How to properly support the shutter wheels?

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Thursday 25th 42F. Rainy start. Still very dark at 08.00.

Yesterday I spent some time fiddling with the new skate wheels on the right shutter. I kept adding spacers to make the shutter concentric with the dome. A couple of 10mm nuts outside the wheels was all it took. The problem was an increase in cantilevering of the wheels on the extended axles.

Properly supporting the wheels has become the latest hurdle to overcome. Do I need a channel of some kind to reach over the wheel without being too bulky? I looked at using brackets from the ribs at the side but the geometry is all wrong. Everything I add has to, quite literally, pass through the slit ribs. Which means cutting more rib away. 

I could make a much more sturdy axle with the 8mm bolt as an extension. Then all I have to do is fix the axle immovably to the shutter. No idea how that would happen.

A really stiff piece of angle could be fixed to the shutter bottoms to support 8mm, stainless steel bolts as axles. The plain shank on bolts is larger than the M8 thread. Reducing the present, excessive slop. Clamping the bearings lightly with the provided middle spacer will increase load bearing.

Making the angle profile the full width [and depth] of each shutter would add greatly increased stiffness. The wheels could then be properly supported from only one side. 

A third wheel in the center of the shutter would help reduce the cantilevered and local loads on the other two. Four wheels even more so. I have eight!

I quite favour this idea. Though it needs the shutter, bottom boards to be beefed up and properly fixed. Or completely replaced. I am presently using off-cuts from 2x4 softwood. Not ideal as the wood can't resist localized loading from the foolishly extended axles.

The angle profile, wheel support could be bracketed directly to the shutter ribs. I still need to bridge the curved [highly asymmetric] gap to the GRP shutter covers. 

Up to this point I haven't fixed the covers to the bottom boards. Relying instead on the multitude of brackets fixing the covers to the shutter ribs. The softwood bottom boards were only temporary to see how things progressed. They were only put there to hold the drawer slides. Which have proved to be completely inadequate.

If I can find aluminium angle profile wide enough I can shape it to reach out to the GRP covers. Then I can bracket to the covers as well as the ribs. Allowing the use of the matching 10mm bolts where they are visible on the outside of the shutters. Which way up for the angle profiles? They could have the open side up. To allow easy access to the axle bolts. This is all beginning to take proper shape.

Now I just have to find two, sturdy, angle profiles nearly 60cm long. It looks as I shall have to cut up some of my [scrap] 5"x5" aluminium, box section tube with 5mm wall thickness. To make two, very wide, angle profiles. I was saving this material for the cross-axis mounting. If I can't complete the dome I won't need a new mounting!

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