You’ll see in a number of pictures, the use of a large slab of aluminium that I had to make up to allow the bottom section of my 12 meter mast to clamp to a pole. A pair of standard of 2 inch double clamps wouldn’t fit Moonraker’s fibreglass mast. The bottom diameter is 58mm (about 2 1/4 inches). I found this slab on eBay and won it for a tenner. It’s heavy though – don’t think it’s a light just because it’s aluminium. Of course, in steel it would be loads heavier.
It is such a handy piece of hardware that I sometimes wonder what I’d do without it, particularly as I was bright enough at the time to drill a few extra holes in case I needed them (which I do for the 40m dipole!)
I’ve also discovered that the top 8 meters of my fishing pole fits perfectly on the 12 meter mast with a piece of plumbers tube as an “insert”. The 12 meter mast fits on the 6 meter aluminium pole too. That’s a 5/8th for 40 meters or a full sized quarter-wave for 80m!