Zinnia Kinetic Sculpture

In an effort to understand kinetic motion drive mechanisms, I purchased a Clayton Boyer plan titled “Zinnia”.  Dr. Boyer sells plans in two formats, DXF files for CNC machines or paper plans that can be cut on a scroll saw.  I built Clayton’s Number 6 clock a few years ago and it works very well, keeping almost perfect time.  I cut my Number 6 using a scroll saw but now that I have a CNC router, I cut Zinnia on that machine.  The DXF files needed a little CAD work prior to generating tool paths because some of the vectors were open.  This is nothing that any decent CAD program can’t handle so not to worry.  Anyone interested in Clayton’s plans, check out his website lisaboyer.com/Claytonsite/Claytonsite1.htm.

Zinnia is a kinetic sculpture that is spring driven on a single shaft that has two counter-rotating sculptures that deliver a visual moire effect. The wheels are 24″ in diameter which tax the limit of my CNC machine table.  The following photos should be of interest to people considering making a kinetic sculpture.

Small Parts

Small parts were nested based on thickness. The plans called for three different thicknesses, half, quarter and eighth inch.

Cutting the Large Wheel

The large wheels were cut from half inch thick Baltic Birch plywood using an eighth inch two flute end mill. I get good results using a speed of 32 ipm with a plunge rate of 20 ipm at 20K RPM. I used the CNC to make alignment holes, click holes and counter-bores for the bearings prior to the final profile cut. I stained the facing side prior to cutting because it was easier staining a large flat panel than staining a delicate, intricate part. A little touch-up with marking pens took care of chipping.

Screen Shot

A view of the Mach3 screen as the wheel was being cut.

Cut Nearly Complete

Here is a look at the part as the final cut is nearing completion. At my feeds and speeds, the part took about 1 hour and 20 minutes from start to finish.

Cutting the Tabs

The part is held in place using tabs connected to the waste as the cut is being made. When finished, the tabs are cut using a chisel and then cleaned up by hand sanding. This operation took longer than the CNC machine took to cut the part.

Completed Wheel

The shape of a flywheel after separating it from the waste. The sculpture is destined to be mounted on a light colored wall so the wheels were stained black.

Zinnia Mount

Fast forward to when all the parts were cut out and finished. The wall mount with the stud is shown in the photo.

Rear Wheel

Next in the stack is the rear wheel.

Motor Drive

Next comes the spring driven motor drive.

Front Wheel

The final part of the sculpture is the front wheel and cap.

 

Zinnia Displayed

Click on this picture to see a YouTube video of Zinnia in action.