Multi-Axis Turning

Multi-Axis Turning:
Richard Findley explores multi-axis turning for the first time

Multi-axis turning simply means that during the turning process of a piece of work you will hold it on more than one centre point, and some quite fantastic shapes can be created using this technique. During my early years in turning, when it was just a hobby, I never explored this area of turning, partly because it always seemed rather complicated and partly because other areas interested me more. Now, as a professional, I am yet to be commissioned to make an item like this, so it remains an unexplored avenue for me.
This article will give me the opportunity to have a play with the techniques involved and see what I can come up with. The only item I have previously made using this technique is a walking stick handle, which I demonstrate from time to time, but this is very basic stuff compared to the potential of this technique.

The theory
Multi-axis turning in itself shouldn’t be particularly difficult to do, the hard part is going to be working out what shape will be achieved by moving and adjusting the work between several centres. This is the part that has always made my head hurt. My intention is to explore two different styles of multi-axis turning, combined within a single project. I expect to have to carry out some trials to find the best mounting points to achieve the desired results, but I’m hopeful that I can pull it off. We shall see! 

Inspiration
When looking at this sort of work, one name is before all others in pioneering multi-axis turning: Jean-Francois Escoulen. I have previously written that, when looking for inspiration in a particular area of work, you should always look to the masters in that field and Escoulen’s work is sure to do just that. I remember sitting in on one of his demonstrations at an AWGB seminar, back in 2009 and seeing him ‘warm up’ with a little multi-axis cork screw handle, which appeared so simple and yet complex at the same time, while being a perfectly ergonomic shape for the job it was designed for. Coincidentally, at the same seminar was a Norwegian turner, called Petter Herud, who made a box with faceted sides, using a similar and yet different multi-axis technique, this made a real impression on me. I was reminded of this by an Instagrammer that I follow called Chris Hoehle from the USA, who recently made a box using similar techniques, which brought these memories to the front of my mind at a very useful time.
My notes from the seminar are long gone so it is going to be a case of trial and error until I manage to match the techniques with the image I have in mind. I decided to make some notes and sketches of my idea, based on the inspiration mentioned above. A box with ‘square turned’ sides, which will need turning on five different centres, with a domed lid and a finial in a contrasting timber which will also be turned on at least two centres, which will use the technique in a different way.

First practice
It seems obvious to begin with the box body. All I need to do is find four equally spaced centre points which will form a square shape once turned. As always, I use my marking gauge to scratch a cross on the ends of the spindle blank to find the true centre and immediately it becomes clear that all I have to do to find my four points is to measure along these scratch marks to four points equidistant from the centre, but how far from the centre should I go? My blank is an offcut of tulip, 75mm square, so plucking a measurement out of the air, I use a compass to draw the curve that would be created by turning at 25mm out from the centre. Immediately I can see this will mean the blank is spinning wildly off centre, so I try adjusting to 20mm from the centre to see if it changes the curve much. It doesn’t, so my first attempt is set at four sets of centres, 20mm from the actual centre of the blank.

With the blank held firmly between centres I start slowly and gradually build up the speed to a point that I feel comfortable, and take some initial tentative cuts. Because there is so little wood coming into contact with the edge of the tool, the cut is light and easily controllable. As I removed material I began to wonder when exactly I should stop turning. On closer investigation I realised that the lines I had drawn on the end grain with the compass showed up quite clearly on the spinning work. By the time I fully understand how easy this process is I have already turned two sides, slightly unevenly, but by the third and fourth, I grasp it.
I quite like the result of this first trial, the sides are suitably square and yet curved, if slightly uneven, but I’m curious to see what would happen if I move the drive points closer to the actual centre. On a second tulip blank I set the centres at 10mm from the true centre, this time taking extra care to clearly mark out the curves of the four sides with my compass. Armed with the experience of the first trial, I now take extra notice of my blue marking out lines and the result is much more crisp, but I’m less keen on the tighter curved sides produced, so I now know that, on my final box I will go for the 20mm off set. Looking over my two trial turnings, the pattern made by my Evolution drive centre makes me smile. It’s funny the patterns that present themselves, almost by accident.

Health and Safety
I use a 1950 Wadkin RS8, which is a very large cast-iron machine weighing in at around 3/4 of a ton, which means that large off sets are possible without creating vibration. This sort of off set on a mini or midi lathe could potentially be dangerous, causing dramatic vibrations. I would suggest beginning with less off set and keeping the speed low, initially at least, and building up until you feel comfortable and the lathe is running smoothly. I also use ring type centres to drive and to support from the tailstock end, to give maximum support throughout the turning operations.

The box
My plan is for a pale coloured box with a darker finial, so after a rummage through my various timber stacks I find a clear piece of ash which fits the bill perfectly. In my box of exotic odds and ends I find a blank 22mm square and slightly bigger than a pen blank, in cocobolo, which will be ideal for the finial, which I shall come to later.
I am still unsure exactly how tall to make the box, so cut the blank over long at 125mm and carefully mark it out as before, only with extra care. I turn it with my large spindle roughing gouge and then take a couple of careful passes with a skew. I decide that sanding with the lathe running is out of the question, I’m sure it will destroy the crispness of the corners, so a skew finish followed by some hand sanding is going to be the way forward. The sides of the box are dead straight, so I line up my toolrest with the lathe bed and use this as a fence to help me maintain a smooth and straight cut.
With the four sides turned and smoothed with the skew I carefully inspect them and make sure I’m happy with how even they are. The two trials really paid off and this third attempt is pretty close to perfect. Satisfied, I can now remount the box on its actual centres and turn a holding spigot in the
base. From here it simply needs hollowing as a standard box, most of which I do with my 12mm spindle gouge, I use my Hope carbide tool, which enables a longer reach and cuts cleanly on end grain. A square ended negative rake scraper finishes it off nicely and allows me to cut a crisp square recess on which to seat the lid.
While working on the box I decide that it would probably look best as a ‘cube’, so mark it up at 75mm tall and use a jam chuck to finish the bottom properly. The final step is to hand sand the ‘square’ sides, which I do with abrasive wrapped around a cork block, taking it down to 400 grit.

The lid
While not multi-axis turned, I thought I should explain how I turned it as it is an important part of the design. I want a hemispherical dome for the lid, but want the curve to start at the point where the curve meets the box body, so I cut a 5mm straight section first, which will sit in the recess on top of the box, before beginning to cut the curve of the dome. I plan to hollow out the underside but need to be able to hold it safely, so I dry fit the lid to the box and begin to shape the dome, while leaving enough timber at the top to form a holding spigot. Once I’m satisfied that the curve is progressing well I turn the lid around, holding it in my chuck and hollow the underside. Rather than trying to keep an even wall thickness on the dome, I deliberately leave the top thicker, so I can drill it to mount the finial, but strive to keep the curve smooth and not leave it unreasonably thick. I think I have the balance about right.
With the inside of the lid refined with a curved negative rake scraper and sanded smoothly I remount it between a waste wood block and my live centre, effectively holding it between centres, and complete the curve of the lid, which I check with a template made from thin MDF, down to a tiny nib which can be easily
carved and sanded away. I then drill the top with a 4.5mm drill, ready to mount the finial. 

The finial
I know roughly how I want the finial to look but actually achieving it my be a different matter. There are distinct similarities between the finial and the walking cane handle that I have previously turned so, based on this principle I decide to give it a go with some more scraps of timber. I prepared some sections of sapele the same size as my piece of cocobolo and make another sketch of my intended design to see if my attempts come anywhere close.
The first shape is best described as a trumpet, turned on the actual centre of the block. With this shaped I mount the tailstock end on a new centre, about halfway toward the diagonal corner of the blank, while leaving the drive end on the true centre. Next I turn the curve onto the top of the first trumpet and begin to shape the second, smaller trumpet. At this point I realise I have turned my first trumpet too thin, because it snaps, but I’m encouraged by what is taking shape and so try again, this time leaving the base a little thicker. This time it snaps at the top because I turn the smaller top trumpet too small.
My third attempt is an improvement again and works well but for a small chip out of the grain, a fourth and final trial, which I am able to dry fit to the box lid to see how it looks in proportion to the rest of the box, and I now feel ready to have a go on the real thing. My piece of cocobolo is long enough to give me two attempts, but straight off the back of this fourth trial I’m confident it will work.
The dark cocobolo is difficult to see spinning on the lathe, small and blurred as it is, so I place a piece of white paper on my banjo, which really highlights the profile of the finial. As before, when I turned the box body, I am using my Axminster Evolution drive centre and Oneway live ring centre, to give maximum support and drive on this dense timber. I sand each section as I turn while there is still strength there, although I expect the cocobolo to be much stronger than the sapele that I used in the trials. Being so dense, I sand the cocobolo down to 1200 grit which leaves a supremely smooth surface which I think will contrast nicely with the strong grain and pale colour of the ash.
Back on the true centre, I turn the top curve of the finial down as small as I dare and make sure the bottom is the correct size to fit the lid, before removing it from the lathe and cutting away the waste with a hand saw and finishing the top surface by paring with a sharp chisel and sanding by hand. 

Finishing
All that is left to do is to assemble the lid and finial, which is simply a case of carefully spreading some wood glue in the drilled hole in the lid and pushing the finial tightly into it. Once dry I use satin acrylic lacquer and spray several coats on all surfaces, lightly cutting back before adding the final coat.
I choose acrylic lacquer because it should have the least effect on the pale colour of the ash, giving only a colour change similar to that of wetting the surface.    

Conclusion
I was really pleased with how closely the end result matched the idea I had formed in my head. It is always very satisfying when things actually go to plan. There is always room to refine and tweak the overall design, but on the whole, I am pleased with how this little box turned out. The trial pieces were vital in helping me understand how the various mounting points affected the shapes that were formed and overall, I feel like I have a better understanding of multi-axis turning, although I equally feel like I have a lot still to learn. This box could be made in any number of variations, including changing the number of sides down to a three sided triangular box or an eight sided octagonal box perhaps? You could even introduce a twist by mounting the box differently at each end. The possibilities are endless and I have just scratched the surface with this box.
This has been an interesting and fun change from my normal production work and I’m sure that the experience will be logged for later use, somewhere along the line. Next month I will continue my journey into multi-axis turning with some experiments with some commercially available eccentric chucks.