BORING MANDREL Russian patent published in 1996 - IPC

FIELD: metal working. SUBSTANCE: member for damping oscillation is made of a self-expanding material that changes its volume when it transits from one state to the other. These materials are bismuth, antimony, various alloys based on them, and so on. The longitudinal dummy opening in housing 1 is filled with bismuth. Air is removed from the opening with plug 5 that is screwed in the opening by way of a thread. Bismuth is increased in volume as it is solidified and provides stress in the mandrel. When openings are bored, the mandrel is set in rotation. Oscillation that occurs in working is damped due to dissipation of energy of oscillation owing to the friction between bismuth crystals and increased natural oscillation of the mandrel. EFFECT: improved design. 1 dwg