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Item 1. I hate sharpening knives and tools, so I wish someone would do a similar study for wood plane irons/blades (including their different steel types) versu
by hilbert42 4y ago
Item 1. I hate sharpening knives and tools, so I wish someone would do a similar study for wood plane irons/blades (including their different steel types) versus various grinding techniques, grinding grit sizes etc.; and also explain why good old carbon steel often gives a smoother cut than do many of the harder specialized steels that have Rockwell figures which are well into the 60s—even though the fact that carbon steel dulls and blunts much more quickly than do those much harder steels?
Item 2. In a somewhat oblique vein, during COVID I always wore N95/P2 masks in public and I always took extra heed to follow the instructions that came with them which read to the effect that 'this mask will be less effective on those with bearded faces'.
Clearly that stands to reason so the question is by how much.
I'm constantly bemused by the large percentage masks on bearded faces and whose wearers seem oblivious to the fact that their beards are likely rendering their masks ineffective. Especially so when I see doctors on TV who've beards and who are there specifically to proselytize the virtues of wearing masks. With their beards popping out from behind their ill-fitting masks, it seems strange to me that these highly trained medicos seem oblivious to the obvious fact that their beards are putting them at risk—not to mention that they are setting a bad example.
Now the issue is this: given that a clean-shaven, stubble-free face provides a better mask-to-skin seal than one with stubble, the questions are:
Does anyone know of whether tests have been done on N95-type masks to test the effectiveness of their mask-to-skin seals? If so, whether any significant leakage was detected at the seal and whether stubble growth throughout the day worsened said leakage (the implication being that by the afternoon/evening masks would be less effective though increasing seal leakage)?
The corollary of the question would be to ask if a beard stubble impedes the effectiveness of the mask-to-skin seal then at what point in the growth of a newly-forming beard (at what stubble length, etc.) does the stubble render the mask ineffective (dangerous to wear)?
- j-bos 4y agoNot sure where you can do it outside the industry, but mask fit tests are required in many (all?) US petrochemical facilities. The test involves an accurate measurement of gases passing through to the mask wearer. Edit: seems you can just buy a kit https://pksafety.com/3m-ft-20-training-and-fit-testing-kit-in-carrying-case?msclkid=cab35e8c5f5d169e47393db69ec42287&utm https://pksafety.com/3m-ft-20-training-and-fit-testing-kit-i...
- hilbert42 4y agoYeah, I'm vaguely aware of this and mask fitting for asbestos removal is almost mandatory in many workplaces. I suppose, given all the fuss over COVID, I've been rather surprised by casualness over the approach to mask-wearing given that the warning were there on mask packets before the pandemic. I would have thought this would have alerted many to the fact come COVID but seemingly not. BTW, my attention to detail seems to have paid off so far (I've not caught the disease as yet). Nevertheless, it would have been good to have been able to put some some figures to the practice rather than working anecdotally.
- GeneT45 4y ago>>I wish someone would do a similar study for wood plane irons/blades (including their different steel types) versus various grinding techniques, I think you're looking for the book "Knife Deburring: Science behind the lasting razor edge" by Vadim Kralchuk. The author had a good website, but it appears no more and my cursory web search indicates that he has passed away. He has / had a YouTube channel as well.
- hilbert42 4y agoThanks, I'll also keep an eye out for it. I'm not bad at sharpening plane irons and when I set my mind to it I can make them razor sharp—certainly sharp enough to shave with but I only test them by shaving the hairs on my arm and they do that very well. That said, most books on this subject only cover techniques and not the underlying metallurgy. The metallurgy is important but the problem that most of us encounter is that we plane users don't know what it is (as it's usually unspecified). Even if it is, it doesn't help much. Leaving aside badly-tempered steel (sharpened to red heat on a grinder etc.), some steels are just horrible to work with, I've some block plane blades made in the 1930s that have high tungsten content and they're almost impossible to sharpen well and even when razor sharp they don't cut well and it's never been clear why. Thus my comment about wanting to know more about the subject.
- GeneT45 4y agoA big part of the aforementioned book is the manner in which differing steels produce a burr, or even micro-burr that can be mistaken for an edge, but cuts poorly and/or deteriorates quickly. A number of deburring techniques are tested on a number of steels and it is noteworthy that there is no single best method - each category of steels responds best to a different manner of deburring. Great longevity was achieved with proper deburring (as shown in the book with a host of SEM photos. Excellent (aftermarket) plane irons of known alloy are widely available (at least here in the U.S.). I know some woodworkers value having all original parts, but if the primary goal is paper-thin even-width shavings it's hard to beat modern metallurgy.
- 4y ago