Under Pressure

This issue, Alex Bishop deals with the twin troubles of tension and playability that you may encounter when building a guitar

I made the surprising realisation this week that there are no less than 18 projects currently underway in my workshop. Among various repair and restoration jobs in progress were my current builds, my students’ guitars and a half-abandoned electric guitar that I started building for myself (which inevitably ends up taking a back seat in lieu of more important work). I welcome the diversity of the jobs, but this month one subject just kept cropping up: tension.

It started when one of my guitar-making students asked me why two of his classical guitars appear to have different amounts of tension in the strings, and it got us into discussing the factors that affect string tension, how to calculate it, and what else might be at play. Fundamentally, there are only three factors involved here: the material and thickness of the strings, the tuning, and the scale length of the instrument.