The truth about Japanese chisels

while Japanese chisels as woodworking implements have existed for centuries it was perhaps the makers of the famed samurai swords that have given us the chisels that we have today in this video I'll share that forgotten story and I'll help decode the fascinating technology that make Japanese woodworking chisels so different from western style chisels by the end of this video you'll have a whole new respect for the strange little tool with the dented backside let's begin back in the days of the ancient Samurai a highly respected class of Warriors that are perhaps most recognizable to Western cultures today by their legendary swords the makers of those swords were as respected as the samurai themselves they dedicated their lives to their craft often employing secret forging methods developed and passed down over Generations apart from the nobility and the samurai themselves only the makers had sufficient status to legally carry these swords but that era came to an end when the samurai class was abolished in the latter half of the 19th century and facing the prospect of unemployment many of the Great Sword makers adapted their technology to crafting other tools including chisels that Heritage is one of the main reasons why Japanese woodworking tools quickly gained a reputation as among the best in the world the goal of the Japanese tool maker was to create nothing you see a Cutting Edge is the point where two planes meet in the case of a chisel you have the sloped bevel which meets the flat back to the naked eye that may appear perfectly crisp and sharp but if you were to zoom in with a microscope you'd likely see something like this a rounded overhead it might feel sharp but it's not perfect Perfection would require those two planes to continue past that blunt Edge theoretically the steel would get thinner and thinner until the edge becomes nothing at all getting as close to nothing as possible is what the Japanese Masters spent centuries developing materials and techniques to achieve if the steel was too soft it would deform and roll over along that microscopically thin Edge you simply wouldn't be able to get such a chisel as sharp as you could with harder steel but if the steel was too hard it would be brittle and that Ultra sharp but also ultra thin Cutting Edge would just crumble away finding the right Alloys forging using the right process at the right temperatures with the right tolerances is very precise work and while many of the Japanese chisels we find in woodworking supply catalogs today are mass produced rather than handmade one at a time by an old master much of the old technology still exists including some of the best steel out there Japanese tool steel is complex but for the sake of our discussion of chisels it can be broken down into two main types what's called white paper steel and blue paper steel the blue steel is the hardest it'll take the sharpest Edge and remain sharp the longest in fact there are variations of blue steel with different contents that are even harder including super blue that might take your Edge closer to nothing than any of the Old Masters ever dreamed but blue steel can be very expensive up to several hundred dollars a chisel for certain varieties and with that extra hardness comes some real downsides it can be difficult to sharpen and it can be quite brittle and prone to chipping so the edge doesn't last that may be fine if you work with a lot of soft Woods as they certainly do in Japan but for harder woods they require a slightly more forgiving steel that's why many of the Japanese chisels you find today are made from white paper steel now this is still quite hard compared to some Western chisels and again there are different varieties of white steel with different properties but it is generally easier to sharpen a white steel chisel than a blue steel one and while the White Steel may not take quite as Keen an edge as the ultra hard blue that edge won't be as brittle and short-lived of course when I speak of blue and white steel I'm not talking about the entire chisel blade Japanese chisels incorporate another bit of useful technology blade lamination if you look at the bevel you see two different colors the bulk of the tool is made from a softer steel while a piece of harder steel is fused to the underside during the forging process obviously this lamination technique saves cost and steel but that's not its main purpose some Japanese steel is so hard it may crack or shatter when you strike the Chisel with a hammer against a hard wood the softer body absorbs the shock while the harder Underside provides the superior Cutting Edge the Dual layers also make the Chisel easier to sharpen since two-thirds or more of the bevel is soft steel that is much easier to abrade with a stone than hard steel would be perhaps the most striking feature of a Japanese chisel though is the bag notice how it's dished out this is another bit of Technology with a specific purpose when you're pairing or mortising the back of the tool becomes your reference surface it must sit flat on the wood if there's a lump on the back of your chisel The Cutting Edge is not going to work properly with western style chisels we typically flatten the backs as soon as we get them out of the package that shiny flat surface doesn't have to extend down the entire back of the tool but an inch or so from The Cutting Edge will give you the reference service you need remember though that Japanese chisels particularly the backs of them are often made from very hard steel and sometimes it just takes forever to flatten the entire thing so long ago Japanese tool makers began intentionally creating Hollow or dished out bags this makes it possible to produce a flat reference surface around the perimeter of the blade if the area behind The Cutting Edge at the tip the two edges and to a lesser extent the heel are all on the same plane the Chisel will function properly with much less work but don't confuse this with this this was a new western style chisel I showed in a recent video about flattening chisel backs with sandpaper the back of that chisel was dished out as you can see by the dullness in the center after I rubbed it on a stone but that wasn't an intentional feature created by a manufacturer as it is on the Japanese version that Hollow was inconsistently formed remember I need a reference surface at the tip and along the edges and to a lesser extent the heel so as I try to gain that by rubbing the back on sandpaper to wear it down a bit the hollow changes shape it gets smaller but it still clings to one Edge that's because it wasn't consistently formed like the hollow on the Japanese chisel so I end up having to remove almost all of the hollow to establish my reference surfaces around its perimeter and the end I just decided to polish the hole back but that's not required with a Japanese chisel which has an intentionally created carefully centered and evenly sloping Hollow on its back with this I need only touch it up from time to time to be sure the perimeter on the hollow is flat and Polished now some people wonder what happens when the Tool gets shorter through repeated sharpenings of the bevel won't the hollow area soon Meet The Cutting Edge on the back it might but the precise consistent way that the hollow slopes away from The Cutting Edge causes it to shrink away from that edge as the back is worn down so if you do find The Cutting Edge getting a little too close to the hollow area rub the back on a stone and the hollow will Retreat away from The Cutting Edge again it's worth noting that the traditional way to adjust the distance between the hollow and The Cutting Edge was not necessarily on a stone but to periodically reshape the steel itself with careful and precise Hammer Taps that is a highly skilled technique that only the most dedicated users still practice handles of Japanese chisels are also unique they're typically made from Japanese red or white oak and they almost always feature a metal band at the end when the Chisel is new this band is left intentionally loose traditionally Japanese chisels are struck with a metal hammer called a gnome if you were to strike the wood alone it would mushroom and Splinter and eventually ruin the handle the steel band restricts any mushrooming effect to the very end so you have a pad to strike ahead of the band how much of a pad there is as a matter of personal preference and that's one of the reasons the steel rings are left loose so you can set them yourself I prefer about an eighth of an inch of wood protruding past the ring so this one had to be forced further down the handle there are two ways to do this I can compress the fibers by lightly tapping all the way around the handle with the hammer reducing its diameter so the ring can slide further on or I can use a tool called a ring setter this is a steel cup that slips over the end of the Chisel and forces the ring down the handle evenly and incrementally through Hammer blows if you buy a whole set of chisels you have several handles to do get a ring Setter it'll save you a lot of time and effort now once I have the protrusion I want I'll soak the end of the handle in water for a few minutes I had to sand the lacquer off the end of mine so the water could get into the fibers and make them soft then I use the hammer to shape the end mushrooming it over the edge of the Ring a little bit at a time working my way all the way around now I have a nice little pad to strike with my Gano without beating up the ring using Japanese chisels can be as simple or as complicated as you want to make it if you're used to western style chisels you can use a Japanese chisel in the same way I sharpen mine frequently with a thousand grit diamonds followed by a fair amount of strapping on both the front and the back if I can shave hair easily with it I can shave wood like butter too should you get some Japanese chisels for your shop not necessarily if you haven't like your Western chisels there's little you can do with these that you can't with those but most people who try Japanese chisels do seem to like them very much so take that for what it's worth I personally use my Western chisels most of the time but occasionally I pull out my Japanese set and I pretend I'm a woodworking Samurai if you're wondering what I use to get them sharp though check this out the mpower SPs sharpening station is an idea that was four years in the making designed to provide everything you need right in one place so you can sharpen and strap your tools quickly and get right back to work it begins with three Diamond plates there's 300 600 and 1200 Grit after sharpening you pop back on the magnetic strapping plates which are color coded to accept three levels of honing compound including eighteen hundred twenty five hundred and five thousand when your tools razor sharp everything including the compound sticks the lapping fluid it all goes back in the case you can even add a little honing jig in there if you wanted to it's really a great idea I like the Simplicity of it no more hunting around the shop for what you need it is all in one place in fact I think it'll be just the thing to take with me when I travel I like to carve when I'm on the road I've made plenty of videos about Diamond Stones in the past there are a lot of good Diamond systems out there and I'm not saying you should toss the ones that I've recommended before and buy this one but if you're looking for a new system or a second one for working outside the shop the Empower SBS system is something you should at least take a look at I'll link to it below this video

Channel: Stumpy Nubs

Views: 142,507

Keywords: woodworking, stumpy nubs, tips, workbench, table saw, scroll saw, drill press, quick tip, band saw, bandsaw, lumber, hack, hand plane, sharpening, tormek, worksharp, diamond stone, water stone, wood turning, bowls, lathe

Id: RlsBAXbufIs

Length: 12min 7sec (727 seconds)

Published: Fri Jun 09 2023