A sintered cubic boron nitride (cBN) compact for use in a tool is obtained by sintering a mixture of (i) cubic boron nitride, (ii) aluminum oxide, (iii) one or more refractory metal compounds, and (iv) aluminum and/or one or more non-oxide aluminum compounds. The sintered bodies may have sufficient strength and toughness to be used as a tool material in solid, i.e. not carbide supported, form, and may be useful in heavy machining of cast irons.