Dome building.. and un-building.

 *

I spent the morning cutting more vertical struts and fixing the levels of the horizontal struts to match.

Then I decided it was long overdue that I cut the base ring flats. So I ran a broad pencil along the base struts and then dismantled the dome. The gores take only about five minutes to un-clamp and move them out of the way. The slit frame is a bit weighty because of the added gores on either side. So I lowered it halfway onto a stepladder. Then down onto the ground. It was manageable after that.

I sawed around the base ring cutting off the overhangs with a jigsaw. The dome needs to shed water so a round base would make a complete mess of the dome's 16-sided skirt. Now the lower panels can safely overhang the base ring.

The next step is to mark the center of the base ring and run a router around to make it smoothly circular. There were also some overlong screw points to smooth away from underneath the rings. Finally I can add a layer of oil treated hardboard beneath the ring as a smooth running surface.

Wednesday: I checked for ovality with the cross in place using a beam compass. Then I added my cheap, Chinese router to the radius arm. It felt solid but was not stiff enough. When the router bit dug in it caused waves on the running surface. So I added a second beam to make an A-frame. With the pivot on the top point of the A. If I was doing this regularly I would have added fine adjustment for radius using a cross drilled stud at the pivot. [All thread].

After a pause for rain and lunch I returned to routing. The problem was the cross of boards I had used for bracing. They stopped the router from allowing a bearing guided trimming bit to run freely right round. Another Catch 22. I couldn't lift the ring without its supporting cross. Nor, later, when I wanted to lift the entire ring up to test it on the dome supporting rollers. Then the big mounting was in the way when I wanted to fit the ring with the cross still in place.

Then it started pouring down with hale thrown in. I tidied my tools away and abandoned work for today. The ring is safe draped partially over the rollers. I shall have to remove the Torx screws to rid myself of the cross braces before I can lower the ring onto the rollers. Even then I still have some routing to do.

If only I had the wisdom of perfect hindsight! I could have moved the crossed braces into a rectangular form. Then I could have finished the routing down on the ground. Before lifting the ring upstairs and easily over the big mounting.

Thursday: It's bright but breezy today so I shall start by relocating the cross braces. I was soon able to get the ring on top of the rollers. A couple of minutes with the router removed the uncut overhangs. After that the ring turned effortlessly on the rollers.

I moved one skateboard steering wheel towards its roller and then lowered the ring back down  to the ground with parallel braces. Not nearly as good as crossed braces. All the while it kept blowing, raining and hailing for a few seconds at a time.

Click on any image for an enlargement.

*