by Yun-Han Lin
A sneak peek of the procedure first!
Some Makers from the woodworking classes shared with us some leftover pieces of tropical hardwood that came in different types and colors. As we happened to be practicing using a lathe, we might as well make a salad bowl with the pieces.
We decided to build the bowl with three layers- A, B, and C. Layer A was the octagon on the top, layer B the octagon in the middle, and layer C the hexagon at the bottom. The three layers were assembled separately and then stacked up together to form a pyramid.
We mixed up the wood pieces for the three layers, trying to get different kinds of wood evenly distributed. Next, we drew the cutting line based on the design sketches, where layer A was made up of bigger trapezoids, B with smaller ones, and C with regular triangles.
Bevel cutting with a circular saw
The bevel cutting this time was done through tilting the saw blade. Usually, the saw blade needs to be raised rather high when making a bevel cut, so be extra careful when you operate it. We clamped the wood pieces on the lathe bed and pushed the pieces slowly toward the blade. Next, we first smoothed out one side of all the trapezoidal wooden pieces, and then we clamped another wood piece on the lathe bed for positioning, against which the second piece of wood to be smoothed out could be placed. This way made sure that all the pieces could end up with the same width of the intended trapezoid.
Gluing & Smoothing
After cutting, we assembled the three layers one by one using glue, before fixing them with rubber bands for drying.
The rubber bands could be removed the next day. To smooth out and level the surfaces, a surface planer was not recommended, because the size of this plank work was too small. Therefore, we used a trimming machine, coupled with the jigs we built in other projects（連結[a2] ）. After the surfaces of the three layers were all done, it was time for assembly with glue.
First, fix the lathe faceplate onto the wood piece for positioning, rotate and, put on one side of the lathe. Press the wood piece you are about to work on against a thimble, so that the piece is firmly fixed and will not slip out. Turn the bowl around slowly until the outside of the bowl is done and mold out a cylinder at the bottom of the bowl, so that a fixture can be used to hold the bowl. It makes it easier to work on the inside of the bowl, because the closer it gets to the rotating axis, the harder it will be. We used the biggest drill bit we could find to dill the piece into a bowl shape, and the drill slipped a bit due to the force created being too strong upon drilling through the bottom. We clamped the bowl back to the right position and continued with the rest.
A floor type lathe, in comparison, is very stable and does not shake easily.
After the shape of the entire bowl is almost done, we used sandpapers ranging from 80-grit to 150-grit to smooth out the small dents on the surface, which took quite much time. After that, the 240-grit or 360-grit ones were used to gently smooth out the rest of the surface.
The hardwood plank salad bowl was finally completed, and the end product turned out even more beautiful than expected.