Deciding which way to stack the layers that make up the
main feature rings is next. There are
two different ways as shown in the two photos below. For me my eye travels from right to left
across the layers and having the hard vertical edge of the cherry on the right
as in the bottom looks better. I think
it makes the layers look stair stepped versus a ramp like in the top
photo. Others may have differing
opinions.
This bowl will have two individually turned halves. The bottom section is up through the main
feature rings and the top section is down to the top main feature ring. Once shaped inside and out the two halves get
glued together then the final detailing is done. What that means is with most of the rings
made and ready to glue to the bottom half I will start working on the top
half. The top starts by using a second
face plate along with a mounting block just like the bottom half. Here that’s been done along with the bowl's very top
layer glued on turned round and the face squared to the lathe’s main axis.
Adding the second layer to the bottom half feature ring
is next. Normally the joints in the
layers are staggered by half. However,
with the four feature layers they are staggered by thirds. That requires marking the first layer as
shown below. When I glue on the second
layer it goes on the right pencil line, the third on the next line to the left
and the fourth layer lined up with the existing layer’s joint.
There are three regular layers at the top half before getting
to the feature layer there so right now in progress are the main feature rings being
glued and turned round on the bottom half.
At the same time the top half ring’s segments are being cut, glued into
rings then flattened with the thickness sander and glued on. This is what all that looks like. At the far right is the bottom half with the
second feature layer glued on.
While the three glued up pieces are curing it’s back to
working on the top half’s feature layer.
The blank I made earlier is thicker than needed so I will use the
bandsaw to bring it down close. Here is
the bandsaw setup from the outfeed side.
After bandsawing and running the piece through the
thickness sander the blank gets squared up and ripped into four strips. Each of these strips when cut give four
segments.
Next is to start cutting the segments which is a
multistep process that requires a fair amount of measuring plus some trial and
error to get the exact sizes needed. The
top photo shows the first cut which is set using a stop block on the left. Here the critical dimension is the distance
between the right edge of the maple strip and the right cut edge. Once that’s set the right end's stop block is set and a
scrap used to check the size. When it
gets really close, I use a playing card to move the stop one-hundredth of an
inch at a time as shown in the bottom photo.
The inset shows the end result being just .0005” over and that’s plenty
good.
With that stop in place the first segment is flipped top
to bottom and cut. That’s followed by cutting the same end segment from each of the other three strips.
Cutting a segment from the other end is next. It follows a similar process except the
reference end up against the left stop is not square so an angled piece is
used. The top photo shows that setup and
the waste cutoff. Using the already set
stop on the right the segment is cut to final length leaving only the center
section to be cut.
Here is what the four strips look like with the end two
segments cut to size leaving just the center four to be sized.
These last four follow the same process albeit with the
left stop set at a different spot as shown in the top photo. The bottom photo shows the piece flipped over
and cut using the same right stop as the rest of the segments. A side note; when I cut these small pieces I
used the eraser end of a pencil to hold them in place and not my fingers.
Once the segments are cut, they follow the same assembly
procedure as the other rings. Here the
ring has been glued to the top stack, turned round and the next layer glued
on. This last ring presented a little
problem because the previous layer did not have a large enough “step” for the
clamps to get good support. The fix is
to use some spacers (red arrows) the same thickness as the layer, in this case
leftover cutoffs from the feature layer segments. There are still four more rings to add to the
stack, so a bit to go.
While I was working on above the top feature ring the
four main feature rings got glued on and turned round. This completes the stacking of rings on the
bottom half and this is what that looks like.
Next is to knock off all the corners, get rid of the
steps turning both the outside and inside down to a rough shape. This makes it look a lot more like a bowl
versus something made out of LEGO® blocks.
There is still a long way to go but this will give you an idea of how
the turning progresses.
Earlier in this project in the seventh posting Assembling
the Base Parts & Adding Layers I showed one way to help keep the new rings
from sliding around by using some Quick-Release Ratcheting Hand Clamps. They work OK but can slip a bit when the
other clamps are tightened. A more
secure way is to use “F” clamps that have a much greater clamping force and are
much more resistant to being pushed out of place. The photo shows one in place. The only thing to remember is to remove them
after about 10 minutes. That keeps them
from being glued in place or in this case staining the oak if the glue reacts
with the oak and steel of the clamp.
Next Up – Refine Bowl’s Shape, Cutting Top Free & Finishing Top Lip
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