Abstract: A grinding tool comprises an endless abrasive belt looped around a drive pulley 2 and an idler pulley 23 and straddling therebetween a first arm 6 and a second arm 18. Tension is maintained in the belt by biasing element 10 acting on an end of the first arm. The first arm 6 is mounted in a slide assembly 4 which includes elements 5,7,8 for preventing the arm from sliding back into the assembly in use. The second arm 18 is pivotally mounted in a tracking head assembly 14 on an end of the first arm 6, with lateral biasing elements 16, 17 acting on respective opposing sides of the end portion of the second arm 18. This permits tilting of the idler pulley 23 to obtain correct tracking of the belt, and enables the arm 18 and the belt to be rapidly and easily changed.