September 2011 Edition
Focus on Wood - Mulberry
Mulberry is a close relative of the more commonly known osage orange tree. Mulberry trees are relatively uncommon in most areas of the US, but can grow to sizes of well beyond 6' in diameter in some cases. The wood is somewhat aromatic, and is an excellent choice for turners both amateur and professional alike.
Mulberry, red mulberry, moral
Medium to bright yellowish-brown or yellow color with bright white sapwood.
59 lbs/ft3 - Similar to most hard maples and hickories
1250 lbft - Similar to red and white oak
Turns very well. Mulberry has a moderately fine grain. Cuts easily when green, despite its hardness. Only slightly more difficult to turn once dry, but with very little dulling effect on tools. Very little tendency to tear out when cutting across end grain.
Dries well, with only a slight tendency to warp, twist or check. Drying should be given slightly more time than other woods, as this wood releases water more slowly.
Sands very well. For removing tool marks, 120 grit sandpaper is recommended. Will sand to a very high luster, usually requiring grits no higher than 600 to achieve satisfactory results.
Readily accepts most stains and finishes without need for any special pre-treatment of the wood surface. This wood will fade to an orange-brown color with age. To ensure that your turnings stay the much brighter, more vivid yellow color, a hard finish such as lacquer, shellac or polyurethane are recommended instead of oil and/or wax finishes.
There are no known toxicities associated with mulberry.
Turning Tutorials - Reducing Lathe Vibration, Part 1 of 2
Reducing Lathe Vibration, Part 1 - Improper Technique
Most of us, especially those with smaller lathes, have experienced the frustrations caused by vibrations when turning with our wood lathes. There are a wide variety of factors that can cause vibration...here are some tips for reducing the problem. In this first part of our two part series about lathe vibration, we're going to cover problems that are caused by the turner...not the lathe itself.
Improper tool sharpening -
Dull and improperly sharpened tools require more force to be placed on the tool to cut the wood. Using additional force against the wood can cause the piece to vibrate. These vibrations show up as "chatter" marks on the wood's surface. Keep tools properly sharpened at all times!
Excessive force used in cutting -
As a turner, you must learn to let the tool do the cutting for you. While it may be tempting to push one's tool into the wood as quickly as possible, this is not the proper way to turn. As with improperly sharpened tools, the additional force that is placed on a piece will cause vibrations which lead to chatter marks. Using a light touch with enough pressure to keep the tool moving in the proper direction will greatly reduce chatter marks caused by the vibrations that are no longer being created.
Improper cutting direction -
A few months ago we covered proper cutting direction in our newsletter (see our archive for these back issues). Cutting wood in a manner that causes the fibers of the wood to be torn, rather than cut, can cause issues with vibration. As wood fibers are torn away from one another, the wood tends to vibrate slightly, producing a slightly uneven surface. In addition to this, the torn wood fibers create a rough, fuzzy looking surface. This rough surface will cause additional vibrations as well, as the tool will lightly bounce across the rough surface on occasion. If you aren't confident with how to properly cut your wood, I highly suggest looking over our tutorials mentioned above.
Improper mounting of turning stock -
While this may seem self-explanatory, we wanted to touch on two important issues concerning proper mounting. For side grain projects, such as bowls and platters, keeping things as well centered when mounting will, of course, reduce vibration. For spindle projects, proper centering is also important, but the amount of force placed on the wood between the headstock and tailstock also come into play. This is especially noticeable in longer and/or thinner projects. Excessive force coming in from the ends of the wood can actually cause the wood to flex along its length. Use just enough force to keep your wood in place, but not enough to cause the wood to flex.
In next month's issue, we'll explain what problems can be caused by the lathe, and cover the remedies for each of these situations.
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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