Charlie Horse? Blunt force trauma to the thigh-al area causing internal hemorrhaging into the quadricep muscle resulting in localised pain and eventual bruising?

Kinda like when my uncle caulked his thigh, but he lost his leg in the War so when he said he caulked his thigh it usually involved wood putty of some description!

James.

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Originally Posted by Rsq

I have coarse, curly hair, so i really need the razor as sharp as possible or I get razor bumps. Thats why i started using a straight in the first place. I like the arm hair popping test and the idea of examining the way the razor cuts one hair at a time

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There's nothing wrong with the HHT or the arm hair test, but you have to make sure you calibrate them continually to your shaves to get the most out of them. It really is a continual process actually, because your techniques will improve, you might get new razors, you might buy new stones or strops etc. I'm always comparing my arm hair tests to the shaves I get. There's this little patch of finer/sparser hair I have up near the elbow, and if it cuts in a certain way I'm almost sure to get a nice shave. Alternatively, if that area is out of hair, I know that at a certain height and at a certain speed, the arm hair on my forearm can be an indicator of a nice shave to come. The only way to develop these little localised tests is to iteratively recalibrate over a reasonable time period.

It is one of the reasons more seasoned straight razor shavers have less issues with things like burn or cuts - the experience time and practice have given them in assessing an edge using various tests.

James.