| 摘要 |
A bur for use with a machine comprises a head and a shank that are made of dissimilar materials with a joint between the head and the shank. The material of the head has a lower coefficient of thermal expansion than the material of the shank. The shank has a recess in one end. The head has a working surface and a projecting portion that cooperates with the recess. The joint is formed at an interface between the projecting portion and the recess whereby a portion of the head that includes the projecting portion is compressively stressed. The projecting portion may have a cone-like shape and the recess may have a cup-like shape. The material of the shank may be stainless steel and the material of the head may comprise metal carbide. The bur may be a dental bur. |
