The chain ring (sprocket) is cut from the carbon fiber. I used a 1/16 diameter", (2) flute, spiral upcut, solid carbide end mill. You could use a larger diameter end mill because the smallest inside radius in the design is 0.156". The material cuts easily in a single pass at about 40-50 inches per minute. I have heard carbon fiber can be cut on high power lasers (100’s of watts), but you should not try this on lower power hobby lasers.
The dust is messy and probably dangerous to breathe, so keep a vacuum on at all times and use a mask and eye protection.
The dxf file has the outline. It also has some construction lines on layers you can turn off. The chain ring is actually a geometrically accurate sprocket. If you want to make your own size or just like to geek out on this stuff like this (like I do), see the final step.
The cut edge quality was quit high as you can see from the second image.
I had as much fun learning about chain rings as cutting the parts. If you want to make your own geometrically accurate chain ring, follow these instructions.
You will need (3) parameters.
I wanted a clock that is about 6.5 inches in diameter. You calculate the diameter with this formula.
Pitch Diameter = Pitch ÷ sin (180° ÷ ToothCount)
It turns out, 40 teeth gets me pretty close.
I used Draftsight, a free AutoCAD clone, to draw my part because it is easy to draw accurate angles and offsets. Here is the process: