Some progress on the metal front. The rear reinforcement ring for the dew shield is done, as far as the turning is concerned.
First I skimmed the three aluminium discs on the lathe to make them flat and reduced the OD closer to the required size. Then I trepanned one of the discs and glued it onto another so that a can machine it distortion free.
The deep groove (2.5x2.5) in the middle is for a string of heating resistors. The shallow, angled groove is for engaging three spring loaded pins, when the dew shield is fully extended. There is also a 5mm wide undercut for a strip of self adhesive synthetic velvet, intended to prevent the scratching of the OTA when the shield is moved back and forth.
|