Slide measure

The utility model relates to a measuring tool, particularly a vernier caliper. The utility model comprises a fixed ruler with a stationary jaw and a movable ruler with a movable jaw, wherein the slope angles alpha of the inclined surfaces on the end surfaces of the outer sides of the stationary jaw and the movable jaw are consistent with the slope angle of the inclined surface or the lead angle of the end part of the measured inner circle. In order to improve the measurement precision further, the utility model increases the length 'a' of the vertical surfaces on the end surfaces of the outer sides of the stationary jaw and the movable jaw. The structure of the stationary jaw and the movable jaw of the existing vernier caliper is improved in the utility model, the improved vernier caliper can more exactly measure the inside diameter of the circle of which the end part has the lead angle or the inclined surface. Because the slope angles of the inclined surfaces on the end surfaces of the outer sides of the stationary jaw and the movable jaw of the improved vernier caliper are consistent with the slope angle of the inclined surface or the lead angle of the end part of the measured inner circle, the mutual interference of both parts are avoided, an operator measures easily and conveniently, and the measured data is accurate. The overproof problem of the circular degree of products can be controlled effectively, and the process quality standard is satisfied.