I made this 2d pen holder for my tevo tornado printer so that i can also use it as a 2d plotter or 2d printer. the linear rails has rubber bands on it so the pen insert force on the paper. the mounting holes of the sideplate to the linear rail can be adjusted in diffirent height. you need to lubricate both of the linear rails and pen mount to lessen the friction. also you need to put a rubber bands/loom bands on the holes to create a tension loaded pen slide mount. there is and adaptor that you can print to use 10mm dia pen.

the size of the holes in the linear rails are 3mm. you need to rebore the hole so the screws sa dig in the plastic.