1. Field of the Invention
The present invention relates to a cutter, particularly, it relates to a cutter used when cutting such as stones.
2. Description of the Prior Art
FIG. 4 is a plan view showing an example of a conventional cutter which is a background of the present invention, and FIG. 5 is a sectional view taken along the line V--V of the cutter shown in FIG. 4 The cutter 1 comprises a ring-shaped base plate 2. On the peripheral edge of the base plate 2, there are formed a plurality of projections 4 interposing slits therebetween. Furthermore, around the projections 4 of the peripheral edge of the base plate 2, a ring-shaped cutting body 5 is formed. The cutting body 5 is formed by sintering a metal powder including abrasive grains such as diamond particles. The cutting body 5 is formed such that a portion of slits 3 is exposed. The slits 3 serve to cool the cutter 1 with air when in use.
When using the cutter 1, it is placed against an object to be cut while rotating so that the object to be cut is cut by the cutting body 5. At this time, abrasions take place gradually on the cutting body 5 to expose its inner portion, thereby the sharpness of the cutter 1 is maintained.
In such a conventional cutter, however, if the thickness of the projections is made relatively thick, the projections hardly wear on use of the cutter As a result, the new inner portion of the cutting body is hindered by the projections to be exposed on the surface, thus degrading the cutter sharpness.
Also, since the mechanical strength of the cutting body formed at the slits is weak, there were incidences when the cutting body breaks at the slits.