20
As there are dozens of chucks to choose from, the
woodturner should first consider all the different
types of turning that will be done, and read reports
or discuss with other turners who own chucks
before making a decision.
A chuck is not a requirement, but is handy when
working on more than one piece at a time. Rather
than removing screws, you simply open the chuck
and change workpieces.
The most popular ones are four jaw scroll chucks
with a variety of jaws to accommodate different
size tenons. Most also come with a screw chuck as
well.
9.6.3
Wood 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.
9.6.4
Checks 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.
9.6.5
Distortion
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.
9.6.6
Tools 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.
9.7
Bowl Turning Techniques
9.7.1
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 9-10. 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 9.6.1
"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.
