The Giant Binocular

savarin

Active User
H-M Supporter Gold Member
Joined
Aug 22, 2012
Messages
3,094
Its time to re-visit the binocular.
This is roughly what I want.
binoscope1.jpg
I started these over 5 years ago but got side tracked building recumbent bicycles.
Now I've almost finished the refractor I've started back on these.
This is being built entirely from scratch including grinding and polishing the two 12" mirrors.
I will purchase the secondary and tertiary mirrors but that should be about it.
I got as far as building the mirror grinding machine,
machine from end.jpg machine from lhs.jpg

the pendulum grinder, this bolts to the grinding machine and hogs out the mirrors to the required radius of curvature. The motor drives a diamond disk to grind the glass and a standard grinding disk for steel for some of the tools.
overviewL.jpg

the jigs for the hexagons
hex jig.jpg

and a jig for the vertical struts.
verticals jig.jpg
I will show how these work as we go along.

I managed to make a start on the four trusses and one top cage before I put it away so thats where this project re starts.

trusses.jpg
The top cage was rusty so with a generous application of a wire cup brush on an angle grinder (do not do this at home kiddies) I removed all the rust and gave a quick spray of primer.
By the time I finished the cup brush was shedding wires and a large number of them embedded themselves in my wrist and arm.:bawling:
I had purchased all the square tube and as its just been sitting there it also rusted so I cut all the bits for the second top cage and started the derusting process on them.

pickling.jpg

You will notice there is one diagonal brace in the bottom truss, now I need to add 35 more and de rust them.
I'm thinking some plastic drain pipe with an end cap as a long holder for the derust and all the sections.

The two top cages will rotate using the large lazy susan bearings.
In the mean time I went through the older mig welder and checked it out, gas wont turn off when the trigger is released so I have to fix that but otherwise its all good.
There is a lot to do so this will not be a fast project and I expect other things will pop up to prevent me from working on it but the fingers are well and truly crossed.
 

T Bredehoft

Active User
H-M Supporter Gold Member
Joined
Dec 27, 2014
Messages
3,626
If when you get them (it) done, I may have to consider a trip to Queensland. If we're both still around. That is one awesome project. I had a friend who 'walked the stump' on an eight inch Newtonian, years ago. It seemed to take him forever.
 

savarin

Active User
H-M Supporter Gold Member
Joined
Aug 22, 2012
Messages
3,094
Hand grinding and polishing is time consuming.
I can get both mirrors hogged to the correct radius of curvature in about 2 hours.
Then I cast the tool into the hollow using steel dumps (punched centres from washers) and spin grind through the grits then spin polish to a very smooth sphere.
I will not be figuring them but flexing them into the parabola.
There are many giant binoculars in the states if you google them but this group gave me the impetus to go for it.
http://www.deep-sky.co.uk/telescopemaking.htm
They also gave me the ideas for the refractor mount.
 

savarin

Active User
H-M Supporter Gold Member
Joined
Aug 22, 2012
Messages
3,094
A quick scrub with a bit of scotch bright and they are like new.
But, they started rusting as soon as I dried them so I dunked them in the vinegar again, scrubbed them, wiped them, dunked into water and soda to neutralise the vinegar, then soahed in a jar of WD40 till ready to weld.
That worked.
They started as the rusty top one.
top-cage-1.jpg

set into the hex jig for welding,
top-cage-2.jpg

Then transfered to the vertical jig to weld the uprights in.
top-cage-3.jpg

Then flip to weld the two hexagons together and add the last two verticals,
top-cage-4.jpg

A quick touch up with the sander then a coat of primer in the hope it wont rust again
top-cage-5.jpg

Now to start cutting the 35 diagonals.
 

brino

Confirmed Tool User
H-M Lifetime Diamond Member
Joined
Jan 2, 2014
Messages
6,649
Charles thanks for sharing another of your amazing projects with us.
You certainly do dream big, but you're always able to pull it off.
I am looking forward to another great project!

popcorn.gif

-brino
 

FOMOGO

Active User
H-M Lifetime Diamond Member
Joined
Sep 2, 2013
Messages
2,934
Very nice Charles, but you're going to need a pretty good sized lanyard to hang those binoculars around your neck. :) Cheers, Mike
 
B

Bill Gruby

Forum Guest
Register Today
If I see any reflection from those on my bedroom window you are in big trouble. ROTFLMBO

"Billy G"
 

savarin

Active User
H-M Supporter Gold Member
Joined
Aug 22, 2012
Messages
3,094
Purchased the steel for the base today.
I have decided to make the feet from 25x50mm 2.5mm wall thickness rectangular steel, 12mm thick plate 150mm dia to fit inside a 150mm tube (except its 152 mm dia. when I measured it)
I have decided to make the base similar to the refractor albeit larger to account for the width of these beauties.
footplan.jpg
The two steel disks (blue) are welded to the 6 red vertical 25x12mm bars as separators, the green legs/feet hinge down for transport.
I am unsure if the deep blue sections will be required for rigidity so they may or may not be welded on.
 

savarin

Active User
H-M Supporter Gold Member
Joined
Aug 22, 2012
Messages
3,094
The steel for the disks is only 150mm wide so I cut two sections 160mm long and built up the 150mm width with weld to 160mm wide.
Wacked off the corners with the angle grinder, mounted it on a 10mm bolt with another off set to act as drive dog on one of the jaws.
bottom-disk.jpg

I used a braised carbide tool that stood up to the interrupted cut with no problems.
Here its just so you can see the weld being cut.
This was a very noisy operation as the disk rang like a bell on every interruption.
Most of the chips came of blue but quite a few came off glowing red hot and burning.
I think I may be pushing this lathe outside its comfort zone.
bottom-disk-2.jpg

Once it was turned down to 154mm dia I placed it in the 4 jaw to face it.
bottom-disk-3.jpg

This whole task to this point from cutting the steel to getting the first face cut took most of the afternoon to do.
 
It can take up to an hour for ads to appear on the page. See our code implementation guide for more details. If you already have Auto ad code on your pages there's no need to replace it with this code
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock