tubing and push this into the hole drilled in the drive shaft block, leaving equal amounts of tubing protruding from each end. File the ends of the tube smooth.
9: Drill a .125 in. (3 mm) hole in the outer edge of the large flange washer for the connecting rod attachment. Place the threaded rod through the brass tube and assemble the washers and nuts, large flange washer, and lock nut, as shown. Don’t overtighten. Test that the shaft rotates freely.
10: Drill a .3125 in. (8 mm) diameter hole through the center of the pivot block and push the remainder of the brass tubing into the hole to check that it fits.
11: Now screw and glue the two blocks to the platform in the positions shown above. In order to reduce friction in the pivot block when it is mounted, position a round-headed screw in the underside of the platform, as shown above, before attaching the pivot block.
12: Glue and nail the figure to the platform in the position indicated. Screw the small eye into the back of the figure at the point shown in the picture for step 3, and then cut and bend the connecting rod wire, using the dimensions given as a guide only. Adjust as necessary. Put the small bead in place; this keeps the connecting rod clear of the end of the drive shaft. Attach the connecting rod to the flange washer and to the figure.
13: Test the movements of the drive shaft and figure and adjust the length of the connecting rod as necessary.
14: Make a deep V-shaped groove in the top of the chopping block and place it in position, without using glue, on the platform. Next, temporarily attach the axe between the figure’s hands. Rotate the drive shaft and test the movement of the axe in relation to the chopping block. The axe should go partway into the groove without actually touching it. Adjust the positions of axe and block as necessary and then glue and pin them into place.
15: Make the four-bladed propeller as shown. The correct shape and size of the hub, propeller blades, and other details can be worked out from the templates.
16: It is easiest to drill the holes while the hub is still square. Carefully mark and drill right through the wood the .3125 in. (8 mm) diameter center hole, and then mark and drill to a depth of .75 in. (19 mm) the .5 in. (12 mm) diameter propeller arm holes. Either cut the hub to shape or leave it square.
17: After checking that the arm dowels fit in the holes drilled in the hub, cut the arm dowels halfway through, as shown. The flat surfaces formed by this shaping accommodate the propeller blades. The lower edges of the blades should not be closer than 3 in. (76 mm) to the hub center.
18: Glue the individual blades into position and secure them with small panel pins, taking care not to split the dowels (see Tools & Techniques chapter for advice). Allow the glue to dry before going on to the next step.
19: Insert the arms into their respective holes in the hub, without using glue. Rotate the arms so that pairs of blades are at opposite angles of about 45˚ to each other on either side of the hub. Glue the arms into position. Test the propeller for balance, using a spare piece of rod or a suitably sized nail as a free pivot. If one blade is heavier, it will always come to rest at the bottom. Remove surplus wood from the blades until the balance is correct. Then fit the propeller to the drive shaft and secure it with the nut and lock nut.
20: Fit, glue, and nail the tail into the tail slot already cut in the platform. The tail piece helps to keep the propeller facing into the wind. When the glue is dry, test the mechanism outside in the wind. It may be necessary to make minor adjustments to ensure smooth running.
21: If the whirligig is to be used outdoors, you must protect it with good-quality oil-based paint over a sound undercoat. You could choose a realistic color scheme, or go for brighter, more whimsical shades. Make sure no paint is allowed to clog the working parts.
22: When the paint is dry, mount the whirligig on a suitable pivot, such as a steel rod or a nail driven into a stand or post.
23: The drive mechanism of the whirligig will need a drop of oil from time to time to ensure that it continues to work smoothly; applying a light grease (petroleum jelly) to the drive shaft before assembly is a useful long-term precaution.
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