If this lathe is unmodified, it is a chinese clone with bad spindle bearings. You must replace the spindle bearing with "Tapered Roller" bearings, also fix the carriage GIB and replace the weak DC motor. Chinese lathe is a Kit-Set, must be modified :)
OTU KATAI OMOTAI ANTEISHITA SAGYOU TABLE NI NOSETE SAGYOU SHIMASHOU UGOKASUTO SHIDOUDE KIKENDESU BAKANI DEKIMASENYO ANZEN NO TAME JIKAI WA TABLE SAGASHIDE WA DOUDESUKA?