The Giant Binocular

[T Bredehoft]

a bit of embellishment just because.

Just Because is a better reason than many others.

 

[Janderso]

Nice work,
I too have knurling disfunction, have yet to successfully knurl anything.

 

[savarin]

The clips are done and the whole assembly holds together solid.

Now they are clipped together another problem has reared its ugly head, welding distortion.
The two side plates that the pivot will be bolted to do not sit parallel when bolted up, on one side the truss is slightly warped.
To solve this I made four exact sized spacers from some thick walled aluminium tube and bolted them together.
when turning the spacer tubes they got pretty hot from the friction of the steady and expanded.
I had to wait for each one of them to cool to ambient to get the real measurement and then finish off their length.
They came out to within 2 thou of each other. I felt that was close enough.
This has worked to get the side plates spot on parallel and square.
Now I will bolt the two trusses together using shims to take up the slack and keep them parallel.
Here they are just sitting at the top of where they must go.

After sorting out the central plates and re-aligning the vertical trusses I had to make a new bottom plate.
I first cut the half circle section out where the main support will fit with a jig saw which was not very accurate but I stayed inside the line.
Then milled it to size with a 4mm end mill in the drill press. (yeah yeah I know you shouldnt but it worked).

Then I smoothed the milled cut with a flap sander, it doesnt actually touch the table it just looks like it does.

Once this bottom plate was in place I could bolt the whole assembly back up and find the balance point.

To get a more accurate idea of where it should balance I added the glass blanks for the mirrors and more metal to take the place of the mirror cells and a package of the four secondary and tertiary mirrors and a couple of eyepieces at the top end.

It balanced 1/8 of an inch below where I thought it would have when I first planned it out. I felt good at that point.
But, we always have to have one of those, that 1/8 of an inch placed the central hole in the pivot just off the diagonal brace so I had to cut a small section out.
Bah humbug. Actually because there is a plate bolted all around that section I dont think it needs the diagonal at all so I may cut it completely out once I tear it all down again or weld in a bridging section.

 

[savarin]

And the pivot fits in

 

[Downunder Bob]

G'day Charles, I can't believe how long you've been building this and I've only just discovered it. Another one of your amazing projects. proving to us every day that you can do things we all know can't be done. I take my hat off to you once again. I only wish I could get half the shop time you obviously have, I'm lucky to get an hour a week.

Well done.

 

[savarin]

Thanks Bob, I would like to say that retirement allows more time in the shop but unfortunately it doesnt.
I get about 8 hours total a week and I find it very difficult to work more than around 3 hours in one day.
So, still a long time to go.

 

[Boswell]

I enjoy reading about your project. It is comforting to see someone as skilled as you having to do minor re-work occasionally as you uncover issues not accounted for in the original process. Helps me feel better about my own design to build process.

 

[savarin]

Ha Ha, a hell of a lot of that goes on

 

[Downunder Bob]

Funny you say that retirement allows more time in the shop, but it doesn't. I Bought my lathe a couple of years after retiring, because I was bored. But before I got started on anything, my wife had a very serious stroke, She is now recovering after nearly a year of complications, during which she made very little if any progress. She is now doing well, and we are hoping that by next April she will be more or less independent.

During that first year I Think I got a total of about 6 hours shop time, then gradually increased so that now I'm getting an average of about 3 hours a week. I have begun my first major project, which is a substantial vertical spindle milling attachment for the lathe as I simply don't have room for a mill. I( would love a small bridgeport or clone thereof. I'm hoping it will be operational, if not quite finished, by April next year. I'll start getting some photos up soon, and start the story.

I can already do some horizontal milling and have been quite impressed with the rigidity of the machine.

 

[savarin]

Now thats a project I will be hanging out to see.
I have my old small drill press just sitting under the bench that I thought of doing that to but decided I have too many other projects waiting in the wings.