Motorising the Observatory Roof
First Problem!
The roof was built to run on makeshift tracks. I used pairs of old bookshelf supports, the sort you clip the shelf brackets into. I used 4 U shaped pulleys with centre bearings mounted on M6 bolts set into wood blocks. Two supports were screwed on side by side so give a thicker stable 'rail' in the middle. This was ideal at the time, low cost and easy even if it used 16 metres of supports! (4x2m each side to give two 4 m tracks).
Opening the roof by hand was OK but I was advised by a friend who had been this route that the roof needed to roll very freely for motorisation, so the rails had to be changed. The replacement wheel to go on the new rail is a wee bit bigger!
Second Problem!
Th roof rolls off onto two 2 m lenghts of joist, When I came to remove the old track I found they had rotted along the top. Luckily I had some spare joist left over - they came from an old outbuilding that was demolished to make way for our house (see Observatory Build page).
The Fix :)
Cut the joists to suit, make joints, clean surface and apply loads of coats of exterior varnish (spare tins, different tints were available!) and screw it all together, sealing gaps with builders silicone.
The rear joist is supported by a large piece of ancient iron banged into the very ancient wall.
New wheel in place on nice new shiny rails (both bought on ManoMano,fr at reasonable cost) with the old one still in place. I took the opportunity to raise the roof a little as it fouled seasonally as the wood dried and shrank in the summer.