Here are more details of the tripod and binocular head.
The tripod was made from:
- two small triangles (minus corners) made out of jarrah. They're easy enough to do with a miter saw, everything's a 60 degree cut.
- four slats of wood, one cut into thirds.
- nine hinges.
- Noticing that it was pretty much just the right size, I cut gaps in a lid off a fish oil capsules jar so it would fit over the tripod head, then two compact disks and the waxy paper from the jar lid, and drilled holes through them. It works quite well as a poor man's teflon.
The tripod was fiddly, but I'm quite happy with how it turned out. It folds up nicely and when deployed the spreaders keep it all nice and stable. I could probably stand on it and it would hold me.
The binocular head was simple enough. Just a few pieces of a narrow bit of wood, with the offcuts from those triangles glued on with PVA to make a nice 90 degree brace. (The bigger braces at the base of the fork are also offcuts from the triangles, I hadn't planned to make them that way but only realised I could use them while looking over my pile of offcuts when I was almost done). I drilled a 16mm hole in the wood to hold the binoculars with a spade bit and cut down into it, then tidied it up a bit with a file. Then after sitting the binoculars I worked out where to drill the 3mm hole to hold the binocular's mounting screw through the front piece of wood.
The binoculars can be moved around quite smoothly and easily with the handle that sticks out forward, moving altitude and azimuth simultaneously. I also found it makes quite a nice sight for the binoculars, looking down the length of that piece of wood I can point it at things and get them in the field of view every time. I'm thinking of putting a couple of little picture loop things along there to look through, but they might not work so well in practice because it's too dark to see them properly and I can't focus on stars at infinity and the loops at the same time!
Aesthetically it might look a little nicer if I were to round off or at least cut the corners off the top of the forks, but I realised as I was putting it together that leaving them squared off like that is very useful because it means I can stand it on the ground upside down and this is often an easier way to get the mount onto the tripod and do up the screws than trying to do it right way up.
The forks had to be widened because I needed access to the nut for tightening. That's why the main lengths of the parallelogram are reinforced like that in the middle. It's more about making room for the nut than reinforcing the pivot, but if it offers reinforcement too that's a bonus.
Total parts for this, excluding the wood:
- 6 75mm M10 bolts - 1ea for the 4 pivots at each corner of the parallelogram (plus 4 M10 nylon washers each), the fork azimuth pivot (plus two M10 nylon washers) and the binocular altitude pivot
- 2 125mm M10 bolts for the central two parallelogram pivots (plus 4 M10 nylon washers each)
- 1 145mm M10 bolt for the first azimuth pivot at the binocular end (plus two metal and two nylon M10 washers)
- 1 30mm M8 bolt for the binoculars' own azimuth (now equipped with a wingnut to facilitate quicker removal of the binoculars)
- Nine hinges for the collapsible tripod
- Various wood screws.
- Four compact disks, used in pairs at the fork azimuth pivot and the binocular altitude pivot, plus the lid of a fish oil capsule jar.
The cantilevered beam at the binocular end was only screwed onto one of the vertical sides of the parallelogram. Being jarrah, and using five wood screws, I'm confident that it will hold. It's certainly stronger than the pine beams.
The tripod was a bit fiddly but worked out pretty nicely in the end. If the screws were a little flatter in the hinges it would fold up even more compactly, I'll get onto that when I feel like it.