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What caster's / Rollers for roll off, roll on roof?


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Keeping the roof on.

I placed long horizontal bolts through the roof at one end, so they protuded through matching holes in the shed wall. My thought was that the protuding thread would take a nut and washer as a security measure, and remove any chance of the roof sliding open in the wind. The roof could not lift directly because of the bolts.

The same solution could not be used at the other end. So I put studs near the top of the wall protuding about 50mm into the shed. The roof had drilled L brackets wide enough to fit over the studs. Again preventing the roof from lifting in the wind. The L brackets had the advantage of stopping the roof opening too far and going out of reach. General wobble (or build errors) meant for closing I had to add a couple of small guide castors to ensure the L brackets hit the suds in the right place.

A later (lazy? innovative?) feature was adding an electric garage door opener to automate the move. The locking mechanism in here meant there was no need to worry about the roof sliding about in the wind.

Security? The shed alarm system includes (along with everything else) a switch to monitor the roof being moved out of fully closed position.

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Hi Helen, I take your point and at the end of the day I guess it's down to personal choice. It sounds like this was the best solution for you and your system sounds great. At the end of the day, the k

Yes, life is full of compromises, and we all have our own ways of working out what we think is best for our individual circumstances. As we're all unique the chances are our solutions will be unique

I thought about various solutions using 'proper' metal rails. But after bringing in Messrs Heath and Robinson as Consulting Engineers, the following was adopted. The castors are running on a plastic s

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My next question is keeping the roof shut tight in the wind, was thinking "turn buckles" on all 4 sides?

Turnbuckles are a very common solution - cheap, simple and effective.

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+1 for turnbuckles as they cope with variations in position very well (important given the way wood can settle/expand/contract and the way exact consistency in rolling is difficult to achieve)

Helen

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The roof on my obsy is well over 1/2 ton and rolls very easily with basic Screwfix castors. The reason it rolls so well is the amount of casters used, and a smooth and straight track to run in. I use 8x rollers on each side of a 14' roof. I haven't had a single issue in two years.

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Just a note from what I have learned from building two observatories.

Plastic wheels are quiet-running, but wear and get flat-spots.

Metal wheels are noisier, but don't wear or get flat spots. If you are moving the roof (especially on a dome) it's usually done slowly for astrophotography so noise is not such a problem. For visual, you tend to move the dome a lot between objects and fairly quickly, so if you are living in the suburbs you may annoy neighbours with your rumbling roof in the middle of the night.

For a roll-off, this is not such a problem because you roll it off once at the beginning of the night, and back on once at the end of the night.

Wheels with just a hole and axle are cheap, but offer resistance with inertia. Wheels with bearings are much easier to start and continue movement.

Take what you will out of it. Just my experience.

Baz.

Edited by ASIGN_Baz
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Good points Bas and all valid. I used the high impact polyurethane wheeled castors which don't flatten when left standing and are relatively quiet when running. The wheels run in Dexion channel. I was given the Dexion free and accepted it with the fixing slots. I therefore had to tack a strip of galvanised steel the whole length for the wheels to run on.

Because of the amount of wheels I used, the weight distribution is such that each wheel can be turned with my fingers. I know someone who used the hard rubber type castor and they flatten when left making push off quite difficult.

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There seems to be mixed views regarding the suitability of rubber tyred wheels. Some say they flat spots, others say they are fine. I guess this depends to a large extent on the number of wheles used, and the weight of the roof.

I'm in the middle of designing my roof at the moment and admit to be very unsure which ones to go for. It seems to be a choice between low cost of rubber wheels (Screwfix 75mm currently being considered) and the risk of these getting flat spots, and more expensive metal rollers. Hard nylon wheels may offer a good compromise, although may be a bit noisier to move.

The other problem I'm having is how to keep the wheels rolling straight. Don't know whether to make a lateral guide using a low cost wood batten (with or without additional laterally mounted wheels), or whether to seek out aluminium L shape angle or channel at higher cost.

Does anyone have any recommendations of where to get quality low cost angle or channel of suitable size?

I'd also be grateful for any other opinions of functionality of Screwfix rubber wheels.

Many thanks

Kevin

Edited by Astrokev
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Hi Kevin

Your first paragraph above sums up rubber wheels. The heavier the roof the more castors you need. The example of flat wheels I experienced was on a heavy 18' roof with only 6 wheels per side. They also ran on wood with wooden guides. It took two people to get it to move.

They have since been increased to 14 castors each side with an aluminum channel for runners. It opens now effortlessly.

Metal wheels tend to run on metal, and as a consequence are inherently noisy.

HTH

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Well the casters are fitted and roof rolling great.

I went for the 50mm nylon wheels from Screwfix thought it might be a gamble at £6 for a pack of 4, but are stronger then i thought and as i bought 2 packs so i can have 4 wheels per side they work very well.

I have them spaced out at 20" centres and this seems to work very well.

As for "guiding" them in a straight line i screwed a length of gravel board to the side of the roof, not only does it stop the roof moving left or right it also helps in keeping it all weather proof.

All looked fine in yesterdays rain with no leaks but was not very heavy rain so time will tell, but i am sure it will be.

Dont get me wrong it's not the best looking obs on here as i have used a second hand shed and my rough DIY skills and a budget, so far £75 on a 5x8 shed £100 on all others bits..pier FREE!!.

But it works....allows the scope to stay set up and safe which will result in me using it more.

Was going to put a few pics up but after seeing Freff's i thought i'll wait until all the finishing touches are done.....will put mine to shame.

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Post them anyway, please :D We all like to see other builds as they progress :) Don't worry about it not being as good as some others.

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Metal wheels tend to run on metal, and as a consequence are inherently noisy.

HTH

I´ve seen a few people comment on the noise but mine just doesn´t seem that loud. The main thing is not to have 1 meter sections of rail i.e. loads of joins and every join being a small bump which clangs every time it is hit by the wheel. I have two 3 meter rails on each side with one join and no problems.

It maybe that, where I live in a village and suspect I am going slightly deaf, I don´t notice it.

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Hi Dave

Good to hear your roof is working well. I wouldn't worry about some of the other builds possibly "putting yours to shame". I'm sure that won't be the case, and we all like to see how each builder approaches and resolves the problems they encounter. I've spent ages over the last week pouring over loads of builds - pinching an idea here and a possible work-around there. The more examples we all have to refer to to help us make design decisions has got to be a good thing :smiley:

Good to hear the Screwfix nylon castors are robust, it's always difficult to tell from a picture on a website. After lots of U-turns, I'm currently favouring using Screwfix 75mm nylon castors, and running them in aluminium U channel. On browsing websites i realsied that this isn't quite as pricey as I at first thought. :smiley:

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I got my u-channel from here: http://www.aluminiumwarehouse.co.uk Cost approx. £54 for 2*5m lengths including delivery.

Thanks Mike. This definitely seems to be the best site regarding prices. The U channel isn't actually as pricey as I at first thought, so I'm making yet another design change! :icon_mrgreen:

I need to get the castors first, so I can determine what size channel I need. I'm finalising on Screwfix 75mm nylon castors so am anticipating 2" x 1" x 1/8" to be about right.

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Thanks Mike. This definitely seems to be the best site regarding prices. The U channel isn't actually as pricey as I at first thought, so I'm making yet another design change! :icon_mrgreen:

I need to get the castors first, so I can determine what size channel I need. I'm finalising on Screwfix 75mm nylon castors so am anticipating 2" x 1" x 1/8" to be about right.

You're welcome Kev. Also make sure you understand the dimensions of the profile of the channel that you intend to buy like what I didn't.

I'd originally bought the 50mm wheels from ScrewFix and thought I had chosen the appropriate profile but when the channel arrived I found that the wheels didn't fit into the channel - the channel needed to be either wider (so that the axle would have fitted in) or shallower (so that the axle was above the channel). Instead the axle simply rested on top of the channel leaving the wheels spinning in mid air - oops. :embarrassed: I think I mistook an external dimension for an internal one or t'other way round.

Thankfully it was easily resolved by purchasing the 75mm wheels which fitted the channel nicely.

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I´ve seen a few people comment on the noise but mine just doesn´t seem that loud. The main thing is not to have 1 meter sections of rail i.e. loads of joins and every join being a small bump which clangs every time it is hit by the wheel. I have two 3 meter rails on each side with one join and no problems.

It maybe that, where I live in a village and suspect I am going slightly deaf, I don´t notice it.

I keep hearing the tune to "This is the age of the train" :grin:

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Glad it worked out as you wanted it Dave.

As for my obsy, there is an ulterior motive for it looking as it does. My wife had a say in it. :rolleyes:

I'm only in Malpas, pop over and have a look.

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I've bought various things from aluminium wharehouse but you needed to buy a goodly amount to make it woirth their carriage costs. 5m ali tube for my weather station mast (in 2 sections with a smaller diameter top section).

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Thanks for all the replies guys,

I am pleased with the build so far and more so with the roof, i used the smaller 50mm wheels as i did'nt want to high a profile and this sits just nice, also quiet, the wheels work very well for the price.

I was also going to sit the wheels in a rail to insure the roof keeps straight and dont fall of but noise did cross my mind, so mine runs on Decking boards, so plenty of width and also quiet and like i said before with the boards fixed to the sides of the roof it can't fall off......which is nice

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You're welcome Kev. Also make sure you understand the dimensions of the profile of the channel that you intend to buy like what I didn't.

I'd originally bought the 50mm wheels from ScrewFix and thought I had chosen the appropriate profile but when the channel arrived I found that the wheels didn't fit into the channel - the channel needed to be either wider (so that the axle would have fitted in) or shallower (so that the axle was above the channel). Instead the axle simply rested on top of the channel leaving the wheels spinning in mid air - oops. :embarrassed: I think I mistook an external dimension for an internal one or t'other way round.

Thankfully it was easily resolved by purchasing the 75mm wheels which fitted the channel nicely.

That's why I want to get the castors before ordering the channel - just to make sure :cool: . Some sites give full dimensioned drawings of wheel assemblies, but Screwfix doesn't, so wise to buy and measure them before committing to the channel!

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