As engineer’s straight edges are precision tools, they can be used to calibrate and check the accuracy of other tools. This means that you don’t always have to reach for the straight edge for tasks that don’t require the accuracy they provide.
Place the engineer’s straight edge on a bench or table with the working face facing upwards and a light behind it. Then place the edge of the tool you want to check up against the working face of the straight edge. If any light is visible between the two surfaces, then the edge of the tool you are checking is not straight.
This is particularly useful for checking the straightness of rulers and squares, as these tools can be used for accurately marking out with a scribe, knife or pencil instead of using your straight edge.
This will help to prevent damage and wear to the working face of your engineer’s straight edge, from running a scribe or knife blade along it.
If after checking your tool you discover it is not straight, it may be possible to straighten and repair it depending on the type of tool and what it is made of.
Checking fret heights
An engineer’s straight edge can also be used with a feeler gauge to check the fret heights on the neck of a guitar. If the fret heights on your guitar are not set correctly then this can cause what is known as ‘fret buzz’.
What is fret buzz?
Fret buzz is where one or more frets on a guitar neck sit higher than the others causing them to make contact with the strings when they are vibrated. This can have the effect of a small change in tone to a dampening of the note.