10.6.3Wood Selection
Firewood is the cheapest, most widely available stock to use while learning to turn bowls. Simply waste wood for a while practicing turning techniques. Develop skill with each tool before attempting to make a finished piece. It is best to start with dry wood, without worrying about drying or distortion. Once turning becomes comfortable, try green wood which cuts very easily. As the turner gains experience, he or she will find extraordinary grain and figure in the form of burls, crotches and bark inclusions.
10.6.4Checks and Cracks
Green wood will check and crack. For best results, leave logs in as long a length as you can handle. As the material starts to dry, surface cracks will develop on the ends of the log. Cut off two to three inches and you should find good, sound wood. Also cut the log in half along the pith to avoid having it in the finished piece. Most checks radiate from the pith.
As you turn bowls from green wood, make sure you maintain a consistent wall thickness throughout the piece. Leaving a piece thick in some areas and thin in others will cause the wood to dry unevenly and promote checks and cracks.
10.6.5Distortion
Distortion is a problem associated with turning green wood. It will vary from one type of wood to the next. Typically, fruitwoods tend to distort more than others. It also varies with the time of year the tree was cut and how the logs are stored.
10.6.6Tools for Bowl Turning
The deep fluted bowl gouge is the most essential and versatile tool for most bowl and plate turning. The bowl gouge is heavier and easier to control than other types of gouges. It also allows removal of wood much faster and with less vibration than other gouges. Most average sized bowl work can be accomplished with a 3/8" or 1/2" bowl gouge.
A 1/4" bowl gouge is best suited for smaller bowls and light finishing cuts. Larger 3/4" and 1" bowl gouges are only used for extremely large pieces.
Large domed scrapers can also be used to help clean up the interior surfaces of bowls. A light touch with the scraper slightly tilted will eliminate some of the ridges occasionally left by an inexperienced bowl gouge.
10.7Bowl Turning Techniques
10.7.1 To Shape Outside of Bowl
1.Odd shaped burls, crotches and other irregular shaped blanks require special preparation before mounting in a chuck or onto a faceplate. Remove the bark, if there is any,
from what appears to be the center of the top of the workpiece.
2.Drive spur center into the top of the workpiece with a mallet or dead blow hammer.
3.Slip the spur center into the headstock taper and bring the tailstock with a live or ball bearing center into position. Lock the tailstock to the bed and advance the tailstock spindle in order to seat the cup center into the workpiece. Tighten the ram locking handle.
4.Turn workpiece by hand to ensure proper clearance.
5.Start lathe at lowest speed and bring it up to the maximum safe speed for the size of work to be turned. If the machine starts to vibrate, lower the speed until vibration stops.
6.Rough out the outside of the bowl with the 1/2" deep fluted bowl gouge, holding the handle of the tool firmly against your hip. For best control, use your whole body to move the gouge through the workpiece.
7.As the bowl takes shape, work on the bottom (tailstock end) to accommodate attaching a face plate.
8.Turn a short tenon (about 1/8" long) the size of the hole in the faceplate. See Figure 30. This will allow centering the workpiece when the faceplate is attached.
(NOTE: If you plan to use a chuck, turn a tenon of the appropriate length and diameter to fit your chuck.)
9.Stop the lathe, remove workpiece and attach face plate or chuck (see section 10.6.1 "Mounting Stock").
The surfaces of faceplate and workpiece should mount flush to each other.
10.Finish turning the outside of bowl with 1/2" or 3/8" bowl gouge. Leave additional material at base of bowl for support while turning interior. This will be removed later.
Figure 30
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