A surgical bur including a shaft with a head on the distal end of the shaft. A number of flutes extend outwardly from the head, each flute having a rake surface and a clearance surface. On some flutes the rake and clearance surfaces meet to form the flute cutting edges. Other flutes have relief surfaces between the rake and cutting surfaces. On these flutes, the cutting edges are the edges where the rake and relief surfaces meet. The flutes are further designed to have rake angles that are less negative, than the flutes without the relief surfaces. The flutes are radially spaced apart around the head such that between any three adjacent flutes, the first and second flutes are spaced apart a first angle the second and third flutes are spaced apart a second angle different from the first angle.
