Single-Bevel Sharpening on DMT DuoSharps

[sdbranam]

I know some of you chaps here are so bored with sharpening you've probably keeled over asleep on your keyboards, but for those still awake, here's a blog post with video where I tried out Mark Rhodes' sharpening method as he described it on another thread.

http://www.closegrain.com/2012/08/single-bevel-duosharp-sharpening.html

Not sure I got it down exactly the way he does it, but it worked very nicely, another method for the arsenal.

 

[Derek Cohen (Perth Oz)]

Hi Steve

I suspect that you have just created the most time-consuming sharpening method ever. I'm afraid so.

Let's see if I have this correct: you have attempted to emulate Mark, who says a single bevel method s faster (than what you were doing). However, while Mark was freehanding on a hollow ground bevel face, you instead maintained a totally flat bevel face?

If you honed a flat bevel face, then you would have been working at least 5 or 6 times the amount of steel than on a hollow ground face.

The advantage of a hollow ground face is that you reduce the steel on the bevel face to two thin strips at either end. Hollow grinding is particularly suited to freehanding, as you can use the hollowed face as a jig.

Flat solid steel faces are best used with a secondary micro bevel (to reduce the steel area).

Do not confuse a Japanese blade with the solid steel face. The Japanese blades have only a thin layer of hard steel and are backed with a thick layer of soft iron (to absorb vibration). They hone quickly on a full face as the iron abrades easily.

The absolutely best method of honing a blade ensures two things: firstly, the blade gets sharp quickly. Many methods can do this. Secondly - and in my opinion, this is the important one - the method must allow the blade to be re-honed just as quickly. In other words, your aim is repeatability.

I hollow grind on a Tormek. This has an advantage of creating a hollow to the edge of the blade without threatening damage by heat. I then freehand on the hollow on waterstones. The resultant microbevel is small, and the angle is repeatable.

Regards from Perth

Derek

 

[sdbranam]

Hi Derek,

Yes, I'm aware of the two-layer construction of laminated Japanese blades. Jim Kingshott's book "Sharpening" does a nice job of describing how a single bevel is used on them because the bulk of the material is softer steel that abrades quickly, and only a thin layer of hard steel forms the cutting edge. He also mentions knowing several craftsmen who use a single bevel on western tools. Toshio Odate in his book says one must never do anything other than a single bevel, but of course he's referring to Japanese tools.

I'm also aware that Mark does some hollow grinding. But the time required is the time you saw in the video, which is no more time-consuming that any other method; timing the video, I spent 22 seconds on the plates and a further 22 seconds on the strop. I also found I could reduce the stropping a bit and still get an edge that performed as well, so 30-45 seconds total. I went through several cycles of sharpening and using to practice, and the resharpening was always fast, despite the larger surface area being sharpened. The coarse plate works fast. I did initial shaping on an extra-extra-coarse plate to establish the overall flat bevel; once established, it's not time-consuming to maintain.

While a hollow-ground surface will give better absolute repeatability of the angle, this was repeatable within a reasonable tolerance, though you and I may disagree on what a reasonable tolerance is. As far as speed to resharpen and obtain a sharp edge, it was quite repeatable.

 

[Jacob]

Hi Derek,

Yes, I'm aware of the two-layer construction of laminated Japanese blades. ......

A lot of old British blades (most of them?) are laminated too. Must speed up sharpening a touch but by and large you wouldn't notice.
I don't rate hollow grinding. What's the point of having a thick blade and then grinding it thin? Much better to have a flat or convex bevel with more metal behind the edge.

 

[Derek Cohen (Perth Oz)]

Jacob! How nice to hear from you! I'm well thanks. You too? Nothing seems to have changed.

Regards from Perth

Derek

 

[Jacob]

Jacob! How nice to hear from you! I'm well thanks. You too?

Hi Derek, fine thanks, glad you are too

Nothing seems to have changed....

True. Why would it? :lol:

 

[sdbranam]

Meanwhile, for those who truly object to the single-bevel shown here (and the previous convex methods I've shown), two more upcoming will be double-bevel on waterstones, and hand-cranked hollow-ground on (not sure which abrasive I'll use).

Then the menu will be complete! Or at least as complete as I have in mind for now. If you compute the total number of combinations of abrasive type, bevel shape, grinding motion, strop or not, pastes, etc, there are probably more possible combinations than woodworkers!

 

[Paul Chapman]

the time required is the time you saw in the video, which is no more time-consuming that any other method; timing the video, I spent 22 seconds on the plates and a further 22 seconds on the strop. I also found I could reduce the stropping a bit and still get an edge that performed as well, so 30-45 seconds total.

I'm afraid I find the examples people quote of how long it takes to hone a blade somewhat pointless. Surely it all depends on how blunt the blade is? If you re-hone as soon as the edge starts to go off, then most methods will be fast. However, if you keep planing until the blade is well and truly blunt, then it's going to take a lot longer.

You are obviously able to compare the various methods you use but it's all rather meaningless for the rest of us.

How hard is it to hone a blade anyway :? :lol:

Cheers :wink:

Paul

 

[woodbloke]

Do not confuse a Japanese blade with the solid steel face. The Japanese blades have only a thin layer of hard steel and are backed with a thick layer of soft iron (to absorb vibration). They hone quickly on a full face as the iron abrades easily.

Derek

Lots of first class stuff here from Derek of Oz, as is to be expected. I use Japanese chisels exclusively which I hone with single bevel, as Toshio Odate recommends and the reason is that there's more of the soft iron back (with a flat bevel) behind the hard steel compared to if it's hollow ground...where conversely there's less. The problem with producing a repeatable single bevel is that over time, minute variations in the honing angle (and arm position) may gradually make the blade go out of square (unless you're very careful)...plenty of examples on ebay, so this is where the repeatability of a honing guide or jig pays dividends.
I use the Kell III with 3M films from WH and I just swipe a few times on each of the films starting at 40 and finishing with 1 micron and a pass over the strop with some green goop on it...works for me - Rob

 

[mtr1]

Thanks for giving it a go (though I know it's not my method), my old foreman taught it to me as did my grandfather allude to this method, and both master cabinetmakers in the trade for a combined total of a 100yrs. Might be an old price/pro way of not spending much time sharpening and getting on with the woodwork. I wouldn't bother with the black stone unless you have a chipped iron, it just adds another step. Just re-grind, I think the red is coarse enough.

I should add this is a quick method to enable you to crack on with the work, not one that will make your chisels/plane irons outlast you, my clients pay for my new tools not me. I still have my first set of chisels (but don't use them anymore), but I'm on my third plane iron for my smoother.

I would start with a hollow grind (thats the important bit as Derek said), straight onto the red, then a fine slate or whatever the finest stone you have, then strop, and thats enough with the timbers that I use. You still seem to have ended up with a convex bevel, that would of got me a telling off from the foreman, I think you should start with a hollow grind, not right to the edge, leave a 1 mm strip of your old hone top and bottom, then try it again. I sharpen often and quickly when I'm doing a lot of hand work, and I don't worry if I re-grind on the same day. Cheers

 

[sdbranam]

How hard is it to hone a blade anyway :? :lol:

And yet it's the subject of constant vexation for beginners just learning the skills!

Thanks for the info on hollow grinding, I'll integrate that into my post on it. That was actually the first method I ever learned, from David Marks' TV show "Wood Works". But I didn't have access to a grinder or any nice sharpening stones, and I was just starting to get over that conceptual hump of "What do you mean I have to keep sharpening this stuff all the time?" And of course when I finally did get a power grinder, the first thing I did was burn the end of the tool.

But they're all learning lessons. Sometimes you have to figure it out one mistake at a time.

 

[sdbranam]

Surely it all depends on how blunt the blade is? If you re-hone as soon as the edge starts to go off, then most methods will be fast. However, if you keep planing until the blade is well and truly blunt, then it's going to take a lot longer.

You bring up an interesting question. Paul, how long do you go before resharpening? I've seen people recommend frequent resharpening before it turns into a major job. There's always the balance between taking up too much time constantly interrupting the work to resharpen, and waiting so long that a blunt edge is slowing your work. Again knowing when to sharpen is a skill developed through experience, but what advice would you offer someone trying to gain that experience?

There have been plenty of times where I've put it off, then once I do it and get back to work, realize I should have done it much sooner because the tool is performing so much better.

 

[sdbranam]

And meanwhile, I've updated this post to indicate that I didn't get it right, as well as adding Derek's warning about not confusing this with Japanese tool single-bevel sharpening. Hopefully I'll get it right when I cover hollow-grinding!

 

[Jacob]

.... what advice would you offer someone trying to gain that experience?....

I'd say if you feel it might need sharpening then do it now. That is assuming two things; first that the operative is actually engaged in active woodwork and not just tool fiddling, second that he has a quick and easy working system and isn't into crazy sharpening.
"Feel" is the operative word - you need to get a feel for it.

 

[Paul Chapman]

Paul, how long do you go before resharpening?

I've no idea - it all depends on the abrasiveness of the wood.

Rather than agonise over what method to use for honing, I think it's far better to concentrate on how your planes are set up if you want to work efficiently and effectively. If you do all your planing by hand (as I do), then you really need several different planes set up for specific tasks. In my experience, scrub planes, toothing planes and those with a steep camber used for bringing the work roughly to size, don't need the same level of sharpness as those used for jointing, smoothing, shooting and scraping. The latter ones should, of course, be super-sharp but that's not difficult to achieve.

In my experience, once you realise that the way you set up a plane is more important than the method you use for honing, a lot of problems disappear.

Cheers :wink:

Paul

 

[sdbranam]

I've no idea - it all depends on the abrasiveness of the wood.

Rather than agonise over what method to use for honing, I think it's far better to concentrate on how your planes are set up if you want to work efficiently and effectively. If you do all your planing by hand (as I do), then you really need several different planes set up for specific tasks. In my experience, scrub planes, toothing planes and those with a steep camber used for bringing the work roughly to size, don't need the same level of sharpness as those used for jointing, smoothing, shooting and scraping. The latter ones should, of course, be super-sharp but that's not difficult to achieve.

Ok, I didn't ask that clearly. I didn't really mean "how long" in terms of actual time, but more in terms of what makes you decide, given the abrasiveness of a given piece of wood, that you need to resharpen? Is there some feedback you get from the quality of the cut, the appearance of the surface, the feeling of the plane, that tells you it's time? And what about with chisels? I realize this is probably mostly a matter of judgement, not necessarily something that can be put into words.

I also do all my planing by hand, and I wait a long time before sharpening my scrub and cambered Stanley #5, since I'm using them for rough work. My Lie-Nielsen #7, which I use for jointing and shooting, and #4 for smoothing, I sharpen much more frequently, but I always find that after I do, I feel I should have sharpened sooner. I also have Stanley #3 and #2 for smoothing, though I use them much less frequently.

 

[mtr1]

I don't know about Paul, or the others, but I can hear when a plane needs re-sharpening. Chisels, if they require a bit more than a gentle push(when paring), then back to the stone.

 

[Paul Chapman]

As Mark says, a plane with a sharp blade sounds quite different from a blunt one. But hand woodworking is such a tactile thing that it's easy to tell when a tool is not cutting as it should by the feel of the tool, the effort it takes, the look of the shavings and, most important perhaps, the quality of the finish.

Of course, all this talk about honing begs the question 'how sharp is sharp?' One of the best tips I picked up was from Garrett Hack and that's to finish your blades on a block of wood with diamond paste or metal polish (I use Autosol metal polish). That will get them really sharp. You can see a demo here http://www.finewoodworking.com/SkillsAn ... x?id=28819

Cheers :wink:

Paul

 

[Derek Cohen (Perth Oz)]

Hi Paul

Better than Autosol, try the diamond mesh from LV in 0.5 and 0.1 microns. These will last a very long time. A couple of swipes on each grit, and you will be amazed. The 0.1 take the edge to a level you could only before dream of. And, incidentally, hardwood for diamond paste is a poor substratum.

I use the 15, 3, 0.5 and 0.1 as my travelling system.

http://www.inthewoodshop.com/WoodworkTe ... dFilm.html

Regards from Perth

Derek

 

[Paul Chapman]

Hi Derek,

Thanks for that. Looks good. However, all honing methods are a bit of a compromise and there's always something 'better'. While the LV mesh is no doubt excellent, I think I'd find it all a bit of a faff. The diamond paste or Autosol on a piece of wood does everything I want and is simple, fast, inexpensive and fits well with the way I work.

Cheers :wink:

Paul