May 2014 Edition
Focus on Wood - Butternut
Butternut is very similar in appearance to black walnut, but is a much lighter golden brown color. The heartwood varies between light reddish brown to golden brown, and the sapwood is white to off white in color. This wood is becoming increasingly scarce, as many trees are being attacked by insects throughout their native ranges.
Butternut, white walnut
28 lb/ft3 - Medium density
490 lbft - Moderately soft
This wood turns quite well. Being of a medium density, it has a slight tendency to tear out when cutting across end grain areas.
Dries very well, with minimal warpage, and little tendency to check or crack during drying. May require extended drying times due to a moderately high initial moisture content.
Sands very well. For removing tool marks, 120 grit sandpaper is recommended. Will sand to a very nice high luster, usually requiring grits no higher than 600 to achieve excellent results.
Readily accepts most finishes and stains. Stains may produce very different colors on heartwood areas when compared to sapwood areas.
No known toxicities exist for this wood.
Turning Tutorials - Turning with Sharp Tools - Radiused Skews
Turning with Sharp Tools - Radiused Skews
Last month, we continued our series of tutorials which are covering the proper sharpening of lathe tools. In the introduction tutorial in that newsletter, we covered the proper ways of identifying dull lathe tools. This month, we're going to explain the proper method for sharpening radiused skews. Next month, we will cover parting tools.
When to Sharpen -
Radiused skews should be sharpened as soon as they begin to produce dust, rather than smooth ribbons of wood while cutting.
Correct Sharpening Angles -
There are two angles which must be maintained on the radiused skew. The first angle is measured across the widest face of the tool, from side to side. The most common angle used here is approximately 20 degrees, as shown in the photo on the left below. The length of the bevel should be one and a half times the thickness of the skew, as shown in the photo at right below. For example: if your skew is 1/2" thick, then the length of your bevel should be approximately 3/4" long.
Grinding Methods for Skews -
Radiused skews can be ground in a number of ways. Let's look at the most common sharpening methods, and how each method can affect the tool's performance.
- Sharpening with a Grinding Wheel
Grinding wheels will produce a slightly concave (hollow ground) surface on each side of a skew, due to the rounded shape of the grinding stone. This concave surface causes two potential problems: the turner may have a more difficult time maintaining contact between the bevel of the tool and the wood being turned, and the cutting point can become dulled more quickly. It is highly recommended that a skew that is sharpened on the grinding wheel be honed afterwards to produce a more flattened surface along the bevel. This can be accomplished with a belt sander, or by using a hand held file, as detailed below.
- Sharpening with a Belt Sander
A belt sander is an excellent alternative to using a grinding wheel for sharpening the skew. A belt sander produces a flat ground surface on each side of the skew, which is ideal when using this tool. The flattened bevel allows the user to more easily keep the tool's bevel in contact with the wood while turning, and will allow the tool to maintain a sharper edge for a longer period of time between sharpenings. Be sure to maintain contact with the cutting edge and heel of the bevel against the sanding belt at all times, and keep the front edge of the skew perpendicular to the direction of travel of the belt to maintain the correct angle between the long point and short point of the tool.
- Hand Sharpening
Most turners prefer to hand sharpen their skews unless they are incorrectly sharpened, or have become damaged (nicked or blunted from using the tool for scraping cuts). Incorrectly sharpened or damaged tools will require more aggressive reshaping, and should be done with a grinder or belt sander. A small diamond file or sharpening stone can be used for this process. Simply maintain contact with the point and heel of the bevel against the stone, and make several light passes on each side. This is typically all that is required to maintain a very sharp edge on a skew.
All archived monthly newsletters do not include the following:
- Business updates
- Recently added woods and schedule of upcoming woods
- Photo of the month contest results
- Discounts and upcoming sales information
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