DESCRIPTION
Past with strokes 1/3 center over center ( shortened: COC = “C. o. c.” ) is the classical stroke, the most widely used because it can be applied in all stages of processing both with the mirror above and below the tool, than vice versa.
The position of the hands is the one with the palm which rests and pushes from the edge to “hour 8:20” and with the thumbs pointing towards the center to apply pressure , while the fingers “hour 10:10” exert traction , always by edge .
In mirror mode above, with tool and mirror of equal diameter latter must be pushed forward and backward with the pressure ( light or in some more substantial cases, ) located in the center.
During the back and forth motion the center of the mirror describes a straight line segment that passes through the tool center, whose extension is 1/3 the diameter of the mirror itself. Then, The swiveling out longitudinal relative to the tool is 1/6 the diameter in the forward movement and 1/6 the diameter in the return movement.
The operator performs the forward and backward strokes and simultaneously performs a slow and constant rotation around the tool. After some past ( from 5 until 10 ) it makes a rotation of the mirror of an arbitrary value ( on average 30- 40 degrees ) in the direction opposite to that operator.
Among all the past is the one that most approximates the surfaces in contact with the spherical shape.
Fig.1 – of past schema 1/3 COC
STROKE SETTINGS AND ENFORCEMENT 1/3 CENTER OVER CENTER
- Position: mirror above with possibility of alternating mirror and the tool above / below
- Pressure: normally weak and localized at the center,
- excursion: on passing rectilinear trajectory for the mirror centers and tool up to 1/3 the diameter
- racing Number: from 5 until 10 before the rotation of the mirror ( or if the tool in the upper position )
- times : circa 2 seconds between 'return stroke, time-to-dried 2-5 minutes (dependent on the stage and the abrasive mixture used.)
- Path: During the races the operator moves around the tool according to a slow and steady rotary motion and rotating the mirror ( 30-40 degrees ) in the opposite direction each 5-10 Corsica.
- Grane used: all
- Effectiveness: good
- Form produced: spherical
- Precautions: –