Which of the following measuring tools is not typically used for precise linear measurements?

C-clamps are designed primarily for holding materials securely in place rather than for making precise linear measurements. They are widely used in woodworking and metalworking to grip workpieces during assembly or cutting, ensuring stability and preventing movement.

In contrast, calipers, thickness gauges, and depth gauges are specifically designed for accurate measurements. Calipers can measure internal and external dimensions as well as depths with a high degree of precision. Thickness gauges are utilized to measure the thickness of materials, ensuring that they fit specific requirements. Depth gauges are instrumental in measuring the depth of holes or grooves, further highlighting their role in precise measurement tasks.

Therefore, while calipers, thickness gauges, and depth gauges are calibrated tools meant for precision, C-clamps serve a different purpose, emphasizing their role in holding rather than measuring.