This vase was a very interesting
project, so much so that I have done others that employ a similar
technique.
Start with four billets of ash (or
a wood of your choice) of square cross-section. I try to make
the proportions so that my finished project will conform to the
golden section. (The ratio of the Width divided by the Length
equals approximately 0.6.)
Lay up the four billets so the portion
of each that will form the interior of the vase is now on the
outside corners of the composite block. I stick these together
with double sided tape and wrap several turns of fiberglass reinforced
packing tape around the outside where I will not be cutting. If
I eventually need to cut in those areas where I have taped, I
put more tape in an area where I have already turned.
I put this taped-up block between
the centers of my lathe and turn at a relatively slow speed. Before
turning on your lathe, check for clearance of the tool rest. I
have turned vases of this sort where I needed to use a hand saw
to cut a V-shaped notch in the block to clear the banjo of the
tool rest.
Cut the contour of the inside curve
of your vase. (Take care that you stay clear of those rotating
corners. They can hurt!) You can check your progress by multiplying
your depth of cut into the block by two and that will be the width
of the space inside your vase when it is finished. You do not
want to turn down so far as to round off the flat surfaces of
your block. I have found that if I do this I have cut too deep
to allow me to achieve the contour I want on the exterior.
You can turn the block so that you
have a smooth cut to form the interior, or you can leave it rough.
I have turned vases where I cut the interior so that it looked
like it was hand carved. This creates a real puzzle when one realizes
that there is no opening large enough to admit a carving chisel
or gouge! This is the time to do any sanding or finishing you
want on the cut portion of the block. If you apply finish, be
careful not to put it on the flat portions of your billets. These
surfaces form the glue joints when you glue up your vase.
When you are satisfied with the internal
contour, remove the block from the lathe. I number the billets
at this point so I can preserve the sequence of their arrangement.
Pull your composite block apart, turn the billets so the "outside"
corners now form the outside, and glue them up. You should have
a block that looks solid, revealing nothing of your previous cutting.
When you start turning the outside,
you will soon open up "windows" to the inside of your vase as
your cuts now intersect with the previously turned interior contours.
These windows can be dangerous so keep your fingers well away
during all operations. As these windows open, you get a view of
the interior shape and can easily follow with the outside contour.
Leave the vase oversized at this point so that later you can make
the various curves flow together.
I cut a flat in the place of the
cove above the bun foot that is wide enough for my steady rest.
I leave a shoulder on the topside of the cut for the steady rest
to ride against. Orientate the block so the top of the vase is
against the drive center in the headstock and the base is supported
by the live center. I now attach my steady rest so that it is
supporting the vase just above where the bun foot will be and
so that it is pushing the vase snugly against the drive center.
Pull the tailstock away, turn the lathe on (slow speed), and shape
the bun foot.
I use a similar technique to shape
the neck and lips of the top of the vase. Orient the vase with
the bun foot against the drive center. I cut a flat in the area
that will form the neck of the vase and leave a shoulder that
will allow the steady rest to hold the foot firmly against the
drive center. With the top held in place with the live center
in the tail stock, position the steady rest in this flat.
Using a drill chuck in my tailstock,
I drill an appropriate sized hole through the neck to the interior
of the vase. Then I shape the lips and bring the interior curve
of the lips to flow into the hole I drilled.
Put a cone center into the tailstock,
push it up to the top of the vase, and remove the steady rest.
Now I make my final cuts so that all the curves flow together
and cut the cove above the foot. I elected to score and burn a
couple of lines on either side of the cove. I have had people
comment that they really liked the effect of the "walnut inlays"
above and below the cove!
If the edges formed by the interior
contours meeting the exterior have chipped while cutting the exterior,
you will need to dress them with sand paper or a small file. I
finished my vase with a buffed wax finish that gives it a nice,
soft luster.
Good luck on your project!
Ellis Hein
ebhein@coffey.com
websites.celltech.com/healthhelps/turnings.htm