Tungsten carbide tips designed for use on man-made timber that blunts ordinary Forstner bits quickly. Two most popular sizes to fit concealed hinges in kitchens/bedrooms etc. Suitable for hard and soft woods, veneered and laminated boards. Tungsten carbide tips designed for use on man-made timber that blunts ordinary Forstner bits quickly. Two most popular sizes to fit concealed hinges in kitchens/bedrooms etc. Suitable for hard and soft woods, veneered and laminated boards.