Uni strut for roll off roof rails.

[vk6kb (Keith)]

A friend suggested the 41 x 41 x 2mm Unistrut mounted upside down, ie with the opening at the top, would be an ideal track then you can use four or six of the 4 wheel roller assemblies attached to the roof in the tracks.
I think I'm going to go this way and I'm wondering if anyone else has done this ?
My roof will be 3 mtrs long and 2.2 mtrs wide and fairly light, possibly dark coloured plastic roof sheets.
The whole obsy is being made from patio tube, 76 x 36 I think it is, with steel sheet cladding, all sourced for free from my local radio club
Cheers

[Goschencat (Rex)]

Hi Keith. I’ve used upside down unistrut on my mini obs for the roof rails and it works fine. I didn’t used the wheels you mention. I opted for brass rollers running on top of one of the sides if the unistrut. Then added a T section at each end of the roof that runs inside the unistrut as hold down, preventing the roof lifting at all.
Good luck with your build.
Cheers
Rex VK3OF

[vk6kb (Keith)]

Thanks Rex,
I've sourced some locally so with go have a look at how the rollers fit.
73 & Clear Skies

[tempestwizz (Brian)]

I’ve used the channels and rollers from panel lift garage doors in an earlier build. After a diplomatic approach to one of the garage door companies I managed to acquire for a modest fee, a range of channels and wheels removed that had been removed as part of a refurbishment program for more a modern style for their customers. They had piles of second hand channels and wheels that were no longer of use in their current projects.
HTH

[Zubenel (Wes)]

I am "testing" unistrut as rails as a C section type arrangement on the cubby house/trust roof I built for the kids 25 years ago. ( the grandies need better ...) The reason was I want the up lift and water problem engineered out . I bought standard rollers off amazon and have ground down 4 so far to 35mm +-0.1mm .They roll ok .The brackets for the rollers only arrived today so I look forward to swapping out the drilled timber blocks .

[vk6kb (Keith)]

Originally Posted by tempestwizz

I’ve used the channels and rollers from panel lift garage doors in an earlier build. After a diplomatic approach to one of the garage door companies I managed to acquire for a modest fee, a range of channels and wheels removed that had been removed as part of a refurbishment program for more a modern style for their customers. They had piles of second hand channels and wheels that were no longer of use in their current projects.
HTH

Thanks for the info , I've been to both Unistrut and garage door suppliers today and I think I will go with the garage door track, specifically the track from B & D garage doors which has a back strengthener in the track and the rollers are 2 mm bigger in diameter.
The unistrut works out about $100 dearer as well, and the track has more play when the rollers are fitted.
As soon as our temps drop below 30 C for a week I'll start the concreting.
Thanks for the advice folks, and I may still change my mind if I can find any free stuff
Cheers

[vk6kb (Keith)]

Well the two garage door rails didnt work
Because the roof is sloping there is too much weight on the bottom rail/ rollers causing all sorts of grief.
The roof attempts to " crab" along using the drive gear and toothed track, mainly because the weigh is unevenly distributed ( I think).
So today I've bought a V groove track for the lower wall and V grooved wheels to run in it. Hopefully this will make the bottom side more " rigid" and allow the upper floating wheels to run better in the top garage door guides.
Cant work on it for a week due to family things but will attempt to swap it over, fingers crossed !!
Any suggestions ?
Cheers

Incidentally my wife reckons if it doesn't work it will make a good kennel for our two big dogs, so she has nicknamed it the " Dog Star Kennel ", Sirius'ly

[Leo.G (Leo)]

You could always try a counterweight system to even up the weight/load if applicable?
From memory I believe I've seen a system as such done with ropes and weights on here somewhere in a roll off roof discussion.

I was a supervisor at B&D many, many years ago in Mascot (Sydney), their tracks were strong back then but I know many manufacturers are making cheaper grade components now to maximise profits and reduce overall quality/longevity. I can't say B&D are actually doing this as I have no idea but I know a lot of places are.
We can't have everyone driving around in 33 year old cars like mine as of next month, nothing is supposed to last that long now.

[vk6kb (Keith)]

Thanks Leo,
I don't think its a quality issue, more of the roof being at a 17 deg angle and preventing the two sets of floating rollers from finding a " happy spot" . I will try the fixed rollers first and see.
I checked the whole thing for " squareness" today and its within 5mm so it has to be due to weight and the floating rollers.
Time will tell.
Thanks

Originally Posted by Leo.G

You could always try a counterweight system to even up the weight/load if applicable?
From memory I believe I've seen a system as such done with ropes and weights on here somewhere in a roll off roof discussion.

I was a supervisor at B&D many, many years ago in Mascot (Sydney), their tracks were strong back then but I know many manufacturers are making cheaper grade components now to maximise profits and reduce overall quality/longevity. I can't say B&D are actually doing this as I have no idea but I know a lot of places are.
We can't have everyone driving around in 33 year old cars like mine as of next month, nothing is supposed to last that long now.

[vk6kb (Keith)]

Well it'd taken many weeks of head scratching, trying different things and at last it works.
I've ended up with a fixed track with 73mm heavy rollers at the lower part of the roof and floating garage door tracks at the top.
I would advise against doing what I did with a sloping roof , rather build the walls level then add a sloping roof to the Obsy.
The imbalance of weight versus gravity made it really difficult to get the roof to not try to slide down to the lowest point.
Anyway it now works, the motor drive works and all I have to do now is sort out the limit switches for the roof and extra limit switches to the Arduino to keep NINA informed as to where the roof actually is.
I think you go into these project with a fixed path to follow, well mine has more bends than Bathurst
Hopefully I can now get the rest sorted, security, power ( all 13.8vdc) and then instal some scopes
Cheers

[Leo.G (Leo)]

It's good you got it all sorted Keith. It must have been quite the challenge with the sloping roof. As I age I'm soon learning gravity always wins.
I have it in my head I could design a flip roof if I'm ever in a position to buy my own place (I'd have to rely on the Lotto Gods for that to ever be remotely possible). It's funny, going through the design in my own head and I see the point where gravity takes over and opposes everything I'd want.
Of course my design would be an observatory on top of my 2 storey house with a glass dome which flips in the middle, or a huge iris. The iris design would work better but water ingress would be an issue.
Yes, I'm a dreamer!"
But I'm not stupid, there would be piers sunk at least 15 metres into the ground supporting the structure to limit vibration.


Don't cheap out on the power supplies.

[vk6kb (Keith)]

Thanks Leo
One thing I'm not short of is power supplies
I have at least 6 at 20 amps and a few 60 amps as well, all from my Ham radio gear.
I have a nice high quality 30 amp switched mode lined up to do the job.
I'm sorting out the security at present with mag locks on the door and a few other tricks
You cant stop thieves but you can make it as difficult as possible.
I had first light the other day , just with my Seestar and it was nice and easy to operate the roof etc.
Cheers

[Leo.G (Leo)]

An easy to operate roof sounds great. An old saying is locks only stop honest thieves but in this day and age I'm very security conscious, especially living in a department of housing premises. I have security cameras everywhere, even in the tool shed.
My son has designed and modelled a system with K'Nex to make a safe door mechanism for the tool shed which holds a lathe, milling machine and some expensive welding gear along with numerous other power tools and accessories for the machines. I've yet to buy the steel and alloy for the door frame and mechanisms but it will be interesting, it's a very clever system. The design incorporates both mechanical and electronic locking with both being able to over-ride each other. The most important thing is the magnetic/electric locks come as fail secure or fail safe. One means power outage and the locks release while the other remains secure in a power failure. If you're going that route make sure you get the right units.

[ad602000 (Pete)]

I have often toyed with the idea of using "barn door" tracks and using the door fittings and wheels to attach to the roof, but my backyard is to small for a roll on roll off
cheers
pete