A downhole tool comprises a body having slots communicating the outside of the body with the body through-bore. A sleeve actuator and mandrel are selectively axially slidable. The actuator has flanges extending into the slots. The flanges have ribs on their sides that are inclined at an acute angle to...http://www.google.com/patents/US7252163?utm_source=gb-gplus-sharePatent US7252163 - Downhole under-reamer tool
