Facing machine for preventing inflow of cutting chips into tube

A tube-facing machine, comprising:

• a driving unit comprising a driving shaft and a housing, the driving shaft comprising a first shaft having a rear end connected to a motor and a front end formed in a polygonal shape and a second shaft having a rear end having a recess formed therein in a shape corresponding to the front end of the first shaft so as to be axially connected to the first shaft and a middle portion having a small diameter to have an adjustment recess formed therein, and the housing accommodating the rear end of the first shaft and the motor;
• a cutting unit comprising a cutting tip mounted to a front end of the second shaft;
• a tube-mounting unit formed in a pipe shape, wherein the tube-mounting unit is connected to a front portion of the housing to accommodate the cutting unit, and wherein the tube-mounting unit allows a tube to be cut to be mounted in a front end portion thereof so as to be concentric therewith;
• and
• an adjustment unit comprising:
• a bearing inserted into the adjustment recess and having a moving protrusion formed to extend outwards, wherein the moving protrusion is configured to move the second shaft forwards or backwards upon application of external force;
• and
• a return spring configured to return backwards the moving protrusion and the second shaft that have been moved forwards by external force.