Author Topic: Giant binocular  (Read 1177 times)

chips and more

Re: Giant binocular
« Reply #30 on: October 19, 2018, 08:50:07 AM »
You are doing one hella of a project! Did you cast those aluminum end pieces? How is getting material and other supplies in the down under part of the world? Hope your dream comes to life soon!...Dave

savarin

Re: Giant binocular
« Reply #31 on: October 19, 2018, 11:35:53 AM »
Thanks. The bosses are from a chunk of 100mm dia real aluminium not the gummy stuff I cast.

Most raw materials are available but sometimes a tad expensive, good job theres the internet.

savarin

Re: Giant binocular
« Reply #32 on: October 21, 2018, 06:50:09 AM »
 This is roughly what I will be doing for the pivot bearings.
I'm considering casting those wooden blocks in brass and squaring them up on the lathe, boring then for the shaft splitting them so they can be finger tightened and hinged for easy assemblyand bolting them from underneath that blue cap (I'm changing this from a cast ally part to a steel fabrication) I first thought of casting them in aluminium but decided brass would be better with no galling.
Can anyone think of a reason not to use brass or if something better could be used.


I have decided to make the internal unit that holds the bearings for the azimuth system from some steel plate and short lengths like the bottom unit of the pier.
This meant I had to weld both sides of some 150mm wide plate so I could turn a 154mm dia circle.

I hacked the corners off with the trusty old angle grinder and turned it using a braised carbide tool that I ground to a sharp edge and left a small flange that will sit on top of the tube.

Then I flipped it around to bore a recess to hold a 90mm dia taper roller bearing.
Not finished yet but it was tea time.




chips and more

Re: Giant binocular
« Reply #33 on: October 21, 2018, 07:08:24 AM »
How heavy is your GB getting to be? Brass blocks sounds like a lot of weight unless you hollow cast them? Some plastics are hella strong, like Delrin, but your wallet will take a big hit for blocks that big! You could cast the blocks in aluminum and make Delrin bushings to fitůmaybe? Or some other kind of bushing material that is gall resistant and slick for a nice bearing surface.
« Last Edit: October 21, 2018, 07:13:44 AM by chips and more »

savarin

Re: Giant binocular
« Reply #34 on: October 21, 2018, 07:30:34 PM »
Yep, its getting heavy. Its a strange dichotomy, weight means more stability, a breeze wont move it but more weight means more inertia when slewing.For comfort it will need two people to move and assemble it, I can just do it my self but its a struggle.I guess the next one will be the ultra light.

4GSR

Re: Giant binocular
« Reply #35 on: October 21, 2018, 07:42:26 PM »
Need a Warner & Swasey dividing engine to go with your telescope?

Woah, wait a minute. That stuff is history now days, it all done digitally.  What kind of precision movement instruments do they use now days?

Ken
Ken

savarin

Re: Giant binocular
« Reply #36 on: October 22, 2018, 03:36:25 AM »
one of these?
I had to look it up ::)

savarin

Re: Giant binocular
« Reply #37 on: October 23, 2018, 08:01:15 AM »
finished the first plate for the azimuth bearing.

this sits into the main pier tube

and the 90mm taper roller bearing sits into the recess.

Normally I would use a thick enough plate so the bearing can sit in it deeper but I didnt have any other material.
So a major question - as there is no real pressure on these bearings and zero speed do you think the small recess is sufficient to hold them?
They cant move sideways and will be set with locktight
The plate than holds the altitude bearings will sit on this.

chips and more

Re: Giant binocular
« Reply #38 on: October 23, 2018, 08:24:55 AM »

Not sure about using Loctite? Maybe not enough lip for the Loctite to work? But if you hold the bearing into place mechanically, that should do it. Looookin gooood.

f350ca

Re: Giant binocular
« Reply #39 on: October 23, 2018, 08:29:30 AM »
The small recess should locate it fine. Could you make a cap that goes over the bearing with the top at shaft size to keep the bearing covered, then bolt the cap to the plate.

Greg

savarin

Re: Giant binocular
« Reply #40 on: November 01, 2018, 10:17:37 PM »
Finished the bearing assembly and it slides into the tube easy but firm.
I will drill and tap some fixing holes once the tube is cut down to size.
I parted off 4 lengths of 16mm stainless, so easy now I have the solid plinth. (thanks Bill)
Now I have an excuse to use my latest acquisition, a crotch centre.
Mounted in the crotch centre, drilled, tapped 8 x 1 mm, counter bored 2mm for the bearing clamps (when I get them cast)I started threading the 8mm rods that will screw into these but had something happen I've not heard of before.
The die broke in half and all the cutting teeth on one set snapped off as well.
It happened when I backed off the die and it seemed to jam, wouldnt go forwards or reverse, this was by hand no power.I assume it was hardened but not tempered, bugger. (no pics as I threw it across the shop in disgust)