Testing fixture for center holes

To solve the problem in the prior art that current testing fixtures are poor in testing efficiency and low in testing precision, the utility model provides a testing fixture for center holes, which comprises a base, a shaft sleeve, a testing rod, a spring and a standard block. The shaft sleeve and the base are in threaded connection with each other. The shaft sleeve and the center of the base are provided with coaxial through holes. The upper end of the shaft sleeve is fixedly provided with a dial gauge. The testing rod is arranged in the central through hole of the base. The top end of the testing rod is in contact with the testing head of the dial gauge. The lower end of the testing rod extends out of the base and is in the shape of a cone, wherein the lower end of the testing rod is matched with the center hole of a crank. The spring is sleeved onto the central part of the testing rod. The bottom surface of the base is vertical to the axis of the central through hole thereof and is served as a testing reference surface. The center of the testing reference surface of the standard block is provided with a taper hole. The depth and the conicity of the taper hole are the same with the depth and the conicity of the center hole of the crank respectively. The testing fixture for center holes is simple in structure and can be used for quickly and accurately testing whether a center hole is qualified or not. Therefore, the testing time is saved. The testing fixture has good practical value.