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Disappearing Ball Trick

In an abridged extract taken from Turned Toys, the author turned a toy for a disappearing ball trick.

Table of Contents

This is a four-part, spindle-grain project that will test your skills in working to fine tolerances and disguising the joins. To help with this, you need to have some detail that will hide and obfuscate what is going on when various parts of the trick are lifted. The cup has a hollow interior, into which is placed a loose ball. Over this is placed a false cap that fits on top of the ball – it has a hollow underneath, while the top is shaped and coloured to look just like the loose ball. Therein lies the illusion at the heart of the trick. Over the top of this, the lid is fitted. For this project, it is important to work in clear stages, and to constantly check measurements and fit. It’s vital that the wood selected holds fine detail and has a very fine, almost indiscernible, grain structure. I chose sycamore (Acer pseudoplatanus), but walnut (Juglans spp.), boxwood (Buxus spp.) or fruitwoods would work well.

TIP

When refining the shapes with a scraper or a skew chisel in scraping mode, remember that delicate, light cuts will help you to achieve a nice, clean finish that requires minimal sanding.

Plans and equipment

Tools

  • PPE: facemask/respirator
  • Drive spur and revolving centre
  • Chuck
  • Spindle gouge
  • Thin parting tool
  • Scraper or shear scraper
  • Spindle roughing gouge
  • Beading and parting tool
  • Round-nose or French curve scraper
  • Abrasives, 120–400 grit
  • Bead forming tool, 3⁄16in (5mm)
  • Sphere-cutting jig (optional)
  • Angled scraper or skew chisel
  • Dye or stain
  • Satin lacquer

Making the cup lid

1. Mount the wood between centres, and use a spindle roughing gouge to turn to a cylinder of the right size. Cut a spigot at one end, then mount in the chuck. Using a spindle gouge, create a slightly elongated egg form
2. The end near the chuck will become the cup section, and the upper egg-shaped part will become the lid. On the centre line of the shape, use a thin parting tool to cut a small spigot. Part off the lid
3. Hollow the inside of the cup. I used the same hollowing technique as in the Wooden puzzle, but you might need either a multi-tipped tool with a round or teardrop-shaped cutter, or a round-nose or French curve scraper to refine the shape. The hollow needs to be hemispherical, to accept the ball. You can use a template for this. Later – when you have created your ball – if you find that the hollow is slightly out, you can remount the cup and adjust the hollow
4. Remove the bulk of the waste with the spindle gouge. Use a scraper or shear scraper to clean up the inside. Once the cup is shaped, sand the inside then gently sand the inner and outer edges of the spigot
5. If you are unfamiliar with cutting hollows to a specific size, you can make a ply or paper template to check the shape. If the hollow matches, then all is well. If it is slightly tight, as in this case, you can remount the piece and adjust. If the hollow is too big, you can either make a new cup or just increase the size of the sphere and the corresponding hollow in the false cap
6. Use a bead forming tool to cut some beads in the cup – not to full depth at this stage. You can cut them by hand, but that will be tricky on this shape. A forming tool will give the same width and shape every time. You have to control the depth of cut, so make sure the crowns of the beads flow visually. They should have no highs and lows

Making the ball

1. The ball needs to be a tight fit, but easily removed. Use the same method for this as for the balls in the Penguin skittles project. Carefully measure the maximum width of the ball, and create a cylinder just slightly larger in diameter. Mount the cylinder in the lathe, bring up the tailstock and mark the width of the ball. I noticed a small flaw in the end of the cylinder, hence my marking it well in from the end
2. Part down either end. You can see that I added 5⁄64in (2mm) or so at either end to allow for clean-up later. If you mark everything exactly, it removes your margin for error. Mark the centre. Divide each half in two, and mark those positions
3. Using the spindle gouge, partially turn the outer quadrants so that you have a flat on them. Don’t make these too steep, or you will remove some of the wood you wish to keep
4. Start to refine the shape, working on either side from the top down to the parting cuts. Then, part or cut off the partially shaped sphere
5. Fix the sphere between two friction drives purpose-made to hold spheres, mounting it so that the square ends are vertical. Refine the shape. Note the square end – it is quite large and the sphere shape is not quite right. This shows my mistake. While the length of the sphere was right, and I got to the correct sphere diameter from this, I forgot to adjust the width to match the length. To correct this, I had to make extra cuts all the way round to get to the right diameter
6. Remember to turn the ball frequently, so that you get a nice even form. If you are micro-adjusting the form, an angled scraper or skew chisel laid on its side in scraping mode will work well
7. Once shaped, sand the sphere all over and check for fit in the cup you have already created. Can you see here how it sits a little high? If this happens, remount the sphere and adjust until it sits neatly in the hollow

Making the false cap

1. Take the cylinder of wood that contains the lid, and mount the tailstock end in your chuck. Cut a spigot to suit your chuck jaws, in a position that leaves a section longer than is required for the finished lid. Part off the lid, leaving the spigot on that part
2. The section remaining in the chuck will be used for the false cap. This form must sit over the loose ball while its upper surface mimics a hollow half-ball. When the cup is placed against the cylinder, the false cap is slightly wider than the maximum width of the top of the cup
3. Measure the outer diameter of the spigot on the cup, and transfer this onto the tailstock end of the false cap. This marks the outer edges of the recess needed to join the cap onto the top of the cup
4. Hollow out the bulk of the inside hollow, but stop about 1⁄4in (6mm) short of the marked recess width
5. Use a skew chisel on its side to create the recess to width and depth. Refine the inside of the hollow, check that the ball fits snugly but can be easily removed. Fit the ball in the cup and bring up the cup and ball to fit against the false cap, to double-check everything. Any errors at this stage are hard to alter later
6. You need to have as thin a wall thickness on the false cap as possible, but avoid breaking through the square lower corner of the recess. You also need to mimic the shape and size of the loose ball as closely as possible, without making the wall so thin as to be fragile. If shape and size wrong, people will quickly spot the difference between the false cap and the ball. The thin parting tool will help make a fine cut to depth
7. Use the spindle gouge to refine the exterior shape of the dome
8. When close to the final shape, use a scraper for your fine adjustments. Delicate, light cuts will help you to achieve a nice, clean finish that requires minimal sanding
9. Place the cup up against the false cap. You already know the loose ball fits; now check that everything looks right
10. Make adjustments to the false cap as required
11. Cut off the false cap through the waste section, and use the waste section to create a jam chuck with a spigot on the end to lock into the recess in the false cap. Clean up the top, using the spindle gouge to deal with the small pip of wood. Sand it

Finishing off

1. Mount the lid in the chuck. Measure the width of the largest outer diameter of the sphere cut on the false cap, and transfer this diameter to the underside of the lid
2. Remove the bulk of the waste with the spindle gouge, using the same end-grain hollowing technique as before. Refine the inside with a scraper but stop shy of the maximum width required
3. Regularly place the false cap into the hollow to check for a good fit. You need to be able to lift off the lid with one hand without touching the false cap. Sand the inside of the hollow
4. Remove the lid from the chuck and fit the cup in place. Place the false cap on to the cup, then the lid on top of this, and bring up the tailstock. Using the spindle gouge, refine the outer shape to get the curvature and width of the pieces flowing together
5. Use the bead forming tool – or if you are cutting the outer detail by hand, a tool that will allow you to do that – to form the beads as far as you can on the plain sections exposed. Pay particular attention to the joins. Make sure that you get clean cuts, with the grooved lower sections of the beads right on the joins. Don’t leave any steps or scores in areas that will be visible
6. Use the spindle gouge to refine the very top of the lid. Again, use a bead forming tool to create beads, staying just shy of parting through at the top of the bead. Stop the lathe and remove the waste with a carving tool. Sand the top of the bead
7. Now you need to finish off the cup. First, cut more beads
Tip

V cuts, stepped pyramid-like details or beads work very well to disguise the joins in this project, but the wall thickness needs to allow for this. Also, make sure that each detail has uniform width, spacing and depth, so that you cannot see any irregularities. 

8. Then, refine the base part of the cup, and bead that area before sanding and parting it off
9. Colour the parts. I dyed all the surfaces black, except for the ball and the outer dome of the false cap. Black disguises joins well. I used red for the ball and for the part of the cap that masquerades as the ball, because this stands out well against the black. Once dry, I coated the dye with a satin lacquer
10. It is worth noting that on the false cap, I did not replicate exactly the raised spigot section seen on the cup in which the ball sits. Some of the older versions of this trick do have it, some do not. You can copy this detail and have a perfect match, but most people won’t notice this slight discrepancy
The assembled trick

The trick

Start the trick with all the pieces in place. Then, pick up the lid and the false cap as one unit. Do not separate the two parts; keep them tight in one hand. You have revealed the loose ball in the cup. Now, remove the ball and place it in your pocket. Replace the lid and false cap on top of the empty cup. After a little theatrical ‘business’ and a few magic words, lift only the lid, leaving the false cap in place to suggest that the ball has magically returned.

The surprise should be sufficient to dupe most victims, although the success of the trick will depend on both your conjuring and turning skills!

Book details

Turned Toys
ISBN: 9781784940652
RRP: £16.99

Click here for more information

Further reading

A Brief History of Woodturning

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