Back boring tool

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Back-facing is a calibrated facing process performed around a hole . This processing is carried out ” in shot”, i.e., the machine tool spindle moves away from the workpiece in the work step. The surface that is generated on the piece is generally used as a support for a washer, so that this has a flat contact surface. L’orthogonality of the lamination with the hole ensures maximum tightness of the screw acting on the washer. Not all back counter bores can be performed with the same strategy . In fact, it is necessary to choose the most suitable tool taking into account the relationship between the diameter of the hole and its length. For holes whose maximum length is three times the diameter (3xD) and whose counterbore is less than double the hole diameter, the eccentric back -hammer is used. On the other hand, when the counterbore exceeds the diameter of the hole by at least double or the length of the hole is greater than 3xD, the counterblades with interchangeable blade . ECCENTRIC RETROLLER This type of tool allows you to enter a hole from the front and perform a facing machining with a calibrated diameter on the opposite face of the piece.. The tool is single-edged and can be in solid hard metal or mechanically fixed. To use the eccentric back loom , the use of a numerically controlled machine is recommended. In fact, this allows to simplify the centering operations on the hole. As a preparatory step, you should orient the cutting edge to zero (spindle orientation = 0). At this point, the tool should be moved to the left by the measurement derived from the following formula: blade diameter minus hole diameter divided by two.