| Welcome, Guest |
You have to register before you can post on our site.
|
| Latest Threads |
Protocol for BESS measure...
Forum: Edge Sharpness Testing
Last Post: grepper
05-02-2026, 08:31 AM
» Replies: 8
» Views: 7,172
|
How to prevent the edge o...
Forum: All About Edges
Last Post: WI_Hedgehog
04-30-2026, 01:12 PM
» Replies: 6
» Views: 16,214
|
Blade Taper Angle? - Supe...
Forum: All About Edges
Last Post: WI_Hedgehog
04-30-2026, 01:01 PM
» Replies: 9
» Views: 26,282
|
Knife dulls overnight aft...
Forum: All About Edges
Last Post: WI_Hedgehog
04-30-2026, 09:01 AM
» Replies: 27
» Views: 85,869
|
The DILAGON: a DIY laser ...
Forum: All About Edges
Last Post: WI_Hedgehog
04-30-2026, 07:57 AM
» Replies: 27
» Views: 110,156
|
Used Rapid Edge Extend-A-...
Forum: Relevant General Discussion
Last Post: WI_Hedgehog
04-30-2026, 06:49 AM
» Replies: 3
» Views: 7,087
|
Saved old tool (Fun with ...
Forum: Relevant General Discussion
Last Post: WI_Hedgehog
04-30-2026, 06:43 AM
» Replies: 1
» Views: 2,873
|
Mike Brubacher has passed
Forum: Relevant General Discussion
Last Post: WI_Hedgehog
04-30-2026, 06:15 AM
» Replies: 2
» Views: 2,223
|
The definition of 'blunt'
Forum: Edge Sharpness Testing
Last Post: subwoofer
02-04-2024, 12:16 PM
» Replies: 2
» Views: 4,568
|
Avg BESS score for cheap ...
Forum: Edge Sharpness Testing
Last Post: grepper
04-24-2023, 12:04 AM
» Replies: 1
» Views: 5,150
|
|
|
| How Razor Blades Dull |
|
Posted by: Rick Kr - 08-17-2020, 10:55 AM - Forum: Relevant General Discussion
- Replies (4)
|
 |
An interesting line of discussion came up recently in a maillist on the making of bamboo fly rods, in regard to dulling of edges. This may be old news to knife sharpeners, but as it pertains to razors, something we use as references or standards, I found it interesting and confirming.
Relevant discussion from the original thread is further below, immediately below are links to the source information referenced in the discussion.
Rick
Article URL
https://www.sciencemag.org/news/2020/08/...id=3445815
Video URL
https://www.youtube.com/watch?v=6kgw6j9n...tion=share
On 8/17/2020 5:32 AM, H...V... via Rodmakers wrote:
>
>
> On 17 Aug 2020, at 14:27, T...S... via Rodmakers <rodmakers@lists.canerodmakers.com> wrote:
>
>> What they don’t talk about, and the razor companies don’t tell you is that what causes most early failure in a blade is actually corrosion. Stainless is not naturally corrosion resistant, what makes it so is a microscopically thin layer of oxide that forms on it’s surface. When you shave, that oxide wears away allowing corrosion to start. As long as the metal is exposed to oxygen in the air, the oxide layer will restore itself fairly quickly, and the steel is again protected.
>
>
> I assume that is a chromium oxide? As far as I know it is primarily the chromium content that makes stainless steel ’stainless’ - and iron oxides are, for the most part, and that includes all non-esoteric oxides, non-passivating, i.e. an iron oxide layer (aka rust) does not prevent further oxidation underneath - unlike e.g. an aluminium oxide skin on aluminium.
On 8/17/2020 5:07 AM, H...V... via Rodmakers wrote:
> Note that there is nothing special about the ‘process’ they describe - see also their introduction:
>
>> Steels for sharp edges or tools typically have martensitic microstructures, high carbide contents, and various coatings to exhibit high hardness and wear resistance. Yet they become practically unusable upon cutting much softer materials such as human hair, cheese, or potatoes. Despite this being an everyday observation, the underlying physical micromechanisms are poorly understood because of the structural complexity of the interacting materials and the complex boundary conditions of their co-deformation. To unravel this complexity, we carried out interrupted tests and in situ electron microscopy cutting experiments with two micromechanical testing setups. We investigated the findings analytically and numerically, revealing that the spatial variation of lath martensite structure plays the key role leading to a mixed-mode II-III cracking phenomenon before appreciable wear.
>
> It’s only their detailed look at what’s happening at the ‘between nano and micro’ scale, after each individual use that is (somewhat) new.
>
> So yes, this is definitely also what’s happening to our plane blades on bamboo, and to plane blades on ’normal’ wood, and to kitchen knives while cutting onions on a chopping board.
>
> Way I understand it is the extent of this process is primarily dependent on the alloy type and heat treatment of the steel. My guess is that razor blade steel is harder, more crystalline, than our plane blade iron.
>
>>
>>> On 17 Aug 2020, at 13:56, T...S... via Rodmakers <rodmakers@lists.canerodmakers.com> wrote:
>>>
>>> Dear All,
>>> here is an interesting study and especially a nice video how razer blades become dull.
>>> Perhaps same is happening to our plane blades due to the hard cane fibres.
>>> https://www.sciencemag.org/news/2020/08/...id=3445815
>>>
>>> br
>>> Tapani
>>>
>>> Rodmakers List - https://rodmakers.canerodmakers.com
|
|
|
| A Sad Day For The Exchange |
|
Posted by: Mike Brubacher - 07-22-2020, 04:28 PM - Forum: BESS
- Replies (2)
|
 |
Jan Svancara has passed away and it's a sad day for all of us. Jan was a founding member of the Bess Exchange and his knowledge and willingness to share with others will be missed sorely. Jan's contributions here were too numerous to count but included his work on the Rockwell Hardness Calculator which will continue to bear his name on these pages. Jan was always thoughtful in his writings and a gentleman in every instance. Our thoughts are with his family in the Czech Republic. We miss you already Jan.
|
|
|
| Old knife restoration |
|
Posted by: grepper - 05-20-2020, 08:26 PM - Forum: Relevant General Discussion
- Replies (2)
|
 |
I enjoy rescuing old tools and giving them a new lease on life. It's always a shame when an old tool, frozen with rust is forsaken when with just a bit of work can be born again and restored to another entire lifetime of usefulness. Here's a couple of examples on page 1 and 2 of this post:
http://bessex.com/forum/showthread.php?t...576#pid576
I've done a bunch of them and have enjoyed much success, however nothing compared to what this guy does.
He uses a lot of time consuming hand work, but moreover, some very imaginative and inventive restoration ideas. Anyway, I enjoyed this video where tackles a beyond all hope, mostly disintegrated old knife. Maybe you will enjoy it too:
https://www.youtube.com/watch?v=hKV1xr2ZqJs
Here are some other hopeless, basket (trash can) cases he rejuvenated. Pretty cool. Scroll through the list of videos. There are some beautiful old tools in very deteriorated condition given a new, useful lease on life. A great demonstration of how those old, built like a tank tools can last many lifetimes... As long as someone cares to keep them maintained or save them if they have become forlorn, abandoned and left to the dark abyss of oblivion:
https://www.youtube.com/watch?v=UGU2DAWnOtE
|
|
|
| Edge Reading Disparities |
|
Posted by: Mike Brubacher - 05-01-2020, 09:58 AM - Forum: All About Edges
- Replies (4)
|
 |
Just received an email from a customer with a question. He just finished sharpening a blade and then garnered these three measurements at three different points on the edge: 90, 180, 220. He was wondering if his test methodology might be flawed.
First of all - even if one were intentionally trying to screw up the measurements, it's doubtful that one could produce this disparity in readings on a well ground and thoroughly deburred edge. Now, please don't take this as a challenge Exchange members! As a rule though, the statement is accurate.
90 - 180 - 220 do bear the mark of a wire (or false) edge however. In the first case (90), the edge had just enough structural stability to sever the test media cleanly. In the latter two measurements (180, 220) it didn't and either dented or folded the wire edge over before severing the test media. There could be other edge problems that could manifest in this manner but I advised the customer to look for a wire edge first.
Wire edges do make me think though. Usually, once a wire edge is removed, there is no significant reduction in sharpness. In the case of our customer, and once the wire edge is removed, he should end up with an edge that measures around 90. This leads me to believe that the width of the wire edge is about the same at the top as it is at the base where it will be separated from the newly created and structurally improved edge apex. So the problem with wire edges is that they are just "too tall" for their own good. So how's that for pure conjecture on my part? My mind is a terrible burden. I visualize microscopic things in dinner plate size and then draw conclusions. Those visualizations are sometimes later proven correct and sometimes not. I never reveal my batting average - too embarrassing.
|
|
|
|