Hingst's Sign Post: Woodcarving Tool Care

By Jim Hingst

To prevent rust, periodically wipe your chisels, gouges and knives down with oil. Some carvers wrap their tools in rags. If you take care of your carving equipment, the tools should outlast you and several generations of your descendents.

Rather than keeping your tools loose in a box, store them in a container, which has separate compartments (one for each tool) that will prevent them from bouncing carelessly around and getting nicked. Other options for storing your chisels include a tool rack or a cloth tool roll.

When you are finished working, take the time to sharpen your gouges, so you are ready for work the next time that you need your tools.

Put it away where it belongs! How many times did you hear that when you were growing up? It’s good advice and will save you countless minutes searching for lost tools.

Stay Sharp.

Just as a musician needs to tune his guitar before a performance, you will need to sharpen your new collection of chisels and gouges before carving. Even if the tools look sharp, carving tools straight out of the box are not razor sharp. What’s more, in some cases, you may even need to reduce the angle of the bevel. Woodcarvers usually prefer the angle of the chisel to be between 15º and 20º. By comparison, your Stanley bench chisels typically have a 25º bevel.

Sharpening your tools to a shallower angle will give you a sharper blade. That’s the good news. The bad news is that, when the blade is sharpened at a shallower angle, the tip is weaker and will also dull faster. This is why many carvers will sharpen the blade with a slight secondary bevel.

And if you were expecting that the edge of your new carving tool to be perfectly sharp and ready to use, you will be disappointed. In most every case you will have to sharpen every new chisel and gouge.

If you didn’t buy sharpening supplies with your carving tools, put your chisels away, until you go shopping. Unfortunately, you won’t find what you need at your local Ace Hardware. For the specialized type of oilstones, slip stones and stops, you will have to order on line, or go to a specialty woodworking store, such as Woodcraft (www.woodcraft.com). If you buy quality natural sharpening stones, from a reputable source, they will last longer than you will, unless you drop them on the floor and break them.

A wide variety of sharpening stones are available on the market. One of the most common types is an oilstone. Some are synthetic, while others are natural stones. Of the natural types, the two best known are Arkansas stones and Washita stones.

Just as sandpaper is available in various grits, so are oilstones. At the very least, you need a coarse grit stone and a fine grit stone. A soft white Arkansas stone or Washita stone is comparatively coarse at 800 grit. A hard white Arkansas stone has a medium grit of about 1000.

You can tell whether the white Arkansas stones are the real thing, if they become translucent after you apply oil to them. A hard black Arkansas stone has a fine surface rated at about 1200 grit. Many carvers consider the natural stones as the best surfaces for sharpening, but they are also the most costly. (Note: Be careful in handling natural stones. If you drop them, they will break.)

As an alternative to the natural stones, synthetic stones are more affordable. Abrasives used in the manufacturing of these include silicon carbide, aluminum oxide and carborundum. An India stone is made with aluminum oxide abrasive. These synthetic stones are sold in fine, medium and coarse grades.

Sharpening stones are also available in different shapes. Bench stones are rectangular blocks, while slip stones are fashioned in configurations designed to match the various curves of gouges.

Waterstones and Diamond Stones

As an alternative to the traditional oilstones, many woodcarvers prefer using Japanese waterstones. Whereas oil stones use oil as a lubricant, waterstones use water. Whatever you do, don’t use oil on a waterstone or its surface will clog up with grit and it will lose its abrasive properties.

Waterstones gained popularity because they sharpen blades faster. That’s the good news. The downside is that because the stones are softer, they wear out over time. A high quality natural oilstone will stay flat and will outlast a lifetime.

In honing the blades of chisels, gouges and knives, Dr. Lestingi has tested a variety of stones including the natural and synthetic oilstones and water stones. After years of trying different products and techniques, he prefers using a diamond impregnated steel plate, called diamond stones.

Diamond stones are comprised of industrial grade diamonds adhered to the surface of a steel plate. These stones are available in a variety of grits. Although diamond stones are not cheap, the price is reasonable. Typical prices range between $30 and $35.

The primary advantage of a diamond stone is that it will rip through the metal in no time flat so you can sharpen your tools faster. Just as you should not use oil on waterstones, the same is true of these stones. Instead many carvers will lubricate the surface with a dishwashing detergent such as Joy. When are finished using the diamond, wash it off with water and dry it.

Not everyone is a big fan of these stones. Some feel that they abrade too much of the steel too fast. “If you have a nick in the blade or sharpening a brand new gouge, the diamond stones are great,” says Butch “Superfrog” Anton. “But in most cases, all you need to keep a blade sharp is to strop it regularly.”

Sharpening Technique

Learning to carve isn’t that hard. What is much more difficult to learn is how to sharpen your tools. Of course, your only other option is to pay for someone else to sharpen your tools for you.

Techniques and supplies for sharpening are as varied as carving techniques. Most of these sharpening techniques consist of some variation of a three-step process. In the initial whetting step the blade is sharpened on a coarse stone. This process is followed by honing on a finer stone. In the final sharpening step the blade is stropped on a piece of leather or a stropping board, until it is razor sharp.

Compared to sharpening gouges or v-parting tool, sharpening a straight chisel is relatively easily. First smear some oil on the surface of your stone (assuming that you are using an oilstone).

Although specialty oils for sharpening are available for use with oilstones, 3-in-1 oil is commonly used. While some people believe that the oil provides some lubrication for the sharpening process, its primary purpose is to float away any particles of metal, which are worn away from the blade of the chisel. Otherwise these residual particles would clog the pores of the stone reducing the abrasive properties of the stone.

Then hold one of the beveled edges of the blade flat against the sharpening stone with one of your fingers on the opposite side of the chisel’s edge. Most straight chisels used in woodcarving, have a double bevel blade.

The techniques for sharpening a gouge are different than that for a straight chisel. One technique involves turning the edge lengthwise against the stone to abrade the entire edge of the blade.

Dr. Lestingi says that one of the keys to sharpening chisels and gouges is to “lock your wrist”. What he means by this is to always maintain the same angle and pressure as you are sharpening. If you twist your wrist, you will not sharpen all parts of the edge the same. Keeping a consistent angle will ensure that the blade is square and that it is equally sharp along the entire edge.

As you are sharpening the blade, you should periodically inspect it to make sure that the outside corners have not become round. If the corners of the blade are rounded off, you can’t use the corners for cutting.

After sharpening your chisel with the coarse stone, repeat the procedure using a fine or hard stone. As I mentioned earlier, most woodcarving straight chisels are double-beveled. So you will need to sharpen both sides of the blade.

You should sharpen a tool until a fine burr or sliver of steel forms on the edge of the chisel or gouge. Until a burr forms, keep sharpening. The best way to determine if a burr has formed is to very lightly run your finger over the edge. If it feels rough, it’s time for step two.

To typical way to hone the burr off is to use a slip stone on the inside edge of the gouge. These sharpening stones come in different grades of coarseness.

Gouges have both an outside bevel and an inside bevel. If you want your gouge to cut properly, you must sharpen both sides. Not only does honing abrade the burr that forms, but sharpening the inside bevel produces a keenly sharp edge that allow you to turn the gouge over, giving you a second cutting edge. This second edge is essential for carving convex shapes, such as shells.

When you are done using your oilstone, you should wipe off and remaining oil and residual metal particles from the surface. Otherwise the residue will dry on the surface of the oilstone, clogging the pores and reducing the stones ability to act as an abrasive. Some carvers also clean the stone drenching its surface with a solvent, such as mineral spirits, and scrubbing it with a stiff bristle brush.

Stropping.

Burrs can also be removed by stropping the blade against a stopping board or leather belt, just as barbers would strop their razors before shaving someone. This is the final step in the sharpening process.

You can buy a leather strop, or one of your old belts will work too. Some people with glue a belt to a piece of wood with the rough side of the leather to the outside.

You will also need a stropping compound, which is available as a paste or liquid and is rubbed into the leather. To strop the blade, the edge is pulled from the furthest part on the leather to you. Do not rub the back and forth against the strop or you will cut into the leather.

“My father taught me that the most important step in sharpening is stropping the blade,” says Butch Anton. “For a stropping compound I use jeweler’s rouge. Regularly stropping the tool will keep its edge razor sharp so you won’t need to use your sharpening stone so much.”

Jewelers Rouge and other polishing compounds come in a variety of abrasive grade from coarse to fine. Just as if you were working with sandpaper, start with the coarse compound, then progress to a finer grit. Continue polishing the blade of your tool until it has a mirror finish.

Another good habit to form is to always sharpen your chisels and gouges, before you put them away at the end of the day. That way, your tools are ready for carving.

If you are confused about how to sharpen you tools, I recommend that you find someone to teach you or buy an instructional video. Several excellent DVDs on sharpening are available from master woodcarvers, such as Chris Pye and Nora Hall.

About Jim Hingst: After fourteen years as Business Development Manager at RTape, Jim Hingst retired. He was involved in many facets of the company’s business, including marketing, sales, product development and technical service.

Hingst began his career 42 years ago in the graphic arts field creating and producing advertising and promotional materials for a large test equipment manufacturer. Working for offset printers, large format screen printers, vinyl film manufacturers, and application tape companies, his experience included estimating, production planning, purchasing and production art, as well as sales and marketing. In his capacity as a salesman, Hingst was recognized with numerous sales achievement awards.

Drawing on his experience in production and as graphics installation subcontractor, Hingst provided the industry with practical advice, publishing more than 150 articles for publications, such as Signs Canada, SignCraft, Signs of the Times, Screen Printing, Sign and Digital Graphics and Sign Builder Illustrated. He also posted more than 325 stories on his blog (hingstssignpost.blogspot.com). In 2007 Hingst’s book, Vinyl Sign Techniques, was published.

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Tuesday, September 16, 2014

Woodcarving Tool Care

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