I completed the secondary cage struts today. I have shown three struts in the first image but I have actually completed four of them. After much agonising over the final diameter, I chose 1 1/4". The struts are exactly 12" long (
Kriege suggests 11" but I like even numbers). I polished them with some 1500 wet and dry paper and they look good, but I'll probably end up covering them with foam tube from Clark Rubber.
The threaded inserts I eventually bought are an interesting variation from the type shown in
Kriege's book. They have one set of "teeth" and a flanged end, both of which are pressed to each end of the thread. The flanged end fits neatly into the end of 32mm aluminium tube with a 1.6mm wall thickness.
Phew!! At last some progress!! Next week, the secondary rings. Meanwhile, I've ordered a 3.5" secondary mirror, spider, mirror holder and anti-dew heater from
ProtoStar tonight!
hoo roo,
Steve