Monday 9 July 2018
I decided to make this project after seeing the September issue of Coombe Abbey Woodturners' Club newsletter, which gave advance notice of last Christmas's competition. One category was toy making, which had to be 90 per cent turned.
This project came about having helped a new club member set up his first lathe. We were having a cup of tea when his wife – who is from Japan – joined us. I told her how, two years ago, I had seen a demonstrator at the AWGB seminar – who was also from Japan – and how impressed I was by the quality of his work and the Japanese method of turning bowls.
I was then shown a set of bowls of the same high standard, and also a toy called a Kendama: 'Ken' meaning sword and 'Dama' meaning ball in Japanese. I was then given a demonstration on how to use this toy. I quickly learned that using the Kendama effectively requires a lot of dexterity and skill.
There and then I decided I would make a Kendama to enter into the club's Christmas competition. The Kendama is a variant of the cup and ball, but here, you have three cups to aim for, and a spike. It really is the ultimate challenge.
In my opinion, this project involves most of the basic elements of woodturning. Using/playing with this toy will test your hand and eye coordination, which will also improve your turning tool manipulation. I hope you agree. In addition to the turning tools mentioned opposite, you will also need 12.7 and 9.5mm drills, a No.1 Morse taper reamer, Vernier callipers and a steel rule.
Turning the sphere
Cut your chosen blank to the following measurements: 60 x 60 x 90mm long and cut your sphere template from a piece of card or plastic – used to check the profile later. Mount the blank between centres and turn to clean up the diameter. You will also have to turn a spigot to suit your chuck. Hold the spigot in your chuck, using the tailstock for support. Face the end square and turn 55mm dia. Mark off as per the drawing on page 67. Lightly cut a 'V' on the centre and colour or burn it as a reference. Use a 3mm parting tool to cut the positions and diameters accurately – again, see drawing
Use the skew chisel to roughly shape the tailstock side of the sphere. Now do the same at the headstock end, but don't cut the sphere off as you now need to refine the shape. Use your preferred gouge to turn and refine the shape, linking up the reference points cleanly…
… now check it with the sphere template and adjust as necessary
Use a skew chisel to cut a small cone section in the tailstock end of the sphere, 18mm or so wide and about a 120° angle – this will ensure that the drill locates and runs true. Hold a 12mm drill in a Jacobs chuck and drill to a depth of 45mm
Once drilled, turned, and the tapered bore sanded and finished, part off. Turn a spigot on the stub left in the chuck – to create a push fit in the sphere. Mount the ball and use the tailstock centre for support, then finish turning the sphere. Drill a hole to suit the cord you are using, then you can sand, seal and polish
Turning the shaft
Cut a blank to the following dimensions: 50mm square x 180mm long. Place on the lathe between centres, turn to a cylinder and create a spigot for your chuck. Now remove it and hold it in your chuck with the tailstock for support. Turn it to a diameter of 42mm and use a 3mm parting tool to form the position and the diameters of the three fillets…
… then finish the outside form of the cup and cut the cove, bead and fillets with a spindle gouge and parting tool, as necessary
Roughly shape the internal cup, remove the centre support and finish the form using a scraper. Lightly undercut the inside rim leaving a land/rim section of about 2mm-3mm wide so as not to fracture or chip when the ball hits/lands on it, then you can sand, seal and polish the cup interior
Take some tissue paper and foam and place in the cup for protection, bringing up the tailstock for support and refine the tapered shaft section, linking up to the 12.5mm and 10mm diameters of the taper. Lightly sand and take care NOT to round over the fillets. Finish turning the taper down to 8mm dia. Lightly sand then seal and polish. Cut a couple of 'V' cuts near the cup and burn them with wire. Round off the end of the shaft near the headstock and almost part it off. Remove the tailstock support and part off, then seal and polish the radius
The double-ended cup
Cut your blank to 50 x 55 x 75mm long, mark off the drawing, and centre the piece accurately between a friction drive plate and a revolving centre in the tailstock. Turn a spigot to suit your chuck – 5mm (3/16in) long – and make your blank 50 x 50 x 70mm long
Hold the spigot in the chuck and drill through 9.5mm, then counter drill to a depth of 12.7mm diameter x 12mm deep. Either use a 1 Morse taper reamer – held in the tailstock to create the taper – see the drawing for this step, or drill 9.5mm and 14.5mm at the correct depths and use a 6mm diameter skew chisel to bore the taper by linking up 14.5mm and 9.5mm diameters
Hold the piece between centres and turn a spigot to suit your chuck. Reverse and hold it in the chuck. Turn to a diameter of 46mm. Finish turn the form past the centre line before forming a 'V' and adding a burn line. Use a spindle gouge to shape the cup, turn the radius on the rim, then sand and seal the outside. Once the end hollow and cup are fully formed check that the main shaft fits nicely and that everything is proportional, then protect the outside of the cup with masking tape. Hold in the chuck and repeat as for the previous operation. You now need to mark and burn two lines, check the fit of the sphere in the cup, and then sand, seal and polish, as before
With the pieces all turned, thread your cord through the hole in the ball and knot the cord at both ends. The cord needs to measure 1-1.5mm diameter x 300-350mm long. Seal each of the knots with Cyanoacrylate adhesive. Pass the free end of the cord through the tapered hole from the small diameter. With the large cup uppermost push the shaft through from the other end, trapping the cord on the centre line on the right-hand side of the hole. If you are left-handed, you can trap on the opposite side
And here is the finished Kendama toy in action