3v - 3/8 domes, useful information
Some example domes built with hubs
6m diameter, Chris is a bit over 6ft tall.
We think this is 6m diameter too, or close to it.
How many hubs?
46 in total.
- 6 x 5-way hubs
- 40 x 6-way hubs
When you build the dome, the bottom ring of 6-ways will only have four populated sockets. We use 6-ways here so that people can add another layer to their dome if they want to. You can also use two ball connectors in the spare sockets to connect your dome to your base.
How many sticks?
120 in total.
- 30 x Short sticks
- 40 x Medium sticks
- 50 x Long sticks
Our calculator tells you the lengths of stick you need for a given diameter.
Using another calculator
If you're using a regular dome calculator you need to take off 87mm from each length it gives you to account for the space that the hubs and ball connectors take up at the points. (Most calculators give you the point-to-point distances.)
- Use millimetres as your unit for accuracy.
- Using inches? – work to 1/16 of an inch.
Measured from the lowest points in the base.
- A = 0.414 x diameter.
- B = 0.384 x diameter.
- C = 0.312 x diameter.
- D = 0.278 x diameter.
- E = 0.172 x diameter.
- F = 0.138 x diameter.
- The base ring is made up of 5 x Mediums and 10 x Longs, and 15 x 6-way hubs.
- 5 of the base hubs sit on a slightly higher plane, it isn't a big difference so you can chock or shim once in position, which is what most people do.
- Note that the base ring is 0.9837 x the master diameter of the dome as the 3/8s base section is slightly smaller than the diameter at the halfway point. In practice that doesn't equate to much, but if dimensions are critical it's worth knowing that this difference exists.
You can investigate the Kruschke method which introduces an additional length to create a flat base, there is a calculator here. Checking 'Align base' at the acidome calculator also shows how to do this.
The principles of the build are the same as in the 2v; start in the middle and work your way out connecting as you go. The dome will be self-supporting as you go; growing up out of the ground. If you can't connect then you need to lift the hub above to enable the connection to be made. Our core guides explain more.
How many people?
For smaller domes 2 people can manage the build. 3 or more people is helpful for larger domes. And if you're going to lift the whole thing into position then 5 or more people is advisable.