English to Portuguese Tech/Engineering Engineering: Industrial

Sabemos que broaching machine é brochadeira (ou brocheadeira). O que seria uma turn-turn broaching machine?

- brochadeira de giro-giro
- brochadeira de duplo giro
- brochadeira de dupla rotação

?

Mesmo em inglês a dobradinha turn-turn é estranha (veio do alemão Dreh-Dreh). Agradeço imensamente quem me der uma pista. Aqui contextos:

Komatsu produces many machines for the manufacture of internal combustion engines including camshaft millers, roller burnishing machines and turn-turn broaching machines. A new milling-centering machine has been developed and top of the range is a complex machining center capable of fi ve face complex machining and slanted complex machining in one chucking. Komatsu also manufactures high precision machines for semiconductor manufacturing equipment and production of flat screen displays (LCDs).

http://www.industry.siemens.com/topics/global/en/magazines/s...


A production line for carrying out machining steps from a forged crankshaft starting material to a semi-finishing machining step of the pins P1 to P4 is normally configured from a total of six machining tools comprising, as shown in FIG. 21, a centering machine M1, a front-side lathe M2, a rear-side lathe M3, and a first crankshaft mirror (pin mirror) M4, a turn-turn broaching tool M5 and a second crankshaft mirror (pin mirror) M6 of a shaft machining device, the crankshaft S being manufactured to a predetermined shape as a result of a crankshaft starting material S′ being successively introduced into and machined by the machine tools M1 to M6.

http://www.google.com.vc/patents/US7424776