نمایش نتیجه 1 تا 2 از 2 نتیجه یافت شده برای square drill collar:
n: a special drill collar, square but with rounded edges, used to control the straightness or direction of the bole;often part of a packed-bole assembly.
n: The drill collar that outside are square and inner are round.
n: A kind of packed hole assembly, which is consists of joining full diameter round collar above drill bit,then joining with square drill collar.
© ۱۳۹۲-۱۳۹۷ این اثر شامل قانون حمایت از مولفین بوده و هرگونه کپی برداری از آن ممنوع است.
