Abstract: A cylindrical bore of a head member with a coaxial sleeve portion has at one axial end a larger-diameter part, the diameter of which is somewhat larger than the diameter of a cylindrical shaft which is to be press-fitted into the other end of the bore to achieve secure attachment. The large-diameter part ensures that a wear-resistant but fragile tape contact shoe (such as, a shoe made of ceramics) intimately surrounding the sleeve portion of the head member opposite the larger-diameter part will not be cracked or otherwise damaged when the cylindrical shaft is thrust into the cylindrical bore.