A scratch strain gauge has an annular target removably supported on a first plate, which is fixed to a first area of a structure that is to have its strains recorded. The target, which has a groove in its periphery, is driven by flat springs, supported on a second plate, which is fixed to a second area of the structure and longitudinally spaced from the first area. The plates have an interlocking relationship for temperature compensation. A dust seal cover is disposed over the space between the plates and the target. A door is pivotally mounted on the cover and closes an opening formed between the cover and the first plate and through which the target can be inserted and removed. One of the supports for supporting the target is mounted on the door and engages the bottom of the groove. A resiliently mounted support on the first plate also engages the bottom of the groove as does a third support fixed to the first plate. The opening of the door enables the target to be easily removed. Reverse rotation of the target is prevented by a pair of resiliently biased elements engaging the periphery of the target. The driving of the target by the flat springs can be increased or decreased through lever arrangements. A scratch arm, which indicates strains of opposite senses on the target, is supported on the second plate and can have varying amounts of motion.
