Thank you for your comment, excuse my English is a Google translation I only did Spanish first language and industrial design second at the time!
We do with, so I actually used axes and old printer rollers and the aluminum profiles of my 3d printer I did not finalize the pen holder nor his movement I wanted to test the displacement on the threaded rod of 8 the cart carries a few worries in the middle of the axis speed must be too fast, I think I'll review this training and opted for a belt.
Initially I went on the idea of making a tracer to A2 by turning the sheet of course. It was a "style exercise" to use the profiles and engines in my possession. I will get back to work thanks to you!
I will keep abreast of the evolution thanks again and have a good day.