theseatonslicer:
Writing goes face up so when you close the tacho it makes contact with the scribes.
On the cassette tacho, make sure you get the chart underthe 2 teeth at the top or it will chew the tacho to pieces! I know this through experience!
I lent you a couple of image tags to illustrate your post, Hope you don’t mind 
Has anyone got a pop up toaster from a Volvo?