Dome build: Base ring adjustment.

*

Thursday: It soon clouded over but remained dry. Everything always takes far longer than I think it will. Lowering the mounting took ages to do it safely. Because I had to guy the ladders with ratchet straps.

Then I was able to center and measure the diameter of the base ring with it lying on the 2x8 octagon.

In the end I had to cut off quite a chunk of ring to reduce its size and then re-cut the half lap joint. The laser rangefinder was in use again confirming the diameter of the ring to within a mm or two. Dull weather, or even dusk, makes it far easier to see the red dot. Then the device has to be stabilized while a reading is taken with the spot centered on the narrow plywood ring 10' away.

This is the first time I have had the ring on a reasonably flat surface and easily accessible. Two opposing posts of the octagon are closer together than the others. Not that I can do anything about it at this stage. The whole structure is absolutely solid. I'll just center the ring as best I can and then mark the 2x8s ready for fixing the wheels. After that I can fix the timber brackets.

There will be a conflict in the coach screws overlapping the brackets because I couldn't get the exact length I needed. If I cut the screws off they will rust on the cut surface.

There was no obvious way to have the wheels situated over the posts. The logical answer is to move the wheel trucks a few inches anticlockwise. The wheels can then be bolted straight through the 2x8s without any problem. I have drawn arcs on the 2x8s as a guide to wheel placement using the base ring as a stencil. The lines can also be used to guide a jigsaw to curve the 2x8s. It started drizzling mid afternoon so I packed everything away by 4.00.

Friday: Dull and grey but dry. I now have two wheels bolted to the 2x8s a couple of inches away from the nearest octagon posts. I inverted the coach screws to put the domed heads down. A tap of the 2x6 and a Bessey F-clamp was enough to indent the heads into the cross braces. So that the 2x6s fitted tightly underneath the 2x8s for extra support. It looks much neater too. Though the cross braces were never intended to be visible. Being hidden eventually by the plywood cladding. Having the braces at the top of the posts will also provide a better fixing for the ply.

Click on any image for an enlargement.

*