Support for 2 centesimal comparators (body dia 52 mm) for BF20

thingiverse

Support for 2 centesimal comparators (body dia 52 mm) for BF20 milling machine. Projects of supports of this type, more or less detailed and well made, can be found both online and on the same thingiverse platform but this has been specifically designed to adjust, as precisely as possible, the head of the BF20 milling machine (or various clones). In addition to the two comparators, the support also houses a bubble level to check that the machine has been correctly leveled. The zeroing of the instruments must be carried out on the same point, aligning the support with the Y axis. It starts by bringing the rotating dial of the first comparator to zero and then, rotating the support by 180 degrees, the second one will be brought to zero. For this delicate operation it is a good idea to place a small reference block between the comparator rod and the base of the cross table. Once the calibration has been carried out, the reset must not be touched anymore! To check the exact verticality of the head, rotate the support by 90 degrees, aligning it with the X axis, and then lower the column making sure that both comparators go correctly for reading, with the needle of one of them positioned exactly on zero. The perfect verticality of the head is obtained when both comparators measure the same value. With the same system, taking into account that in any triangle the relationship between the measurement of one side and the sine of the opposite angle is constant, you can adjust the head perfectly to the desired angle. For this purpose, keep in mind that the distance between the tips of the comparators is 102 mm and that the distance between the comparator that moves upwards and the table must be compensated by interposing a listed object. The shaft connecting the support with the ER collet or with the spindle must be made on the lathe, as precisely as possible and using at least one C40 steel. Needless to say, the two screws (knobs in the photo) are used to hold the instruments firmly and therefore must not be tightened excessively. The object has been printed in PLA and works perfectly but perhaps ABS or PETG would be more suitable for this project.