Thread: Thoughts on HHT...

Yep, so many variables with HHT it is useless unless you calibrate to yourself. Over the years, my HHT has become the very fine hairs on my outer fore-arm. When I can tree-top those with ease all along the edge, I've usually got a velvety-smooth shaving edge. YMMV is very much in play on these final pre-shave honing tests.

Originally Posted by Gasman

Guess that would give someone an idea. But ive seen close-up pick of DE blade edges that look scarry toothy. As I said. It was only a thought.
BTW, I bought some hair extensions for my testing. Works so much better than the stuff I got from my granddaughter.

Jerry

For most men, the beard hairs are a lot more coarse than head hairs. As we age, our beards often become even more coarse. Thus, the hair from your granddaughter is likely to be too fine to be an accurate predictor of shave ready for your beard. Perhaps, the hair extension you purchased is coarser so it works better.

I do not do the HHT, but do an AHT. My arm hairs seem to be thicker than my head hair. However, even at that I need to get an edge sharp enough to pop arm hair about 1/2" above skin level in order to get a great shave. That is why everyone needs to calibrate their test method for their own beard.

Just some thoughts to add...

You need to always use the same hair - hair extensions are a good source of hair. It needs to be good quality and clean.

Root-in tests differently than root-out.

You can’t compare the sharpness of edges generated by different methods very well. That means you can’t tell if a jnat edge is sharper than a thuri edge is sharper than a coti edge is sharper than a DE edge (most of which are coated these days).

You can usually tell if the edge is improving with the same general kind of progression, say synthetic even of different brands.

I like to use HHT as a final bevel set test at 4-5k. I do a half strop, 10 canvas/20 leather and the hair should cut cleanly and easily all along the edge. You can test every mm.

Practice helps, just like any other test.

When I use an Arm Hair test to check an edge across the blade, it is a compass, a quick test to tell if I am headed in the right direction.

I also use, TPT, (Thumb Pad Test) and most telling for me, a visual test, a look at the stria on the bevel, does it match the grit, and that stria reach the edge fully, especially at the heel and toe. And then look straight down on the edge, for shiny reflections.

All tests are quick, and easy to perform, if an edge is passing all 3 tests, chances are it will shave just fine.

None of the test individually are conclusive, only the shave test is conclusive. It will shave well or very well. Occasionally I will go back to the strop or hones if I feel I can squeak a bit more from an edge.

I equate all test to a Dyno. All race cars go on the Dyno to fine tune the best performance from the motor. But the best performing motor does not always win the race. If the Dyno was definitive, there would be no need for the Race, the Dyno would be the arbiter.

The goal is the race, the Dyno is just a test. For us the goal is the shave, sharpness counts but absolute, maximum hair popping sharpness is not the goal. One can easily make an edge so sharp it will exfoliate a layer of skin and is uncomfortable.

But to answer your question, “Is it possible to have such a fine straight edge that its no longer toothy enough to pass an HHT?”

No, all grit will leave stria, it must, or it will not cut, and all stria will leave a “serrated” edge. A true HHT should be a push cut, not a slice. A very sharp blade should pop a hair, much like a knife pops a watermelon.

Sharp is easy, sharp and comfortable is difficult. It is said the difference between a good and great edge is about 2% more. In the abys is the 2% and each of us must find it, because we are all using different stones, razors, strops and technique. What works for me, may not reach the 2% for you.

Originally Posted by Gasman

Is it possible to have such a fine straight edge that its no longer toothy enough to pass an HHT? Or would it be that if an edge being that level of fine it would still find the sections between the hair and still pop it off?

Most dedicated finishers aim to create the smoothest possible, toothless edge. And stropping on clean leather delivers a manifest improvement of the edge's ability to sever a hair.

How finer the saw-tooth pattern, how keener the edge needs to be for the same cutting performance.

I believe the smoothest most toothless edge that's still keen and shaves well will pass the HHT, if it's "so fine" it won't pass a HHT I think the edge is ruined and has lost its keenness and won't deliver a good shave, nor a good HHT result.


So far I haven't found a finisher that delivers an edge that's too fine.

HHT was a bit of a fad in days past, but most found it is so fickle that it does not consistently reflect shaving ability.

Most of us, me included use it as a test (tree topping arm hair) during honing to insure we are continuing in the right direction across the whole edge, (does the toe or heel, need a bit more work?) and not a definitive edge test.

Your question about tooth, is probably valid. As butchers know well you can tailor an edge to the task and for cutting meat or skinning a toothy edge can be beneficial as opposed to a razor edge or folks would be skinning with straight razors. Scalpels are not that sharp, for cutting skin and tissue, skin is surprisingly tough.

One could easily test this theory, by creating a mirror bevel, laser straight edge with high grit .3um film, (about 60k grit) and sub-micron CBN or Diamond paste, up to .10 (200,000 grit) easily obtainable or finer to .005um 3.2 million grit, not so easily obtainable. Any thing over about 20k is near or mirror polish and very straight edge. An edge begins to get very straight at about 8k.

They will still cut my arm hair for me. But I will be damned if, I can tell the difference between a .10um CBN edge and a fine Jnat or Ark edge for cutting arm hair. Shaving is another matter, readily determined by smoothness of the skin, weepers and/or discomfort, for me. .25um is about the most my skin can handle.

What does matter is stropping. Try this yourself. You try an HHT and it does not pass, strop on linen and leather and it passes. Stropping on leather straightens the fin, the very thin edge, probably not removing much metal, stropping on linen depending on the linen can remove metal, microscopically and straighten the fin, but not like flatter, smoother leather.

Add to that different leather can vary in abrasive quality, depending on the leather, how tanned and cared for. There is a leather strop progression, but for the average guy whacking whiskers, is TMI.

What highly polished super straight edge produce are also super thin edges, that while they shave well for a while, shaving and stropping will cause the fin, the very edge to flex and break off causing Micro Chipping down the road.

Even a “mirror polished bevel has stria, and micro serrated edge, we just cannot see it at 400X. You can on an SEM.

Your mileage may vary…wildly but can be some fun for us edge obsessed.

To kind of put into perspective, I saw a video of a guy slicing a tomato with a Wooden knife. What does that say about those that swear about Tomato cut test, what would that shave like?

To me it says, he can cut tomatoes with his wooden knife. Yes, the tomato test can work for edge testing, but really it just means you can cut a tomato and or are headed in the right direction with sharpness.

What your question says, is you have stopped circling and are descending into the abyss…

Wooden knife video

Like @gssixgun advised use a DE blade to gage your HHT but I use an old badger shave brush for the hair instead of what’s in the hairbrush

descending into the abyss…

Yep, thats me. I got to quit thinking about these thing so deeply.
Its just sharpening, right?

Originally Posted by Jnatcat

Like @gssixgun advised use a DE blade to gage your HHT but I use an old badger shave brush for the hair instead of what’s in the hairbrush

Check your edge under a microscope after using anything coarser than human hair. You may get a shock.

"What your question says, is you have stopped circling and are descending into the abyss…"I feel so empty now.

Reminds me of the Neitzche quote: "If you stare long enough into the abyss, the abyss stares back into you."
-"I just wanted to hone razors, Dr.-really!"
-"Now try to stay calm, Mr. SRP man. You know we don't allow sharp objects in here. Maybe you can make something with the popsicle sticks during craft time."