Machining　performance　of　boring　processes　is　often　limited　by　chatter　vibration　when　the　boring　bar　is　with　a　large　slenderness　ratio.　The　dynamic　vibration　absorber　(DVA)　is　the　most　widely　used　damper　in　practical　chatter　control　of　boring　bars.　The　DVA　consists　of　an　additional　mass-spring-damper　subsystem　and　needs　accurate　tuning　of　its　natural　frequency　and　damping　ratio　to　match　the　main　structure.　Compared　with　the　DVA,　the　friction　damper　consisting　of　a　mass　attached　to　the　boring　bar　through　a　sliding　interface　near　the　tool　insert　is　more　simple　and　easy　for　design　and　implementation.　The　main　purpose　of　this　paper　is　to　model　the　friction　damper　and　investigate　its　chatter　suppression　effect.　A　mathematical　model　is　established　to　depict　the　friction　force　at　the　friction　interface　between　the　damper　body　and　the　main　structure.　Based　on　the　modeling　of　the　fundamental　principle　of　the　friction,　the　dynamic　behavior　and　machining　stability　of　the　friction　damper　damped　boring　system　can　be　predicted　and　analyzed.　Parameter　studies　are　also　carried　out　using　the　numerical　model　to　evaluate　the　machining　stability　improvement　by　using　the　friction　damper　and　identify　the　best　configuration　to　maximize　the　boring　stability.