“If at first you don’t succeed, that’s normal” Colbert – Live Free Or Die
The Toy Jumping Jack is yet another project I’m building for my Home-Made Toys exhibit for the 2016 Newark Maker Faire. The arms and legs of this toy are pivoted on brads placed through the front and back of the torso. According to the instructions a heavy linen thread is tied at the pivot of each extremity, the opposite ends of the thread are tied to a ring below the torso. Pull the ring downward and “Jack jumps comically” says Mr. Hall, author of the instructions. Why isn’t life that simple?
For me, this project started right as rain. I collected a handful of thin pieces of poplar I saved from various projects and transferred the pattern for the torso, arms and legs. The pivot holes were drilled and the bandsaw was used to cut each part out. The tops of the arms and legs were painted and a strand of thick string was tied to each extremity. Four brads hold the front and back of the torso together and act as pivots for the extremities.
Drum roll please? I pulled the strings down and the arms and legs rotated skyward. Upon slackening the tension, only the legs returned down. The thick string jammed in the narrow shoulder clearance inside the torso. The thin wooden arms didn’t have weight necessary to enable gravity to do its job.
The first attempt to resolve the problem was to replace the thick thread with nylon coated stainless steel thread. The new thread was better but the arms were remained too light to function properly. All the original parts were discarded and I found thicker wood to cut new heavier parts. Initially these parts worked well with the steel thread but an unsightly tangle was created when I tried to neatly tie the four lines together.
More attempts to maximize the predictable animation of the jumping jack followed . The original thread performed best after fiddling around with how it attached to the limb and the location of the knot. Sometimes the task requires a touch more patience and attention than the originally put forth.
Jack’s head was carved from a scrap of basswood; the instructions suggest a wooden spool. This is mostly due to my abundant inventory of basswood scraps and the limited quantity of spools. The completed Jack was installed on the eight-blade windmill I constructed in an earlier post. Jack is so happy to be alive his limbs flail in the blowing wind like the excited customers in 1980’s Toyota commercials.