I saw this piece made during a lathe turning
demonstration. It is made from a single
piece of wood and I wondered if I had the skills to do it so decided to give it
a try. Here is a drawing of what I am
going to try and make.
It all starts with a single piece of wood. I had this piece of red oak in my leftovers
box which you can just see in the lower right of the photo. It is a little over 6” square and about 7/8”
thick. Unfortunately, it was warped and
not of much use which is why it was in the leftover box. Using the hand plane, I worked this face flat
then ran it though the thickness sander to flatten the other side. Probably too much work just to get a flat
board but I just hate to waste wood.
With a nice flat board I could start on the layout. Below is the drawing I used. First, I drew in diagonals to get the center
point of the square blank then offset my ring center a ¼” off on the diagonal. Using this as a starting point I drew in the
concentric rings for reference.
With the layout done I pulled out my face plate and MDF
mounting board. This is the mounting
board I used when I made the Snare Drum.
After I screwed the face plate onto the lathe I set the
live center in the tailstock right at the center of the blank and advanced it
to hold the board tight to the MDF mounting board. The two screws at the top and bottom of the
oak blank were then screwed in. Here
everything is set ready for the screws to be run in.
Here I am ready to start dishing out the mounted blank.
The idea is to turn a nice radiused edge into a flat
bottom dished out area. This is what it
looks like after doing some turning where I am pretty close to being done.
I want the bottom the dished-out area to be 3/16”
deep. In the photo you can see that the
caliper shows I am a little over 1/8” deep.
To use the caliper this way I set the right jaw on the top of the 6”
ruler then run the left jaw out until the outside face is flush with the bottom
of the ruler. The dial is then set to
zero. Now as the left jaw moves into the
dished-out area it gives me the distance from the edge of the ruler which is
setting on the face of the blank to the bottom of the recess. No math required which means one less place
for an error to occur.
When I get to the right depth the bottom of the turned
area is pretty flat but it still has some ridges and unevenness. To get a really flat bottom I take a small
block of wood to guide a piece of sand paper to even and flatten the bottom. The last step here is using a pencil to mark
the center of the dished-out area.
Next is to unscrew and remove the blank from the MDF
mounting plate and redraw the offset concentric circles like I had done
earlier. OK, you ask why did I draw them
on in the first place if they were going to be removed when dishing out the
blank and I was going to have to redraw them in again. It’s because I was not really sure exactly
what I was doing and wanted to lay the whole thing out to help me get clear
what I had to do. If I had done a bunch
of these and had the process down pat there would be no reason to do that. Also, these lines are not the actual guides
that I will use to make the cuts. That
will be done with a set of dividers making scored circles in the blank. More on the how and why when I get
there.
Now its back to the lathe using the live center in the
tailstock to center the blank on the offset concentric circles. In the photo you can see the original center
of the blank just ¼” above where the live center is now.
The mounting screws in the oak blank can now be run into
the MDF mounting plate. One note since
the blank is off center the screws do not go back into the same mounting holes.
Next Up – Overlapping Circles Completing Turning &
Finishing
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