Rastrum
Tool with five parallel pens for drawing all five staff lines at once by hand.
What it means
The rastrum (from Latin rastrum, "rake") is a tool with five parallel pens that served to draw all five lines of a staff in one stroke. It consists of a handle to which the five drawing nibs are fixed at equal intervals. The scribe dipped it in ink and drew it across the paper along a ruler.
Musical use
Before ready-printed music paper existed, scribes and composers had to rule their staves themselves. The rastrum made it possible to draw even, straight lines quickly; the width of the lines and their spacing could be adjusted. Some composers, copyists and engravers used it into the 19th century. Manuscripts often show the fine traces of the rastrum.
The rastrum should be distinguished from music paper, the ready-ruled paper that later replaced it, and from music engraving, in which plates are engraved with notes.
Performance practice
If you want to rule a staff yourself, take a ruler and a rastrum and draw with an even stroke. Keep the pressure even so that all five lines become equally thick.