Proven to be one of the handiest tools for getting at those hard-to-reach spots in armature and stator slots. These special extra long and extremely hard tungsten carbide cutting tools cut right through and remove flash welds and other hard obstructions easily. These tungsten carbide burs perform best at higher speeds in the 18000 - 25000 rpm range. - Martindale carbide rotary burs are the answer for each tool is ground from solid tungsten carbide by precision automatic machinery assuring exact contours and dimensions as well as perfect concentricity.