Weekend Projects - Three-cornered Bowl archive

Friday 8 May 2015

Nikos Siragas creates a three-cornered bowl, which requires the use of both carving and turning techniques

Gallery

I demonstrate each December at various clubs in the UK and prefer to show something different each time, particularly when visiting a club I have been to before. Consequently, a few months before my demonstrations are scheduled I start racking my brains trying to think of a new idea that complies with the following requirements: it must involve both turning and carving, it mustn't be too difficult for the average turner and its basic design can be completed within around an hour.

The idea for the three-cornered bowl arose from this brain racking. In 2007 the three-cornered effect was used on a vase and in 2008 I had progressed to putting it round the top of a bowl. In this article I am going to show you the bowl design, but the carving can be applied to a vase in the same way.

Tools used:

Boring bar with scraper and cutting tips

Skew chisel

6mm round-nosed scraper

10mm spindle gouge

12mm bowl gouge

Microplane round rasp

STEP 1

Take a piece of olive wood (Olea europaea) with a cross-grain to take advantage of the colourful centre. You can also use any other hardwood, either cross- or end-grain. You need a fairly compact wood to get a good result with the carved element. You should be aiming to make the bowl around 150mm wide x 100mm high

STEP 2

Roughly shape the outside of the piece with a bowl gouge and then make the chucking base. Here I am using a skew chisel - I tend to measure by eye, but if you are not sure, then use callipers to get the correct diameter

STEP 3

Fit the piece into the chuck, tighten well and clean off the top of the piece with a bowl gouge to give you a level surface to work on

Hollowing out

STEP 4

Starting from the centre of the wood, begin to open up the bowl using a hollowing tool, or bowl gouge, if you prefer. If using a hollowing tool you should be moving the cutting edge in a smooth, sweeping motion from the centre outwards and the cutting head should be set so that the head straight is in line with the blade and have the cutting edge presented to the wood at about 8 or 9 o'clock - position of the numbers on the face of the clock - leave the walls thick so you can then return to the outside and continue shaping as necessary later. Reduce the wall thickness to a bit more than 10mm. Leaving the walls thick will allow you rectify any mistakes you may make later. Use a scraper to smooth out the inside surface of the bowl. If you use the scrapers as in the photograph opposite you should have the cutting edge angled to the wood at about the 8 or 9 o'clock position. Start from the outer edge and move inwards, moving smoothly and steadily across the centre of the bowl to avoid getting any bumps in the centre. Continue until you have a wall thickness of about 10mm. Use callipers and check that you have an even wall thickness throughout the piece

Marking out

STEP 5

Now you need to mark out the three corners of the design and to do this I suggest you use a disc mark, as shown, held in place by the tailstock. It is a simple way of getting the design evenly spaced on the bowl. The disc must, of course, be a little smaller in diameter than your bowl. Note the disc has an equilateral triangle marked on it. The points of the triangle are the positions at which to mark the bowl

STEP 6

Draw a line around the bowl, about 20 or 30mm down from the top edge, and then mark a line from the top edge at each of the three corners to join this line. This marks the depth of the carved element, you can of course choose how deep you want the design to be; the deeper it is, the more dramatic the piece will look

STEP 7

The bowl is now divided into three sections. The next step is to draw a diagonal line in each section from the top edge to the opposite bottom corner. Firstly, cut downwards at each marked 'corner' using a thin saw and then cut diagonally, carefully removing the excess wood

Shaping the three corners

STEP 8

Using a round Microplane rasp start shaping the outer curve, using even strokes to remove the wood evenly and without applying too much pressure

STEP 9

Note: the angle at which I start rasping in the previous step - this ensures that more wood is removed to give a deeper curve at the edge and this gradually tapers off as you move round the bowl, so that it becomes a shallower curve

STEP 10

Apply a flat rasp to the top edge and set it pointing slightly downwards towards the centre of the bowl to give an angle to the top edge. This should mirror the outer curve

STEP 11

When the main shaping has been completed start cleaning up the outer edge of the bowl and make the walls thinner. Using the bowl gouge start at the top edge lower point and move the gouge downwards; you will be left with a 'lip' where the carved element joins the turned part. Here you can see the shape we are aiming for with the top edge: a distinct curve on the outer edge complemented by the inner curve along the top edge

STEP 12

Remove the 'lip' with a flat rasp; ensure that you are constantly checking the line of the outer wall so that your rasping smoothly integrates the curved top edge with the turned bowl sides. Use your fingers on one side and your thumb on the other side of the bowl wall to feel where there may be distortions – check this with callipers

STEP 13

Return to the inside of the bowl and use a scraper to smooth out the inner wall as it joins the rasped section, thinning the walls of the bowl a little more. Start from the outer edge and move towards the centre. When you finish, test the smoothness of the shape of the inside of the bowl by running your fingers from the edge down and across the centre. You should get a smooth curve with no apparent ripples or bumps

Finishing

STEP 14

Combining turning and carving produces some fascinating shapes and rasping is a quick way to shape. Unfortunately this means there is a lot of sanding required for the shaped elements. Start with an 80 grit round sanding tip attached to a Dremel for the rasped sections and then move on to sanding pads attached to a drill for the rest. There is usually some hand sanding for the corners and other bits that the power sanders miss, so check your work carefully to make sure nothing is left unsanded. Go up in stages so you eventually end up at 1,500 or 2,000 grit – this gives an extremely smooth surface and produces a very good finish

STEP 15

Apply your finish on the inside before reverse-chucking and allow it to dry well. Use several coats of Danish oil or sealer, applied with a brush and the excess wiped off. When off the lathe buff with Carnauba wax

STEP 16

For reverse-chucking shape a polystyrene block that has been glued to a wooden 'faceplate.' This makes sure there is no damage to the inside of the bowl

STEP 17

Complete shaping of the bottom section of the bowl, bringing it down to a nice small foot. A small base always makes the shape of any turned bowl look more delicate and a simple measure is at least one-third of the diameter of the top of the bowl

STEP 18

Clean off the base with a small round-nosed scraper and make the base slightly concave. Apply a finish, part off and you have a simple but effective design. Here are several different finished examples


Briony Darnley

Tagged In:

Nikos Siragas , Weekend Projects


Diagrams Click an image to enlarge

Handy Hints

1. Before I start turning I usually sand down the toolrest to ensure it is smooth and I then polish it with paraffin wax. Clean the lathe bed regularly with olive oil as this protects the metal to a degree, especially from timbers such as fresh olive wood, which I use a lot for my turnings
2. A small base always makes the shape of any turned bowl look more delicate. A simple measure is at least one-third of the width of the top edge of the bowl. I always make the base slightly concave as I find this helps the bowl or vase sit more securely on a surface. Use this as a guide when you are planning the designs of your turned bowls