Such is the temptation of repeating tasks in woodworking, that I was encouraged by my editor to undertake something new – something more challenging. For one reason or another, I landed on turning a square bowl. The combination of creating a square object with a lathe seemed appropriately at odds. With everything have gone well so far, in this article I’m continuing to the later stages of construction, including thinning out the inside, sanding off, and finishing for that desirable glean.
This is still very much an experiment, so please do bare with my thoughts about how to overcome challenges – I do, of course, hope that such illuminations will be of use to you. So far, with a cautious approach, the process has been enlightening, and I have managed to overcome every obstacle with some form of inventiveness. Will it continue? We’ll see!
Finishing cuts
With the curve looking good and the edges finished crisply, I need to take a couple of finishing cuts to leave a perfect surface ready for sanding. There are two main options here: a push cut or a shear cut. My preference is nearly always a shear cut. The body position needed for a shear cut allows great visibility of the overall shape of the bowl, unlike the push cut, which I find restrictive. As the tool is against my body throughout the shear cut, I have better tool control.
Having perfected my body movement to cut the curve with the pull cut, the slight change of presentation to the shear cut makes it easy to continue the same sweep and finish the underside of the bowl. A shear cut uses no bevel contact – just a razor sharp edge, presented at around 45° to the surface. It looks and feels a little strange to begin with because the flute is almost facing the wood, but the fine shavings that are produced show how well this cut works.
Sanding
Great care is needed for sanding; those wings are very unforgiving to anything put near them. My preference for sanding bowls is always to combine hand and power sanding, which I find gives the best control and surface finish. Here I am sanding the solid centre section with standard hand sanding techniques. Then with the lathe stopped, I use an orbital palm sander to smooth and blend the wings. I finish with abrasive on a cork block, sanding with the grain to 320 grit. I also take this opportunity to sand the edges of the bowl.
Turning the inside
With the bowl turned around in the chuck, I draw a pencil line of the curve I am aiming for. Mark’s original bowl was only 5mm thick; I decide that there is little point making my first square bowl any more difficult than it needs to be. Luckily I’m not keen on overly thin bowls. So I aim for a consistent measurement of around 8 to 10mm. I mark this on two faces, and I’m pleased that I can see these marks quite clearly while turning. I deliberately leave extra waste wood above the final surface for a few more practice cuts. As before, positive cuts work best, moving forward steadily and smoothly. The technique I use here is particularly suited to thin walled, large or wet wood bowls.
Starting at the rim, the cuts focus on the shape, thickness and finish of the first inch of the bowl. Once this is done satisfactorily, the cut can progress to the next inch and so on until the turning is complete. The main advantage of this technique is that the bulk of the bowl remains for as long as possible, helping to resist flex and movement before it is absolutely necessary. I also find that, because my focus is on a particular area, it gives me the best chance of achieving a consistent wall thickness without cutting through the bowl. Regular checks are needed and once the cut is within the solid portion of the bowl, callipers are used to maintain an even wall thickness. The turning at this stage becomes just the same as for any other standard bowl.
Sanding again
As always, there is more sanding required and the process is similar to the outside. I power sand the solid portion, then switch to my cranked drill to power sand the wings with the lathe stationary. This cranked drill is easier to use single handed than a normal drill. The sanding is finished off with abrasive wrapped around a cork block, as before. I find the square edges are incredibly sharp, so soften them with 320 grit.
Reversing the bowl
This is done using the same technique I use for all bowls. I pad the chuck with folded paper towel and hold the bowl between this and the live centre, essentially between centres, turning away the holding spigot. The tiny nib that is left is carved and sanded away. I finish the bowl with several coats of hard wax oil.
Conclusion
I have enjoyed making this bowl which has thrown up some interesting challenges. I have been able to solve these using techniques that I already knew from various areas of turning and woodworking. I think this proves, if proof were needed, that having a good and wide knowledge of techniques is the best base for making any turned project. If I were to make this again, I would have a better understanding of how the shape is formed and the relationship between the initial blank and the end result. On this bowl I have lost a lot of the olive ash colour and figuring because of this lack of vision and understanding. Next time I would hope to maximise this timber better, but overall I am pleased with the outcome.
