Terry, I think you should put that picture on your website with the caption - "A well sharpened chisel will give a much cleaner cut". J (that's coming from someone who has sliced and diced himself too!) I have a couple of Japanese paring chisels very much like yours. Sharpened on a good set of Japanese waterstones, they take a fearsome, mirror edge and will cut so cleanly that they will leave a burnished surface in the maple. The blade portion of the laminated chisel is made of very hard steel - on a really good Japanese chisel, it will be 64 to 66 on the Rockwell C scale, which is about as hard a steel as we can get for edge tools. Steel this hard is also quite brittle, which means it is prone to chipping and or even breakage. Which is why it is laminated to much softer steels for the shank of the chisel. These steels are more flexible and less prone to breakage. Thus the combination of the two steels in a lamination gives the best of both worlds. So these quality chisels will never be a "bung" chisel and using it as such will tantamount to "tool abuse". I have my "s..t chisels" to be used with reckless abandon. Sharpening a chisel well means sharpening BOTH sides of the chisel, always keeping the edge at a consistent angle as you sharpen, and using a progression of stones with ever finer grits. If you were to look at a chisel edge under sufficient magnification, you would see that the edge would not be a single straight line, but rather look like a rough series of large serrations. Moving the chisel over the stone, reduces the size of the serrations as you progress up in grits. Even that mirror edge will have serrations, but they will be very small. My stones go from 600 grit to 8000 grit. There are some ceramic stones that go up to 30,000 grit. You learn to sharpen by understanding proper technique and practice, practice, practice - it is an acquired skill Will From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Terry Farrell Sent: Saturday, October 09, 2010 7:18 AM To: pianotech at ptg.org Subject: Re: [pianotech] Of Chisels I honestly haven't noticed a huge difference between cheap and good chisels regarding their ability to acquire a sharp edge. How long that sharp edge will last is definitely related to quality of metal (the harder that longer-lasting - but also the more difficult to sharpen). I know that you need to have a proper angle for a good wood edge (and sorry, without looking at my notes on my Tormac I don't know what they are right off hand). Now maybe my "cheap" chisels are not REALLY poor quality. I have to admit that I do have several REALLY cheap chisels that I use for nasty work - hammering on stuff with nails in it, chiseling concrete, etc. And I also have to admit that I have tried to sharpen these chisels and they never do seem to get a really fine edge on them. Perhaps we need a metallurgists input, but my understanding is that some metals are finer "grained" than other metals (well, steels) - the finer the "grain", the sharper the edge attainable. I'm not a metallurgist and I don't know exactly what metal "grain" is - particle size presumably. I know metal doesn't have annual growth rings, and I've never really seen metal "grain". But it only seems reasonable that some metals (steels) are going to produce a finer/sharper edge than others - and presumably more expensive metals would be the finer "grain" metals. I presume this issue of steel "grain" size is the biggest difference between good and cheap and the ability of a chisel to be more finely sharpened. The best chisels I have run across are Japanese laminated chisels. Del Fandrich turned me on to them when I asked him about a chisel for bridge notching. The laminated chisel has two metals of different hardness - a very hard metal on the lower surface (where the tip of the blade is) and a thicker softer metal on the top. The reason they laminate two metals together is to give you a blade of adequate thickness (stiff, feels good, etc.), is easy to sharpen (soft metal grinds quickly and hard metal is so thin that it is not time consuming to sharpen) and holds a sharp edge for a long time (hard metal is at blade tip - hard metal holds sharp edge for long time). Bottom line is that I do believe that "good" chisels are better than "cheap" and worth it for the professional woodworker. My Japanese chisels are like these Usu Nomi - Japanese Paring Chisels: http://www.fine-tools.com/usu-nomi.html I can get these things so sharp it's scary....... Hope this helps. Terry Farrell On Oct 9, 2010, at 5:11 AM, David Boyce wrote: Speak to me of chisels, folks. What makes them able to take a good edge or not? Over the years I've bought "bargain" chisels, and sharpened them to what felt like a good edge, only to find that they wont cut wood by hand unaided but have to be battered with a mallet. it daunts one's confidence. The other day I was enlarging a mortice in the front door of my mother's house so as to fit a new lock, and as ujsual was struggling with a cheap chisel. Then I dug out a couple of my late father's old chisels, very churned-up at the tip, but a decent make (Marples) and sharpened them, to find that they cut well. What is the difference in the metal? Why don't some cut even though they feel sharp to the finger? Many years ago, back in nineteen-canteen in High School, I got an A in the woodwork exam. But we were never initiated into the myteries of cheap v. good chisels. I await pearls of wisdom, knowing that on this list i am bound to get 'em.... Best, David Boyce. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20101009/af94b5ec/attachment-0001.htm> -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: image/jpeg Size: 71989 bytes Desc: not available URL: <http://ptg.org/pipermail/pianotech.php/attachments/20101009/af94b5ec/attachment-0001.jpeg>
This PTG archive page provided courtesy of Moy Piano Service, LLC