The Giant Binocular

Now its beginning to look like a binocular.

I had to strip down the lazy susan bearings as there was a touch of stickyness in their movement.
A good clean and re pack and now they are very smooth.
They do not need to move far, just enough to spread the eyepieces from 50mm apart up to 75 mm apart which should be sufficient for most people aged from 12 to 100.
To rotate the top cages I will be using a sort of lead screw with a moving nut to pull or push them around.
So first thing is a thread and I elected to go with M8x1 in stainless so I single pointed it.

I did run a die down the thread once cut as a check and it was smooth as silk.

The knob is a chunk of cast aluminium turned to size, knurled and threaded M8x1.
Now a large nut is required and I want it to be brass. Unfortunately the only brass I have is a chunk of failed casting, its almost a bit of sponge there is so much porosity in it but what the hell, lets give it a try and see what happens.

I cut that bit off with the angle grinder and chucked it up to get it square.

Faced this side, flipped it to face the curved back side then both ends till I ended up with a block.
Drilled and tapped M8x1 and it screwed on the thread very smoothly

The top face of the nut will have a layer of very low friction polymer (plastic milk bottle) where it slides along the top plate.
Next, the bearing blocks.

Finished the eye distance mechanism finished.

and from underneath

The vertical 6mm screw will be the pin that moves the two top cages.

Wow it's really coming together!

The IPD adjustment works very smoothly with no discernable backlash
view from the rear, the long screws will be replaced when the new order arrives.

and from the front

Although there have been no posts of late here I have been working on it.
I hit a major stumbling block.
The cool captured thumb screws and alignment pin system of holding the two assemblies together worked extremely well but also made it very difficult to separate them. Also I felt that that method will chip off the paint so they had to go.
The new design is what I was going to use originally before I got too clever for my own boots.
Three sides of each hexagon will have vertical flanges with a thin rubber coat so the top section will just sit in them.
There will be a rubber pad for the top section to sit on as well. Depending on how this pad compresses will decide if I change it for plastic.
They will be held together by 6 suitcase catches on the outside.
All the fixing screws that hold the two sides together in alignment need enlarging so there is some wriggle room as current alignments are out by a few mm in twist, yaw and x and y planes.
It aint much but may cause problems later when trying to allign the optics that have to be perfect.
Still no pics as I dont have access to my computer yet.

Very cool build is an understatement.
Great work man!

Thanks, its going to be a long one.

Back working at last.
Made up 12 of these pre drilled 3mm to be welded into the frame.

Once welded in they were ground flush and tapped M5 all the way through.

The current screws will be replaced with knurled knobs (why wouldnt you) with long threads so they wont need to be fully unscrewed at night.

The rubber section gives a death like grip without marring the future paint job.

4 down, 8 to go.
The new thumb screws to hold the sections together.



19mm stainless rod, turned down to 11.5mm, then turned down to 5 mm



threaded M5



knurled with the camjack knurler



the amount of pressure required to knurl this stainless was huge.



parted off, nice long swarf curls



a bit of embelishment just because.

Very nice! Elegant. I still have knurling disfunction...
R