One Day Builds: Kinetic Necklace Update

       This is somewhat of a follow up without an original so bear with me. I started making kinetic jewelry around 2012 after being unable to find any satisfactory steampunk jewelry. Everything I found was just plastic gears or old watch cogs glued onto some sort of base. As en engineer, I couldn't stand it. I have always enjoyed the work artists like Chris Fitch, Arthur Ganson, and Theo Jansen; for me, if art has gears they have to move.

The updated, machined necklace (not when I was 12)

       This was when I was 16. I had no experience with gear design, no machining or jewelry experience, and I decided I would have to make what I wanted. I used Matthias Wandel's Free Online Gear Generator to generate the involute patterns to which I added spokes to by hand. Frames and bridges were all drafted by hand. Using a my grandfather's old files and improvised tools, I cut the gears and frames out of unfolded copper water pipe and riveted the parts together with recycled building wire.   

       I only made 5 or 6 pieces, only one of which has left my possession. Looking at them again they are far less precise that I remembered them, but this combined with their recycled nature gave them a certain style. 

       How does this relate to a one day build? Fast forward 4 years and I chose to make a few more, and this time all out on the technology. The involute gears I used before would jam frequently due to low their low precision, even with a very high pressure angle. The high pressure angle also resulted in pointy teeth. I designed a totally different type of gears for the new pieces, based on a ring of evenly spaced semicircles. Alternating semicircles would be peaks and valleys of the gear. These are not suitable for power transmission but mesh very smoothly and are do not pinch or poke in any way. They also can be machined easily. 

The design of the new gears in 2D CAD

       This post really contains two one day builds. The first was the machining of the original necklace. The four pieces were machined on a Tormach and programmed with Fusion360. As much as I criticise the small Tormach mills, they do get the job done for small, slow jobs. I avoid our's when possible but if its the only machine open, you make do. I had intended to make a post about machining the components at the time but I never got around to it. The final piece measures only 20mm wide and is made out of 7075 aluminium and 932 bronze.

       Finally to the actual title of the post, the update. The client this was made for enjoys fiddling with necklaces, well suited for my work. I unfortunately underestimated just how much they would twirl the gears and the loctite joints holding the cage together came loose. Thrice. I decided to drill out the integral pins and use thread to stitch the cage together. I had originally intended to drill the pins and use them as integral rivets, but didn't have the proper tools at the time. 

Indicating the integral pins. 2mm dia. 1mm tall stepped to 1.5mm dia. 0.5mm tall

1mm drill 

       While I had the necklace I cleaned up some of the corrosion and took some better photographs. Speaking to this design and project overall, I am very please with the result. The scale especially makes it attractive, but it also means I probably wont make pieces this small again. If I did this again in the same or similar size, I would use a more durable material for the cage and use a more permanent connection.