Tom qab kev teeb tsa, thaj tsam kam rau ntawm lub qhov threaded yog nyob ntawm qhov kev kam rau siab ntawm cov xov hlau ntxig profile thiab cov xov tolerance tsam ntawm lub qhov mounting. Cov qub yog tswj los ntawm cov xov hlau ntxig cov chaw tsim khoom, thaum lub sijhawm tom kawg yog nyob ntawm qhov tseeb tapping ntawm lub qhov mounting, feem ntau tsim 6H qib kam rau ua, uas tuaj yeem ncav cuag 5H lossis 4H qib rau siab dua. Cov txheej txheem sib koom ua ke yog 2B lossis 3B.
Cov qib sib txuas ntsuas ntsuas tuaj yeem siv los tshuaj xyuas cov xov hauv qhov kev tsav tsheb.