Odds and Ends
| Page Last Updated: 1 June 2007 |
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Jig
Bleriot wheel
Picture of first trial wheel and jig
Second trial
Third trial |
This is an improved method on the original, which gives a much better look to the tyre, if you look at the picture in the first method below you'll see what I mean. I made a jig, which cuts down the amount of work needed to build repeat wheels. Dimensions are chosen for 1/72nd scale. Larger scales will need changes to suit. The wheel in the picture was made with 0.052mm diameter monofilament nylon fishing hook tie line, this gives a 3.75mm diameter spoke for 1/72nd scale which looks good. Thicker line can be used for larger scales. I use brass rod for the axle, a piece about 4 inches long makes handling easier and allows plenty of room for slipping before the wheel comes off the end and you swear a lot. The jig is based on the method shown in Harry Woodman's book Scale Model Aircraft in Plastic Card - I recommend it. The first trial picture shows a wheel wound from hub to slot and straight back, this gives two spokes to each position on the rim - not realistic. The second trial is wound from the hub to a slot, on to the next slot, then back to the hub. Because every slot was used the spacing at the wheel rim is uneven. The third trial was wound as described below and as shown in the Jig drawing The jig was cut from thick plastic card, marked and slotted in 36 positions. A notch at the end of the slots makes it easier to wind. I marked the slots as well to make aligning across the hub easier. I chose 36 slots as this is the number of spokes on the wheel of the Bleriot I am building. Jig is 40mm across, the centre hole is 25mm. The wheel rims/tyres are made from plastic tube of the correct diameter. The end of the tube is shaped with a knife and paper, then a thin ring sawn off the end by rotating the tube against a razor saw blade. This ring is then sanded on the flat side till a half wheel is made. Repeat for the other half of the wheel. Keeping the sanded face rough helps to clamp the line when the wheel is assembled Cut a length of monofilament nylon line ( about 1.5m) and colour if desired using indelible marker pen. Tape the monofilament nylon line to the starting point on the jig. The winding pattern I used is arranged so that when the wheel halves are stuck together over the 'spokes' the spokes end up evenly spaced around the rim. One side is done, then the other, the spokes coloured red and blue in the Jig Drawing are on opposite sides of the wheel. Wind the line around the hub, taking the line to the slot next to the one opposite. Loop the line back through the next hole, and go across as before as the whole wheel is done the end in the line on each 'turn' will hold the hub in the centre. Take care not to make the line too taut otherwise the spokes are under too much tension when compressed between the wheel halves, and they can pull out when the jig is cut off. If done correctly you should end up on the first side with alternate pairs of slots used. Turn over and repeat the process, starting from one of the slots that is already used, so that one slot has two spokes and the next-but-one slot has none. Tape down the end of the line on the jig. Glue the two halves of the rim/tyre onto the spokes in the jig. Clamp tightly and leave to dry. If you find a good method of centring on the hub let me know please. Finally superglue the hub to the spokes to hold the wheel in position, and paint. I leave fixing the wheel to the hub till last as the ability to slide up and down the rod reduces the stress on the spokes during the build. When gluing the second side push the axle through a little to dish the wheel When dry cut out the wheel, and finish off. Simple! - it's certainly satisfying when it all works out |
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Dimensions and numbers are chosen for 1/72nd scale. Larger scales will need changes to suit, e.g. radius, no. of spokes. I use 0.125mm diameter monofilament nylon fishing hook tie line, this gives a 9mm diameter spoke for 1/72nd scale but it looks OK. Thinner line, 0.052 gives a spoke of 3.75mm, more spokes can be used on the wheel, but it does get a bit fiddly. I use brass rod for the hub, a piece about 4 inches long makes handling easier and allows plenty of room for slipping before the wheel comes off the end and you swear a lot. Mark 60thou card with 16 radii about a centre point, and roughen the surfaces with sandpaper. Drill a small hole on each radius to form a circle about 4mm from the rim of the wheel. Drill out the centre of the wheel, 8mm diameter. Cut out around the ring of holes to make a 'washer'. Cut a length of monofilament nylon line and colour if desired using indelible marker pen. Superglue monofilament nylon line to one radius. Wind the line around the hub, taking the line to the hole next to the one opposite, as the whole wheel is done the end in the line on each 'turn' will hold the hub in the centre. Take care to keep the line taut. I wind the whole wheel before supergluing the end 'turn' , but I suppose some could be fixed half-way through. Superglue the end 'turn' , and then all the turns by running a circle of glue around the flats of the 'washer'. File the washer to size, then build up the tyre. I used superglue/baking soda or filler, then sanded to shape. Steve Perrys' suggestion of sanding rings to make tyre halves would probably give a better finish, I just haven't tried that yet. Finally superglue the hub to the spokes to hold the wheel in position, and paint. I leave fixing the wheel to the hub till last as the ability to slide up and down the rod reduces the stress on the spokes during the filing/sanding. |
