This weekend saw some progress on the Dobsonian project. I purchased 3/4-inch (19mm) B-B Grade 9-ply Hoop Pine in a 8'x4' sheet. This cost $130. I was going to buy the A-A grade marine ply but it was over $200 for the same size sheet. I visited three suppliers and decided to purchase from
Construction Plywoods in Airport West.
I cut the secondary cage rings with great assistance from my Father. Then the rings were placed together and the centre holes drilled for the strut bolts. I recessed the holes for the struts with a 1 1/4-inch forstner bit down to a depth of 1/8-inch, and on the outside of the rings I recessed the washers so they are flush with the timber.
I routed a recess for the focuser board which will curved to match the inside tube. I will make that next week, hopefully when the
Starlight Instruments Feather Touch focuser and the
ProtoStar secondary mirror and spider arrives from the US.
I will attempt to bend a length of pine into a curve to match the curve of the rings.
I am using brass bolts and washers which I feel will complement the rich baltic stain I will give the timber. I have always liked brass fittings and fasteners on timber products. Now I'm off to buy some stain...