Abstract: There is provided a process for preparing a 5-amino-1,2,3-thiadiazole represented by the formula ##STR1## wherein R represents a hydrogen atom, a lower alkyl group or an aryl group, which comprises bringing a diazoacetonitrile represented by the formula ##STR2## wherein R has the same meaning as defined above, into contact with hydrogen sulfide in the presence of a base or with a salt of hydrogen sulfide, in a solvent.

Abstract: A polygonal throw away insert includes an insert body having two opposite, parallel major surfaces and a plurality of sides. A cutting edge is formed along a line where each of the sides joins each of the surfaces. A ramp extends from each cutting edge downwardly towards the center of at least one of the two major surfaces of the insert body. A pair of first chip breaking projections are provided on the ramp adjacent each corner of the insert body in a symmetrical relationship with respect to the bisector of the corner, and a second chip breaking projection is provided on the bisector behind the first projections.