A sintered compact for use in a machining tool comprising 80 to 10 volume % of a high pressure form of boron nitride, and the balance a matrix of at least one binder compound material selected from the group consisting of a carbide, nitride, carbonitride, boride or silicide of IVa and Va transition metal of the periodic table, their mixtures as well as the solid solution of these compounds; the matrix forming a continuous bonding structure in the sintered body.A method of producing the compact comprises preparing a mix of 80 to 10 volume % of a high pressure form of a boron nitride powder with 20 to 90 volume % of at least one powdered binder compound selected from the group consisting of a carbide, a nitride, a carbonitride, a boride and a silicide of a IVa, or a Va metal, mixtures thereof or solid solutions of these compounds, and sintering the mix under pressures more than 20 Kb at temperatures higher than 700.degree. C. for more than 3 minutes.