If the sharpener pic was a little closer and more in focus and taken from a another angle it would helped to figure out exactly how to design it. I've looked online for other pictures, but they were out of their packaging and too far away and if up close they were in their packaging.

In the photo it's difficult to say what the exact dims are of any part of it. I inferred everything from knowing the OD of the airframe tubing and gave it my best shot.

I'd love to hold it in my hands and actually measure it and get some good photos of it.