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)?
>>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.
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.
A 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.
That's interesting, especially if it has info on ways of identifying steels where micro-burrs really aren't very controllable. One does everything correctly (I even use a lab microscope occasionally) and with some steels micro-burrs sort of flake off irrespective of the method of sharpening and or steeling them.
Some steels are just horrible and tempering and hardness are not necessarily good indicators of quality. I have a few chisels that superficially seem OK and the steel is hard and takes a good edge but five minutes later they're useless, others, sometimes even cheaper ones, turn out to be excellent.
As a techie who like playing with tech toys I thought of using a handheld x-ray fluorescence spectrometers like, say, this one: https://alloytester.com/xrf-steel-tester. There are any number of them around these days but they're expensive even to hire and I can't really justify one just to indulge my curiosity. However though, it would be really nice to go around testing everything that has an edge and logging its alloy properties against actual performance tests. Perhaps some day.
I couldn't care less about original parts (they're tools!)—so long as the tool works well (I don't for a moment consider myself a collector of old tools). That said, when making repairs I'll go to some trouble with old tools to match a tool with its 'correct' parts if possible (but ultimately it's a pragmatic decision—if I don't have the correct part I'll use wherever is to hand or what works best). By that I mean if it's possible to mate together a tool with parts from the same manufacturing source and same era then I'll do. For example, my No. 8 Stanley somehow lost it's lever cap during a move and I had access to several others that would fit but I selected one that came from the same factory and manufactured around the same time (in this instance the plane was of US manufacture/New Britain and made in 1933, so it received another lever cap from the same factory made in the same era (it was of the first generation to use the kidney-shaped slot for the cap's screw). I'm in Australia, so I had lever caps manufactured in the US, UK and here (including UK Record parts) to choose from. Nevertheless, it now has a plane iron of modern manufacture (but I've kept the original one and it's identified as belonging to said plane). There's also another reason to match parts which is that they usually fit better (leaving Bed Rock planes aside, I'm also of the opinion that the best consistent run of 'normal production' planes Stanley ever made came from its US plant and were manufactured between 1933 and about 1941 (the run came to an end when war regulations kiboshed the quality).
I do have a sense of history when it comes to these old hand-tools, my No. 8 is now 89 years old but it's not the oldest, that accolade goes to my No. 45† which dates from 1907. I'm of the opinion that we never actually own these objects, we're just their custodians for life—after all, my No. 8 is still in excellent condition (so are several others which are older), and if looked after with a little care, it'll still have several human lifetimes left in it after I'm gone. BTW, its original owner wrote his name on a piece of paper and dated it then put it in the space under the plane's tote (I'm now very curious to know who he was but I've really no idea). Anyway, that piece of paper stays with the plane (I've really no right to remove it).
Incidentally, I have a copy of Antique & Collectable Stanley Tools - A Guide to Identity & Value - 1996 edition by John Walker. You're likely already aware of it but in case you're not, it's an absolutely invaluable 880-plus page tome on the subject of Stanley tools, there's nothing else its equal. It's the ultimate bible for not only collectors but also for anyone who fixes or refurbishes these tools. There's a new edition out which I've not yet seen (it was out of print for quite some years which made secondhand copies of it much more valuable than many of the tools mentioned therein).
Back to plane irons, I use this mob from time to time for replacement irons but they're expensive here where I live. They are reasonably consistent and work reasonably well but I'm not altogether totally happy with them (it's what I now use in the No. 8, No. 4, 5 etc.): https://www.ibctools.ca/product-category/ibc-blades/. They'll also do paper-thin shavings but that's usually of secondary importance—for me, a steel that keeps a keen edge for the longest duration ranks first (these come close but I've had irons that cut somewhat better).
Thanks for your comment.
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† Damn monstrosity of a thing it is, the only thing I can imagine that's worse would be a No. 55.
Not 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-i...
Yeah, 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.
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)?