[QUOTE=Tom M King;3039945]I use single bevels, and flat backs, nothing else. My two helpers, that can almost read a tape measure when they work together, and anyone else, can get a super sharp edge. None of my plane irons, and few of my chisels, have seen a grinder in years.[/QUOTE]
Tom, I respect your experience and I'm interested in your single bevel techinque. Personally I've always use the primary (25°) and secondary bevel (30°) technique. Admittedly having to periodically re-grind the primary bevel isn't desirable and I can see how your approach might have advantages. The simplicity and repeatability of your approach are appealing. Anatomically and technically, maintaining a single bevel angle seems pretty easily doable freehand.
Conceptually I would think the drawback of this approach is you have to remove a lot more steel off – the entire bevel of the cutting iron versus the much smaller secondary bevel. If you don't mind me asking, what are the stones/grits you use and how long does it take you to achieve a sharp edge?
I hope my questions doesn't, cross as pushy. I'm sincerely interested in learning from your experience and appreciate you taking the time to share your insights.
All the best, Mike
I made a video a few years ago, using a kitchen sink in a house we were working on. I have a dedicated sharpening sink, but if there is a sink to use, and some counter space, I'll use that. In that video, I took a chisel that had been used for scraping paint off of brick, to super sharp, in a little over four minutes. That included talking, flattening every stone, and fumbling with the camera. Without having to think about talking, or fumbling with the camera, time would be about half that. For that one, it started with 400, then to 1,000, 3k, 6k, 10k, 13k, and finished on diamond lapping film on a granite surface plate.
There was much gnashing of teeth, and chest thumping about how stupid I was, and how much water I was wasting (I sharpen under running water, but here, water runs out of the ground every few hundred yards). There is no stone soaking, and with the synthetic Sigma stones, no need to bother to raise a slurry. A stone goes under a small stream of water, and goes to work. If I'm in the middle of a planing session, typically, I'll start at 6k, and go up.
These days, there are a few other stones between some of those. I'll use a grinder is there has been damage to an edge, but not for any other reason.
There is not much steel to remove. It only takes a half dozen strokes on each stone, and the stones are right there, in a rack behind the stone holder on the drainboard. The stone holder does not get tightened on each stone. It's set large enough that the largest stone goes right in.
I sharpen by feel, and never look, or feel for a burr. You just push a little harder on a full bevel, than a microbevel, but it's not something that I even think about. I don't think the total number of strokes varies much. With a guide, you're not really dropping the level of the whole bevel evenly. The cutting edge gets microscopically more taken off at it rotates down through the radius from the roller to the edge.
Time saved is not having to regrind, and I don't grind in the old houses I work on anyway, so that would require a trip outside.
The only sharpening I do are the plane irons that have cambers. I hire people that no one else will, and those guys do all the other sharpening.
I made jigs that are quick and easy to set the exact angle with, and use a guide. I had to cut the number of steps in the system to an absolute minimum, and eliminate any skill required.
I sharpened freehand for probably 30 years, after using a guide for maybe 10, before I went back to a guide, so the guys could do it. They're hopeless freehanded.
I'm not saying the system is best for everyone, or even anyone. It suits me just fine though. We probably hand plane more square feet of wood, and use sharp chisels for many more things than any hobbiest woodworker, and probably the vast majority of pros too. I don't do woodworking for a hobby. We work on 18th, and 19th Century museum houses, and match old work surfaces as closely as I can.
I have never used the ruler trick, and never will. It always seemed like something needed if you couldn't get the edge sharp without it.
Last edited by Tom M King; 07-24-2020 at 7:49 PM.
I am far from a sharpening expert but I think I have something to add here. I started with microbevels and the ruler trick because that was the first info I found when I started. Once you start down that road it’s hard to go back, especially since I did have a grinder*. If I wanted to move to a flat bevel or a flat back to a plane blade it would take a lot of work on a diamond plate. Just never wanted to do that.
Also, I spent a lot of money on premium tools (don’t have much else to spend on) and they almost universally came with a microbevels — can’t think of any off hand that didn’t. Even if I had wanted to flat bevel it, I would have had to address the microbevels that came on them.
*with more shop space I have finally ordered an 8” grinder.
Clifford, the ruler trick does NOT replace flattening the back of plane irons. You still need the last inch flat (maybe half-inch with premium irons), to remove machine marks, take out any belly or bow, and get to a little mirror finish. Then, the ruler trick allows you to only repolish the last mm or so. Eventually, though, when you regrind, you're going to need the back to be flat.
David Charlesworth will be making an appearance tomorrow (Saturday) during the first 30 minutes of Rob Cosman's Q & A Session on YouTube. I'm sure the topic of sharpening and his "ruler trick" will come up.
Makes one wonder....how many bevels are in the razor one shaves with in the morning has......
Question was more about "Why" 3-4 bevels, than "How"...wasn't it?
Edited** - didn’t realize this was posted last night...
Just in case anyone wants to know first hand, tune in tonight to Rob Cosman’s YouTube live at 6pm Eastern. David Charlesworth will be his special guest. He intends to talk about how the “ruler trick” was developed and the why behind it.
My plane irons are hollow ground and honed on a diamond hone. You only hollow grind one time.
The amount of steel removal is often stated as an advantage of using secondary (and multiple) bevels.Conceptually I would think the drawback of this approach is you have to remove a lot more steel off – the entire bevel of the cutting iron versus the much smaller secondary bevel.
While the area of the surface worked is larger on a flat bevel, isn't more metal removed when the primary bevel needs to be reestablished when using secondary bevels?
Wouldn't this much of a bevel on the back of the blade cause problems with a chip breaker.Then, the ruler trick allows you to only repolish the last mm or so. Eventually, though, when you regrind, you're going to need the back to be flat.
Then if regrinding requires a flat back isn't it making more work in the future to save a little time today?
What comes to mind is the desire for quicker blade sharpening may actually be leading to more time needed later when a blade needs its primary bevel reestablished or the back flattened.
During my work doing machine maintenance much of my time was spent cleaning up problems left by others taking short cuts to save a minute or two. It seems a lot of the 'tricks' to make blade maintenance quicker may be a false economy in the long run.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)
Jim,
This is a quote from a recent email from Stan Covington about multiple bevels and the "ruler trick": "...It certainly makes the teacher selling classes and books and videos look like a genius (and make money), but it cripples their students from becoming truly proficient..." I couldn't agree more.
ken
Was starting to be just another "Sharpening Thread"....