Tips
on Sharpening... Sent by Mack Cloninger
Tips
on Sharpening... Sent by Mack Cloninger
Editors Note: MacK Cloninger is an origional forunding member of the Aiken Wood Carvers Club whose job took him to Colorado a little over a year ago. Mack is an exceptional wood carver who pay great attention to the minute detail in his work. - Jack
First of all, I must state, I am not an expert on sharpening tools. There are books that cover sharpening only and I encourage you all to read at least one. The reason for sharp tools cannot be emphasized enough. THE MOST IMPORTANT ingredient for success in carving is having sharp tools. Carving with dull tools can be a frustrating experience, to say the least. Ajudge will spot a carving done with dull tools in a minute. I can recall one of my first classes with a professional carver: He asked us all if we were satisfied with our tools and sure of their sharpness before we were to commence the class. I thought my tools were the sharpest tools known to man and was ready to prove it. Boy! Did I get a rude awakening. When my instructor showed me how to sharpen and sharpened a few of my "good" ones, the difference in cutting wood was phenomenal. I could hear the blade sing as it cut! There's the key! Listen to you tools. They will, I guarantee, tell when they are sharp as well as when they are dull. So, with all that said, we will proceed with MY method of keeping sharp tools. You will develop your own as you grow in the art form. There are, basically, three steps to sharp tools: 1. Whetting , 2. Honing, and 3. Stropping. The ONLY time we "grind" is when we have broken a tool or need to reshape one we have. Be careful when you grind not to ruin the blade with too much generated heat. Water never hurt a tool, but too much heat (from grinding) will do it quick. Whetting is generally done with a "Washita" type stone (a yellow or gray natural stone). Honing is usually done on a "Arkansas" stone (usually the white one). Stropping is done on a "strop stick" or a powered stop of some kind. For gouges, you will also need a set of "slip" stones (usually Arkansas or ceramic) to get to the inside. For my own sharpening, I have the following: Grinder, powered strop, strop stick, buffing wheel, leather slips, and diamond honing stone. My grinder is a standard bench grinder with "medium" on one end and "fine" on the other. I don't use it very much, because I am not very good at holding a blade level when I am thinning or shaping. I use a home-made unit that consists of a 5" piece of circular _" plywood with "stick-on" sanding discs (fine) and a º" mandrel. I have discs cemented on both sides so I can do both sides of the blade with the sanding surface turning away from the blade edge. If you have a reversing drill motor or drill press, you need a sanding surface only on one side (reverse the motor to do the other side). This system allows me to hold the whole blade at a shallow angle and shape the entire blade at one time. Be careful! You still have to be aware of the heat generated so as not to burn your blade. Once I have shaped the blade the way I want (or gouge), I can then hone. I use a diamond hone mounted on a piece of wood (about _" thick) with a handle on one end. I use a "fine" hone. The size of the diamond hone is 2" x 6". With this diamond hone you can take off a lot of metal, and you will have a hard time wearing it out (Harold Enlow told me he has worn one out, but I haven't, in fact, it cuts better the older it gets). As an aside: The hone will remain essentially flat and you use no lubricant. To clean it, you just wash it off. When the blade is honed, I will then go to my power strop if I home, if not then to the leather stick strop. My power hone is, again, a home-made unit. It's a piece of _" (circular), 6" in diameter, plywood with leather glued on both sides (leather is inside out) mounted on a mandrel run from an old washing machine motor. I use a belt and pulley system to drive it. The motor turns at about 1700 RPM and the small-to-large pulley arrangement drops this to about 600 RPM. I use the power strop to remove the "wire-edge" and polish the blade. I use "ZAM" (3" stick) as a buffing compound. If I'm sharpening a gouge or V tool, I use one of my leather slips (2" x 4" with edges formed to fit inside a V tool or gouge) that I have "charged" with ZAM. Works for me! If I'm at my bench carving, every so often I will stop and strop on my "strop stick". My strop stick is a piece of leather 21/4" wide and 7" long glued to a piece of wood with hand holds on each end. The leather is glued with wrong side out. I tried it with the smooth side out, but I found it would not hold the ZAM without a binder of some kind (oil, water, detergent, etc.,). With the rough side out, it holds the compound very well. When you are done sharpening your tool, give it a test. There are a couple of ways you can do this: 1. Drag the blade along your thumb nail (as though you were going to cut a very thin slice off it). If it catches, it is sharp. If it glides across the nail, it is not. 2. Cut across the end grain of a piece of wood. If your cut is smooth and shiny, it's ready. If the cut is dull and white looking, its back to the drawing board. My technique for honing a blade, gouge, and/or V tool, is pretty much the same for all. I try to cut a very thin slice off the surface of my diamond hone as I push my tool along its length. For a gouge, I am slowly rotating as I push. For the V tool, I do one side and then the next as I watch the bottom of the V so as not to form a "hook" or "cut" in the bottom of the V. Try to keep the edges in line with each other as you hone. As you hone the tool, bounce the cutting edge into a piece of wood to break off the burrs. This allows you to better see the cutting edges as you hone. The "V" tool is the hardest tool to sharpen next to the Marconi. My first V tool was 5" long when I started and 3" long when I finished. I do not do any honing with power. I do it all by hand. It takes a little longer to hone this way, but the diamond hone makes the job easy. By the way, if you buy a diamond hone; make sure it's the one without holes in it. The one with holes in it does not lend itself well to sharpening small tools. When you use the leather slips, you charge them with the buffing compound the same as you do on the leather strop. Pull the tool towards you to smooth the inside as desired. When all of your tools are sharp, all you need do is to touch them up on your leather strop. You'll only have to go to the power strop or diamond hone when the cutting edge starts to round over. Finally, find a good place to store your tools and protect them. I have two tool boxes, one for everyday and one if I want to show off. All of my blades on my gouges are covered with plastic tubing. All my bench knives have leather covers. My pocket knives are in a separate box with a small, slightly oiled cloth. My everyday tool box is a fishing tackle box, my once in awhile box is a large carpenters box (plastic, Sears). I also have a travel tool box that is an old wooden pencil box with a leather handle on it that I bought at a flea market. Tip of the Day - If you cut relatively soft woods (bass, pine), make the angle of the cutting edge about 15 degrees and long. If you are cutting predominantly hard woods then make the angle 20 to 25 degrees. Your tools will cut better. Keep Those Chips Flying! Willis (Bill) Sharp bsharp@gvn.net
A "STROPPING" Fine Finish: Strops provide more fine tuning than most veterinarians are wanting for their necropsy knives. But if you are interested in a little strop trivia, read on. As mentioned earlier, a pinch of Silicon Carbide, Aluminum Oxide or a dry buffing compound works great as a loose dressing for strops.
When using a strop never let the blade "bite" into the leather. Biting occurs when the back of the blade is lifted too high and the cutting edge of the blade scrapes along the strop. Keep the blade almost flat against the strop. As the edge passes the soft surface of the strop will curl up against the edge producing a convex edge. If you allow the edge to bite the strop the strop surface will actually curl up over the edge and cause dulling of the cutting edge. It is easier to use a strop if it is attached to a rigid surface. I glue thick l eather (10 to 12 oz), slick side up, to a piece of wood. A thick woven cotton strap also works well, but holds more abrasive compound and does not produce the fine edge produced by heavy leather.
Strop leather should be oiled before used the first time, there after no more oil is needed. Strops should be at least two inches wide and twice the length of the knife blade you need to work. I mentioned cleaning abrasives with water ... DO NOT CLEAN A STROP WITH WATER. Testing the Edge: Shaving your arm is impressive. The preferred way is to rest the blades cutting edge (at a 45 degree angle) on something smooth, like your finger nail or BIC pen. If the knife does not slip down the smooth surface, it is sharp.
Sharp blades should be smooth. Smoothness can be tested by lightly sliding your finger nail or a BIC pen across and down the blade. A perfect edge will not reflect light (candle). Look for reflections from the edge.
Final Note: There is an old saying about a "dull" knife being more dangerous than a "sharp" knife. I'm not sure that is true, but a dull knife often does require more force to be applied to the cutting surface. Slips under pressure are hard to control, therefore could be more dangerous. It is important to control the direction of the cut, and to use a slicing motion (not a straight push or pull against the blade). For safety consider using a "cut resistant" glove. You can get one from your knife supplier. They only cost about $12 per glove. They are not stab proof, only cut resistant. The most common injury is the "stubbing" injury which happens when the knife hand slides from the handle onto the blade. A "cut resistant" glove will help protect you against this injury.
