Shaping the profile at both ends of the leveling bar is
next. Below the top drawing shows the
profile as originally planned. The
bottom shows how that was revised to eliminate the 90 degree interior corner by rounding
it off. That’s done because an interior
corner is a good place for a crack to start when the member is loaded in use. An arc reduces the concentration of forces
spreading it out across the arc.
After making a template out of scrap its profile is
transferred to the actual leveling bar.
Since there are 12 ends to be done, I put together this simple jig to
hold the pieces in alignment. From here
all that's required is a simple tracing of the pattern’s profile.
The shaping begins with drilling a hole close to the
final size of the corner arc. Rather
than try and measure out where the center point of the arc is I just took the
drill bit and eyeballed about where it goes making sure to leave a little
material to be removed later on when the curves are all blended together. The left photo shows the drill press setup
with stops set for consistency in drilling and the right is a little closer
look.
Using the table saw to cut the left vertical edge is
next. The top photo is of the table saw
setup with the stop on the right clamped to the backer board to set the cut’s
location. The bottom photo is a close
view with the finished cut.
Next, it’s over to the bandsaw to cut the curved face.
Refining the bandsaw cut into a smooth set of curves is
done on the oscillating drum sander. The
first pass is with a coarse grit sleeve and the second with a fine grit sleeve
for a smoother surface. From there some
hand sanding with a yet finer grit finishes the transitions between the curves
giving the final smooth surface.
The leveling bar parts are complete except for some final
sanding and the application of some self-sticking sand paper.
The next part is the leveling wheels. They will be used to adjust the leveling bars
which will provide solid support for the wood planks to be flattened as they
are run thought the planer. The drawing
below shows how the wheels fit into the leveling assembly.
There is a dozen of the wheels needed and in the original
plans they were made out of ½” plywood.
I really do not want to use plywood because, I don’t like the feel of
it or the tendency of its softwood layers to splinter. However, in this case because of the
cross-grain structure of plywood it will be less likely to split versus a solid
piece of wood. My solution is to make my
own plywood out of oak. It’s going to be
a little time intensive but worth it.
Since I need to make 12 leveling wheels and each wheel has 5 layers
that’s 60 individual pieces. As it
happens in my stack of scraps there are several leftover rips less than 3/16”
thick that can be used. The problem with
them is they cupped pretty badly after being cut that thin as can be seen in
the photo below.
The problem is mitigated by ripping the 4” wide boards in
half on the table saw. This works out
well as the final wheel diameter is 1 5/8”.
There is only one consideration when making the rip and that is to have
the cupped edges up like in the top photo.
If the cut was made with the cup down then when the rip is done the
pieces will fall down onto the saw’s top possibly getting pinched against the
blade causing a kickback shooting the piece right at me. Believe me that’s something to be
avoided. The bottom photo shows how much
less cup there is to take care of after the piece has been cut in half.
Thickness sanding to flatten the piece and bring it to
the final 1/10” thickness is next. That
starts by placing the crown of the cup up and marking it with a pencil. The top photo has that done and is ready to
be run through the thickness sander.
After a couple of passes most of the crown is gone as shown in the
bottom photo. A couple more passes and
the opposite side will get the same treatment to flatten it also.
Once flat the pieces continue to get run through the
sander gradually reducing the thickness to the required 1/10”. The top photo shows the completed edge and
face. Cutting to length is next which is
done on the chop saw with a stop block.
The bottom photo shows most but not all the stacks of pieces needed.
Because there are a dozen wheels, I worked on a couple of
simple jigs to make the gluing process go faster and easier. The top photo is of the main jig empty and
the bottom one is the first of two batches of wheel blanks glued up.
Stepping back to go through the process here are the
blocks used to hold the small individual layers in place while the glue is
spread on them. Note how the grain in
each layer runs 90 degrees to the adjacent layer. The bottom is a closer look after the glue
has been applied.
With the glue applied the five layers are stacked up
to make a sandwich. The stack is moved
to the clamping jig as show here. To
keep the piece from getting glued to the clamping surfaces the base is covered
with a 6-mil piece of polyethene film and the back stop is covered with clear
packing tape.
Next in the top photo a clamping block also covered with
packing tape is clamped to hold the glued layers in place. That’s followed by a caul on top of the stack
to spread the clamping pressure evenly across it.
Next Up – Completing Wheels & Sliding Blocks – Base Plate, Sliding Blocks Test Assembly
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