METHOD TO PRODUCE INTERNAL STRAIGHT CHANNEL IN LONG-LENGTH PIPE BY LATHE MACHINE Russian patent published in 2014 - IPC B23B35/00 

FIELD: machine building.

SUBSTANCE: at first a stopper is put into the pipe inside and a unit is installed so that to rest against it, the unit consists of a three-jaw self-aligning chuck fixed by the gaskets whose thickness is specified in advance which are set between the chuck jaws and the inner pipe surface so that its centre of rotation coincides with the centre of rotation of the pipe being bored, as well as of an internal bush with a plug guide hole into which a turning centre tip is inserted while the turning centre is installed in a stem pressed by the tailstock centre. The stem is fitted by a hollow mandrel with its length being less that the stem length which can travel along the stem longitudinally; one mandrel end is fitted by a fixture and is fixed in the machine tool holder, and the other is fitted by a fixture where a lathe tool is fixed. Afterwards boring of the pipe is started considering the optimal value of material removal, then after the tool fixture enters the pipe inside the mandrel is clamped in a turning steady rest and boring is continued until maximal permissible approach of the lathe tool fixture on the mandrel to the three-jaw self-aligning chuck set inside is reached. Then the process is stopped, the unit is demounted, the pipe is turned, the bored pipe side is clamped in the chuck, the stopper is put inside and the three-jaw self-aligning chuck is installed so that to rest against it while its jaws abut against the bored pipe surface without gasket being used, afterwards the bush with the plug guide hole is inserted in the chuck and the turning centre tip is set against it. Boring on the remaining pipe part is continued until connection with the previously bored part is reached.

EFFECT: expanded performances of a conventional lathe machine.

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