One of my wife's favorite books on colored pencil technique was Creating Radiant Flowers in Colored Pencil by Gary Greene. She learned about the technique of burnishing from that book.
We were surprised to learn that Gary actually lives just north of Seattle and that he was giving a class at Daniel Smith in South Seattle. We signed up. We took the Easels up with us and the man, himself was very interested. He really liked the ability to put a work at any angle and rotate it 360 degrees.
After the class we got a call and he wondered if we could make one for him. We visited him in his studio and spent several hours there. He wanted one in large format because his works are quite large. We built one that was almost 3 x 4 feet. It worked well but we had to fabricate a special tightening knob so he could reach it from around the board. It turned out pretty nice.
"This is a great tool. I wish I had thought of it.", he told us over hamburgers at lunch at Teddy's.
As we said, Gary's work is large and here are some examples. You can see more at Gary Greene Art on the web. The painting of the marbles on Mylar is about 32" wide. By the way, I have seen that work and it is not on black paper. It's done on white paper and the entire background is layer after layer of black colored pencil.
Thanks, Gary for your help and support.