Since　the　cathodes　with　machined　surfaces　are　required　for　the　practical　applications　in　some　high-power　vacuum　electron　devices,　the　characteristics　of　nanosized-scandia-doped　dispenser　(SDD)　cathodes　with　machined　surfaces　have　been　investigated,　especially　in　dc　applications.　In　order　to　reopen　the　surface　pores,　which　may　be　smeared　by　machining　procedure,　the　cathode　surface　was　washed　by　Ethylene　Diamine　Tetraacetic　Acid　(EDTA)　solution　and　prolonged　time　was　taken　for　the　cathode　activation.　The　emission　test　results　show　that　the　SDD　cathodes　with　machined　surfaces　exhibit　better　emission　performances　after　treatment.　The　space-charge-limited　dc　emission　current　density　of　over　20　A/cm(2)　at　900　degrees　C-b　has　been　measured　with　temperature　compensation　for　electron　cooling　after　full　activation.　An　on-going　life　test　with　a　dc　load　of　up　to　40　A/cm(2)　at　970　degrees　C-b　has　been　completed　similar　to　5000　h　of　operation　to　date.　Since　the　emission　capability　can　be　fully　restored　after　exposing　to　air　and　reactivating　for　a　short　time,　a　preheating　procedure　is　favorable　for　SDD　cathode　with　machined　surface　in　the　practical　applications.　Surface　analysis　indicates　that　a　recrystallization　of　tungsten　grains　occurs　during　the　prolonged　heating　process,　leading　to　further　reopening　of　the　surface　pores.　As　a　result,　cathode　surface　is　covered　uniformly　by　active　elements　of　Ba　and　Sc　(as　well　as　O)　as　on　an　unmachined　surface,　thereby　maintaining　the　high　emission　property　of　the　SDD　cathode.