Multi-axis Turning: The Making of Kilkea
The name Kilkea is taken from the hometown of Ernest Shackleton, an Anglo-Irish explorer. I have used references to Antarctic explorers before to name some of my other pieces; it is a connection to an interest of mine. Shackleton’s story is well worth reading. It is also the name I gave to one of my most challenging pieces of multi-axis turning. In this article, which I wrote for American Woodturner, I describe the stages I went through to create an award-winning piece.
The concept for Kilkea evolved from a design that was considerably different from the one featured in this article; its development is an example of how a technique can be the impetus for new creations. The starting point was a sketch I made in 2004 of a simple boat-shaped bowl. The shape was simple; however, the process to make it proved problematic.
As I worked through various problems, I produced many forms that I did not like, as well as some that had potential. As I refined the technique, I began to have more success, but more important, I started to see the design possibilities. Kilkea is a far cry from my early attempts, and is the result of much exploration.
The name Kilkea is taken from the hometown of Ernest Shackleton, an Anglo-Irish explorer. I have used references to Antarctic explorers before to name some of my other pieces; it is a connection to an interest of mine. Shackleton’s story is well worth reading.
Sound competency in tool techniques and knowledge of woodworking methods are required for this project — it is complex. Additionally, it will take quite a lot of time to complete. Kilkea took approximately thirty hours and is the largest piece I have made using this technique. I recommend that you first try this process on a smaller scale.
You will need wood glue (I used PVA, a form of yellow glue) and plenty of scrap wood — I used radiata pine, a timber I have in abundance and in large sections. The timber used to make the actual piece, good wood, was a 6″ (15 cm) square of fiddleback red gum that was 18″ (46 cm) long. (You might want to try a piece that is 2″ [5 cm] square and 6″ [15 cm] long.)
To begin, cut the good wood to length and dress two opposite sides using a jointer. Glue and clamp enough scrap wood to the sides of the good wood to create a diameter of 18″ (46 cm) (Photo 1). After the glue cures, you will cut a disc, but before cutting, carefully measure the width of the good wood to find its center (Photo 2).
With the center carefully located, draw an 18″- (46 cm-) diameter circle (Photo 3) and cut the disc on the bandsaw (Photo 4). Attach an 8″- (20 cm-) diameter faceplate to what will become the top surface of the final piece, making sure the disc is centered on the faceplate (Photo 5). Use a large faceplate to bridge the good wood so that the screws will be screwed into the scrap wood.
Turn the disc and the underneath
Kilkea has four turned surfaces: (1) the top, including the bowl, (2) the underneath curved void, (3) the front, and (4) the back. The top and underneath surfaces are turned on one axis and the front and back surfaces are shaped on a second axis.
Turning starts with work on the area that will be the underneath surface of the finished piece and the first step is to turn that surface flat.
Next, I turn a simple hollow shape (curved void). I took the depth and diameter measurements from a scaled drawing I made prior to starting the project. I made this bowl 9″ (23 cm) wide and 2″ (5 cm) deep.
Mark a line to indicate the diameter of the curved void (Photo 6) and hollow out the underside of the piece (Photo 7). Keep an eye on the depth. After the desired amount of wood is removed, sand the interior of the hollowed-out area.
A flat base is required for the bottom of the wings of the final piece, so check the outer rim of the bowl using a long straightedge (Photo 8).
Turn the top
Turning the top of the piece is next. So that you can reverse the disc and remount it onto the lathe, screw a piece of hardwood onto the bottom using the scrap wood of the disc as the attachment points (Photo 9). The scrap hardwood should be at least ¾” (20 mm) thick and the same length as the diameter of the disc.
Attach a faceplate to the scrap wood board. The use of a reversing mandrel helps to ensure that the faceplate is centered on the disc (Photo 10).
With the faceplate screwed into position, flip the piece around, screw the second faceplate onto the headstock, and start shaping the top surface (Photo 11).
I start by turning the small bowl (Photo 12) and then shape the curve in the top (Photo 13). This curve is kept minimal in order to make subsequent processes simpler. After turning, sand these surfaces, including the small bowl.
Cut a small step that will accommodate the lid. To cut this step I use a sharp skew chisel as a scraper (Photo 14). By using a skew chisel in this manner, I am able to cut the step cleanly enough to avoid any sanding, which keeps the edges clean and crisp.
The turning is complete on the top and underside. Take the piece off the lathe and cut the scrap wood away from the good wood using a bandsaw
Make a carrier
The next stage of the process does not involve the good wood, so put it aside while you make a carrier. The carrier is another block of laminated scrap wood that the good wood gets glued to so that the good wood can be turned on a second axis. Glue together sufficient scrap wood to create another disc that measures 19″ (48 cm) in diameter and about 3″ to 4″ (8 cm to 10 cm) thick (Photo 16). Allow the glue to cure before cutting the block into a disc.
Mount the disc onto the lathe, using the faceplate (Photo 17). Later in the process, the top surface of the good wood will be glued to the carrier and for this to be possible, a negative of the top surface of the good wood
needs to be shaped into the surface of the carrier.
When I first started making these pieces I thought that matching the carrier to the previously turned good wood would be a difficult process but there are some simple techniques that help make it reasonably straightforward. The first is to understand that the high points on the good wood will be low points on the carrier and vice versa. I start by measuring the length between the high and low points on my good wood (Photo 18).
I also measure the distance from the center to the low point and transfer this information onto the carrier by drawing lines that indicate the low point. Lines are also drawn for the diameter of the bowl and the outside diameter (Photo 19).
Shape the carrier using a bowl gouge and/or scraper. I do not concern myself with cutting cleanly; however, it is important to establish the low point on the carrier and the maximum diameter it needs to be (Photo 20). Because the top curve of the good wood is kept simple, creating the negative of it on the carrier is not too difficult. Keep the good wood close by and as you get closer to the final shape, regularly stop the lathe and check the fit (Photo 21).
The fit does not need to be perfect because an application of hot melt glue will act as gap filler.
With the carrier shaped, another piece of scrap wood is needed to fill the void on the underside. Shape this using the same technique (Photo 22). There is no need to sand the surface.
Attach the good wood to the carrier
To attach the good wood to the carrier, I use hot melt glue, which lets me separate the two after the turning is complete (Photo 23). A problem I had with my early attempts was the good wood separating from the carrier while spinning on the lathe, so I had to find a means of making the hot glue stick better. I discovered that the hot melt glue was cooling too much before I could bring the two pieces together, compromising the adhesion. My solution was to apply the glue to the carrier using the glue gun, and then heat the glue using a flame (Photo 24).
With the glue almost at the point of combustion I quickly position the good wood and apply pressure to the two surfaces (Photo 25).
The plug to fill the underside void is attached in the same manner (Photo 26).
Take the assembly to the bandsaw and remove the excess wood on the sides (Photos 27, 28).
Build up wood for second disc
The carrier and good wood spin on a second axis so you need to build up the assembly with extra timber to create another disc (Photo 29). The shape of the final piece can vary quite a lot depending on how close the good wood is positioned to the center of the new axis. I positioned the top surface of Kilkea close to the center of the axis, which made the sides close to parallel. In other pieces I have made the bottom close to the outside rim of the disc with the result being sides that curve more distinctly inward (Figure B).
Mark a center making sure the center point is positioned in the scrap wood. Draw a circle (Photo 30) and take the glue-up to the bandsaw and cut out a disc.
Turn the front surface
I use a screw chuck to mount the disc onto the lathe. The hole for the screw can be drilled accurately using
a drill press. However, this disc was too wide for my drill press, so I used my hand drill for the job (Photo 31). I do not drill the hole all the way through, preferring to drill the hole on the other side while the piece is on the lathe.
I have a faceplate that accepts the screw. Thread the disc onto the screw (Photo 32). You are then ready to turn the front surface. Turning can commence; however, another problem is encountered. The disc is poorly balanced because of the difference in weights between the good wood (red gum) and the carrier (pine).
Vicmarc has a counterbalance accessory to help overcome the problem of out-of-balanced wood. By using the counterbalance accessory, I can spin the wood at a faster speed (Photo 33). Without it, I would need to use a slower rpm.
I am now ready to start turning and shaping the front surface on the second axis. I refer to my drawing regularly while shaping the front, as I can no longer see the bowl because it is glued to the carrier (Photo 34).
As wood is removed, gaps appear between the carrier and the good wood and these gaps can result in the edges of the top surface being chipped away. I use hot melt glue to fill the gaps (Photo 35).
Finish shaping the front surface and then drill a hole in the center to take the screw chuck so the piece can be reversed (Photo 36).
Shape the back surface
I now use the screw in a four-jaw scroll chuck, which I pad to avoid any marks being made on the good wood (Photos 37, 38). Start shaping the back surface (Photo 39). At this point it is extremely important to refer to the drawing to avoid taking any cut too far.
I drill holes in strategic positions through the scrap wood. These holes help me see what the thickness of the wings will be (Photo 40).
With holes for the screw chuck in both sides of the form, you can reverse the piece at any time and work on either side. When you are happy with the shape, sand both sides. The turned piece is now ready to be taken off the lathe and the good wood separated from the carrier.
Separate the good wood
To separate the piece from the carrier, I normally put the form in a microwave oven and gradually heat it until the glue softens. This piece, however, was too large for my microwave, so I cut the carrier away on the bandsaw leaving ½” (13 mm) of scrap wood still attached (Photo 41). This allowed me to use a hot air gun to melt the glue and separate the remainder of the carrier from the good wood (Photos 42, 43).
Use the same technique to remove the scrap wood from the bottom surface. Any glue left on the piece can be softened with the hot air gun and wiped off with turpentine.
The lid, finial, and finish
The final steps are to make a lid, a finial, and to apply finish. I sprayed the top of the lid with India ink, which is what I also used to blacken the finial. The finish is Danish oil and then three coats of a matte nitrocellulose lacquer.
American Woodturner August 2010