The Mount


Making a 4.25 Inch Dobsonian Reflector Telescope




          The mount consists of three separate parts, the rocker box, the fork and the base.  





The Rocker Box


          The rocker box is just that, a box that rocks back and forth.   The box has two wooden circles screwed to the sides.   These circles were made with a router plus circle jig.   The size of the box is just big enough for the tube to slide through.




          My own modification to the box is to fit it with a screw with a large handle to tighten the tube.   This allows quick and easy balancing of the tube.    The screw will make small marks on the tube.   If you don't like this, it's possible to shield the tube with a thin piece of metal, which needs to be held onto the inside of the box somehow.    This screw also allows the scope to be shrunk down when transporting it.





The Fork





          The fork consists of three boards screwed into a round base.   The two side boards have V shaped cuts for the rocker board circles to fit into.   These V shaped cuts have Teflon strips glued to them to reduce friction.    Finding glue that will bind to Teflon is a bit of a tricky but it can be done.



The Base


          The base is a second circle of wood that fits below the fork.   These pictures describe show the first version which did not work out.  The problem was that the base was not large enough, and the scope tended to tip over.   I replaced the base with a large circle which solved this problem.



The base has three short legs.  These have two functions.  They provide stability on uneven ground, and they are needed to allow the central bolt to clear the ground.   The bottom of the fork has three furniture Tephlon pads screwed into it.




Between these unseen pads and the base is an old 331/3 vinyl LP record.   The three circles, the fork, the record and the base are held together with a very large locking bolt.