This means the edge is extremely sharp but it's not as durable. First, it will never destroy a tool due to overheating (which can happen with electric grinders). 1. Because the bevel is on the inside, I’m not sure how to sharpen them. As long as some of the original hollow grind is left, I keep honing without regrinding. I mean, from left to right at the cutting edge only - maybe a 1/16". Besides, the edge might be weaker but stays thin for much longer. The body of the blade is made of soft steel and the tip or the edge is made of high carbon steel which is a hard coating. Second, I use the diamond stone to fl at-ten the waterstones. What it is: A chisel grind essentially is a V-bevel, except that only one side of the blade is sharpened while the other side remains straight (like a wood chisel). Hollow Grinding: Necessity or Relic? I use a 6" wheel driven by a 1725 rpm motor with a 2:4 pulley set up to cut the speed in half. Narrow chisels and thinner plane irons will need hollow grinding more often as the shiny areas at tip and heel will meet after fewer honings, but some of my larger blades can be honed many times in between grinding sessions. Using a high speed bench grinder with a Norton 3x 46 grit stone, to grind a chisel freehand. What it's good for: Woodworking, food preparation. The school I'm attending teaches hollow grinding for both plane blades and chisels. Chisel ground blades have a repuation for low cutting performance as they often have thick edges and obtuse edge bevels, as well as very thick stock width to blade length ratios. There’s really no point in flattening the entire back of the chisel, it’s just wasted effort. The hollow grind is the best choice for a fixed hunting knife by me. I also find it a necessity to hollow grind all blades. Japanese tools and Western mortising chisels should not be hollow ground. The Hollow Grind . Flat Grind. Like the hollow grind, the two edges curve to meet each other. It takes me more time to get it locked in the chuck than to sharpen one chisel. A Hollow Grind is found on a knife like the Buck Woodsman because it's ideal for skinning. Many modern makers utilize compound grinds for both their functional and aesthetic merits. Often the angle of the bevel for chisel ground blades is slightly more obtuse (25°-35°) to create a more durable edge. Full Flat Grind . I would be hesitant to hollow grind any chisel that you primarily strike with a mallet, just my opinion. Part 5: Grinding the Hollow. Chisel grind creates a sharp edge but requires constant maintenance due to the single bevel. You learn about variable speed grinders, using an effective tool rest and how to set it up to grind the correct angles. Many cleavers and butcher’s knives also use this grind. The first is the Full Flat Grind. One of the primary advantages of the hollow grind is that the chisel almost locks into place because there are only two points of contact I gently pull back on the chisel four or five times and look for the small bevel forming at the two points of contact. The next step is to get rid of all the grinding marks on the outside of the chisel. I hollow grind all my chisels (choice of high speed grinder or hand cranked wheel), then freehand them on waterstones. A Simple Hollow Grinding Jig: This is a jig I threw together from things in my shop that makes it easy to create hollow-ground knife bevels. The chisel grind features a full 90 flat on one side with a grind of any style on the other side. Cabinet making chisels on the other hand get a hollow grind using the grinder, then a honing through various grits of silicon carbide paper on glass. I typically grind using a diamond stone for three reasons. See more ideas about belt grinder, knife making, grind. These chisels benefit from a flat bevel due to the abuse they take when chopping. Single-bevel sharpening on Duo-Sharp Red grit after hollow-grinding with a hand-crank grinder. Because there is less material directly behind the edge, this type of edge is less durable (although the degree to this is more theoretical than in actual practice). the bevel of the skew should be flat, and this method does produce a hollow grind; the cutting edge and bevel are not parallel; Solution. This style is popular on tactical knives. The back of the chisels is a single hollow ground for which they come in less contact with the work area. Once I’m happy with the bevel, I finish up with an 8000 grit stone to polish the bevel. Here is the very first chisel I tested the hollow grinding on. This grind is also referred to as an ax grind. This grind is ideal for woodworking because you can follow the wood grain in relation to the bevel. All the edges are flat, and it's dishes in the center. Jim March KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider. Plane blades are honed using the hollow grind to register as described above, but we were told to hone chisels with a secondary bevel. 3,018. Sharpening a Hollow Ground Knife. However, rather than being concave, the edges taper along a rounded curve before meeting. The chisel bodies, accurately ground and hardened to Rc47-51, have polished outside faces and smoothly machined inner bevels. The latter will rock and you end up honing a rounded bevel. Can you offer advice? This effect is accomplished by starting the grind below the midpoint of the knife, creating a small wedge with concave sides that is extremely sharp and very easy to care for. Just one problem: I don't have a grinder. Curiously, when I lapped the back I found it had a perfect hollow in it! Also common on some military and "tactical" knives. Before you grind, you have to make sure that the back of the chisel is flat. -Cliff Nov 10, 2000 #13. Advertisement. I would have 50 chisels today but I ground quite a few to the stub over the years, same with plane blades. It doesn’t take long to grind a good edge on the inside of the chisel. Flat grinds are used mostly as kitchen knives and are not my favorite blade grind for a hunting knife. Hollow ground has the added advantage of naturally creating a stable "platform" so it's easier to hold the proper angle. This is done by rubbing the chisel along the stone with finger pressure constantly on top of the chisel, near the bevel (Figure 2). Its surface is concaved, and it starts cutting the target instantly. chisels not to grind. Traditional japanese chisels use a similar trick to hollow ground, but on the back of the chisel. Then proceed to demonstrate how to hone the hollow ground blade freehand on a … Mortising chisels should be flat ground, too, or made slightly convex, for the same reason. Hollow ground is similar, since you're only removing steel from small areas on the tip and back of the bevel. Sep 24, 2018 - Explore Neil Hicks's board "Hollow grind" on Pinterest. 2. The result was the ONEWAY Skew Grinding attachment. The face of the chisel (the hollow-ground side) should be lapped on a flat, medium-grit stone to ensure that it is flat. Add a micro bevel. I made a tool rest which I can run my finger along to guide the grinding and slide the gouge or chisel in or out to get the wheel in contact with the center of the bevel of the tool.