Contributor
Is there a standard as to how many angels can dance on a tertiary bevel before a blade needs to be reground or is it when the tertiary bevel fully overlaps the secondary?
These are the kinds of pondering that might keep me up at night if it weren't for being satisfied with a flat as possible bevel, as long as it cuts as well as possible or needed with my skills.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)
Member
As for the ruler trick and causing issues, I have never experienced any. The small amount that you are polishing/sharpening/etc on the back will be eliminated once you go back to grind the primary again. So, when I sharpen, the Rob Cosman way, the primary bevel doesn’t get touched. You find the primary, lift up a little and polish just the leading edge. Then, on a finer grit stone, you make an even smaller bevel by lifting up just a bit higher than the first time. Once that secondary bevel gets “too wide”, you go back and regrind that secondary out. This in turn, eliminates the bevel on the back of the blade that you made with the ruler trick.
Just my two cents and the way I was taught by Rob. Not the only way to sharpen at all, just what I use.
Contributor
You mean where everything is black and white, there can be nothing in the middle? Yep. Always happens here.Originally Posted by steven c newman
~mike
happy in my mud hut
Contributor
there can be only one (in voice of the Kurgan)
Contributor
"My Sensei will beat your Sensei..as only mine follows the One True Path...Hahahah"
We have work to do....
Estate Sale 2, Jack plane.JPG
(iron still has the Factory Grind...can't have that, can we?)
Member
The purpose of sharpening anything by any method is to get a tool ready to do work. Rob Cosman is an extraordinary craftsman, and I don’t think he owns a ROS-the final tool to touch his work is his hand planes. Is his method of sharpening for everyone? Perhaps not, especially if one is producing period pieces and/or restoration work. But for those of us who do woodworking for a hobby, and are looking for creating the best quality work that we can... If you have a process that works for you, perfect, but unless one is already producing work with the same level of quality as he does, perhaps we should also respect his process and not mock it.
Contributor
One of my reasons for often advising folks to work with what works for you.The purpose of sharpening anything by any method is to get a tool ready to do work.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)
[OP]
Member
So much wrong it is hard to unpack. Yes he is a good craftsman but he is also a salesman selling tools, classes, and videos. I do not have to produce work at the same level as Cosman to recognize BS when I see and hear it. As a good friend put it, folks like Cosman, he is not the only one, advocate shortcuts not because they are better but are easy to teach and can help sell whatever they are selling. On the video in question there were several statements by Cosman that were wrong, I haven't the time or interest to go back and make notes but they are there and if you watch carefully you should be able to spot them as well. And no I do not have to respect his process and yes I can mock it where wrong.
ken
Member
Help me understand, if he gets better results than you with the methods that he uses, then how are his statements and his process wrong? What is it about your process that is superior if your results are, by your own admission, not as good as his? BS meter tripped here also.
Contributor
For me it is where he is demonstrating the ruler trick. At around 15 minutes in he states it saves one the trouble of having to flatten the whole back. What is wrong with holding only the 1/4 - 1/2" from the edge flat on one side of the stone and polishing it without a ruler?
Wouldn't this be the same as the ruler trick without the ruler?
Also like fingernails to me is recommending removing the burr only on the finest stone. Maybe this is fine with a very light burr when one is only using two stones. A heavy burr can leave some nasty scratches on a fine stone.
Maybe for folks who really hate spending time sharpening all of the different tricks to speed up a process are a God send. For me sharpening is a pleasant few moments of listening to music and restoring the edge on a tool for working wood.
Even when working on a project for commission or to sell, sharpening is not a big consumer of my time.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)
Contributor
Do you feel the final result is all due to a sharpening method?
In the video he is showing off a fine shaving which he claims is about a half a thousandth of an inch. My sharpening method has been able to produce a shaving of a quarter of a thousandth of an inch:
Fine Shaving 0.0002x?.jpg
This only means my sharpening process is able to create a keen edge. It in no way elevates me to a better woodworker than anyone else.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)
Contributor
I’ve been around this work for a while. The ruler “trick” has been around longer than I am old. Maybe not with a ruler but similar things. When I learned to sharpen it was very common for a craftsman to take the last stroke across the edge of his carborundum stone. Some raised the back of the iron a small amount “ruler trick” some kept it flat but because the stone was dished a bit there was a sharp edge on the stone. I was taught to raise the handle a bit for the bevel side of the chisel for the last few strokes. Some used a strop after, others used their hand (most were leathery). I never saw a plane iron with the back shiny more than an inch or so. The same with chisels. Don’t know how they ever accomplished a thing with those dull tools😀. Nothing new under the sun, just reworded some. Just how many plane irons and chisels have you found used with backs completely flattened?
Last edited by James Pallas; 07-26-2020 at 6:32 PM.
Member
Seems like that could present a challenge as the blade wears. If you are moving it back ¼” on each sharpening, eventually there will be a bump to deal with. The ruler trick is so minuscule, less than a 1* bevel on the blade, and it maintains that 1* bevel with each sharpening.
He is only using two stones, and with the ruler when the burr is removed, the edge of the blade is off the stone. The burr peels away as soon as it hits the edge of the stone.Also like fingernails to me is recommending removing the burr only on the finest stone. Maybe this is fine with a very light burr when one is only using two stones. A heavy burr can leave some nasty scratches on a fine stone.
Member
I believe the final result is because he is an excellent craftsman, and part of that is due to his willingness to explore different methods and apply the results to his process. Certainly there are other parts of his process that people are calling out in this thread, such as his process of dealing with tear-out by closing the mouth of the plane rather than adjusting the cap iron. The cap iron the prevalent means to deal with that problem today, but there is no question that he gets excellent results adjusting the frog.
Again, I’m not saying the Cosman way is the right way or the only way, but I do believe he has proven in his videos that his methods produce excellent results. Why do people feel it necessary to give him crap for that, just because it’s not the method that they use?
Contributor
So, to each his own then, right?
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