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Hanging Hair Test (HHT) For Knives --- Useful Metric Or Parlor Trick?

Posted by jasonstone20 
Hanging Hair Test (HHT) For Knives --- Useful Metric Or Parlor Trick?
September 15, 2019 06:28PM
[sharprazorpalace.com]
[coticule.be]

I have asked some experienced sharpeners about using the HHT for knives. Even for straight razors, the HHT is controversial. It appears to not be a useful metric for knives that are used for EDC or the kitchen. I have had mixed results, and although I can get knives to pass an HHT, it really doesn't tell me anything useful about the sharpness, other than it can pop hairs. The tree-topping arm hair seems to be a better metric from the people I have asked, and in my own experience that and popping beard hairs seems to work better. There is nothing an knife edge that passes a HHT can do that a blade that tree-tops arm hair can't do in EDC use and kitchen use. In face, chasing a HHT 3/4 can damage the edge leaving you with an unhealthy edge that won't have good edge retention. If an edge can pass a HHT and readily pop head hairs straight off the stone or a small amount of work on a strop, great, but if not I really don't think it is worth chasing. I have been doing that for a few years, and I think it is a waste of time.

Edit:
PS: Also, if you do get a knife to pass a HHT 3/4, if you let it sit overnight, not used, it often will not pass the test in the morning. Plus if the knife is under 15*DPS/30* Inclusive, it usually will pass easily, and if it is over 15*DPS it will just whittle the hair, not pop it completely in half.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser



Edited 2 time(s). Last edit at 09/17/2019 06:16PM by jasonstone20.
Re: Hanging Hair Test (HHT) For Knives --- Useful Metric Or Parlor Trick?
September 18, 2019 06:30PM
I have a strange obsession with getting knives to pass a HHT 3/4 and still slice paper towel. I am trying to use the arm hair tree-top, but I still try to get the knife to pass a HHT 3/4

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: Hanging Hair Test (HHT) For Knives --- Useful Metric Or Parlor Trick?
September 19, 2019 01:57AM
Concerning the whole HHT, I understand that it's mostly a more gimmicky thing that can vary wildly from a number of factors, but just like slicing paper it's a test with a definitive Pass/Fail result, which is enticing as far as testing goes. Plus, it's difficult to combat years of placing that test as the apex (pun intended) of all tests.
Re: Hanging Hair Test (HHT) For Knives --- Useful Metric Or Parlor Trick?
September 20, 2019 02:36PM
Luis,
Yeah, that's is one issue about the HHT, it isn't just pass or fail. The issue I am trying to solve is how to get a reliable, pass fail test for high sharpness, ie above shaving sharp. One item I tried that I think might be doable is cigarette paper. Also, I think a sharpness tester like the popular one might be an option. I built one myself, it just isn't the easiest thing to use.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser



Edited 1 time(s). Last edit at 09/20/2019 02:37PM by jasonstone20.
Re: Hanging Hair Test (HHT) For Knives --- Useful Metric Or Parlor Trick?
November 06, 2019 04:44PM
I just measured my OCB Hemp Papers vs JOB Single Wide Papers, and they are the same thickness, so if you can't find the OCB papers, the JOB should work.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
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