Below are the first three photos of the blanks cut to shape and cut through on the table saw at various depths to produce the shape of the inside of the bowl.
As I carry out each process, I will take photographs for inclusion into this, an on-going blog.
The bowl will (hopefully) be finished during the course of this coming week.
The softwood block visible in the photos is simply PVA*2 glued to the outside surface of each of the four sides, to enable each of the sides to be held firmly in the vice, as the inside surface is being shaped to a pre-cut thin wood profile; and the groove formed near to the bottom edge, to receive adhesive applied to the base of the bowl.
Day 2 ~ Monday
Today started by producing the curve to the inside faces of the four blanks. Just to clarify, from yesterday’s work :- The depth of the table-saw cuts, along the grain of each of the sides, is determined by drawing the finished profile onto the end grain of the blanks; then ensuring that none of the saw cuts touch the line. It sounds time consuming and fiddly, but it’s not actually. The best way to produce consistent results with each of the blanks, is to position the fence for the first cut – set the saw for the depth of cut – then cut each of the four blanks, before moving the fence outwards and reducing the depth of the cut. Simply remember to cut all four blanks before altering any of the settings. Because of the profile of the curve, it is possible, at a specific point, to begin producing saw cuts from both the long (top) edge and the short (bottom) edge, thus doubling the rate of progress.
Right. back to today
I suggest that you will need the following tools.
You can manage with a large bevel edged chisel and a mallet, but it is much easier with an electric planer. This cuts quickly, and effectively, through the material which remains between the saw cuts. Obviously care must be taken as the removal of the timber gets close to the bottom of the saw cuts, but there is nothing magic about. A shallow setting on the planer is the answer – this simply requires more passes over the timber. Once the bulk of the material to be removed has been dealt with, it is time to use the smoothing plane. Particularly with a timber like oak, where you may encounter cross or reverse grain, a shallow setting is again preferable. Keep checking the shape with your thin wood profile. I marked the top of mine to ensure that I didn’t pick it up and try to apply it to the blank the wrong way round.
The profile is such that it would be immediately obvious, but ………….
(you will see the profile and the Top mark in one of the following pictures)
I also found the block plane to be very useful too, when dealing with reverse grain.
When you’re satisfied that the profile fits the shape that you’ve produced, the orbital sander makes easy work of any residual plane marks.
The photo below shows each of the four blanks shaped to the profile (which is at the bottom of the picture) a small square for transferring lines across the top and bottom edges of the blanks and a sliding bevel, set to 30°, which is the slope of the sides of the bowl when assembled.
The next task is to ensure that each of the blanks is exactly the same size and shape, otherwise they will not fit together accurately and the mitre joints will have gaps in them.
The next photo shows two of the blanks (one having been marked as the pattern [‘Patt‘]) which are placed together (mirror-imaged) to ensure the the base dimension is exactly the same. Once any discrepancy in length is marked on the blank to be worked on, the cut along the end grain can be marked out with the pre-set sliding bevel.
The end grain on each blank is now planed with the smoothing plane to the lines.
A regular check against the pattern blank, as work progresses, ensures that the required accuracy is produced.
Tomorrow’s work is to plane the end grain edges at the mitre angle (which, it should be noted, is not 45° ~ even though it appears so on the finished article #1) from the straight outside edge of each end of all four blanks, and glue them together to provide the outline shape of the bowl. To enable the sides to be tightly clamped together around the sloping surfaces and the corners, whilst the glue sets, will require a framework which will enable me to apply picture framing clamps to the top and bottom edges. I’m going to have to make (whatever I come up with) tomorrow afternoon, before I can even contemplate gluing the bowl together.
So it may be Wednesday before I return with details and photos of the assembled bowl, and the clamping frame.
Then it will be on to the lathe with the piece of oak that I’ve selected for the base as, though it will be square to fit into the bottom of the bowl, I want to put a small circular dishing into the inner surface, and a circular recess into the underneath face, to set a circular piece of baize into, to protect the glass surface of the dining table.
Oh, and the observant amongst you, will have already noticed (from the 2nd of today’s photos) that two of the sides have large portions of much more prominent heartwood*5 visible. So I’m going to have to consult with the client to determine whether those blanks are placed adjacent to one another, or opposite. But I’ll probably have to have made the framework first, so that the bowl can be assembled ‘dry’, to enable the client to see what effect the two options produce visually.