I am holding one of the six cannonball rollers assemblies I used
for the roll off roof structure. Cannonball track is basically a
piece of pipe with a slot cut down its length. The rollers fit inside
the pipe. These rollers are originally designed to hold structures
from the ceiling. I thought they would work inverted. That
is, I mount the track on top of my walls, and attach the rollers to the
underside of the roof. There are some problems with this. Preliminarily,
it seems the roof wants to roll not on the rollers, but on the head of
the support bolt (seen here just below and to the right of my thumb).
The roof still rolls, but not as freely as I would like. Still, the
rollers give the roof added protection from being blown off in a high wind
(a problem that I really worried about). With the rollers in the
tracks, the only way the roof can be blown off is if it takes the tracking
with it (unlikely).
Here are two additional views of the rail assemblies. The left
shows the cannonball track and attaching hardware. Right shows the
completed roof assembly from inside the observatory, and the hole through
which the outside rail will travel.
