The Giant Binocular

[savarin]

Good news on the regrind The new tool conformed in 30 seconds.
I plastered the mirror and tool with a sharpie pen,

800 grit small wag and overhang and this was the wear after 30 seconds only.


After 35 mins I almost removed the scratch from this (quite deep)

to this

Barely noticeable, and best of all the focal length didnt measurably change.
Phew, its working.

 

[woodchucker]

congrats on getting past a near disaster.

 

[savarin]

Almost removed the gouge, just a teeny little pit virtually invisible but the blue laser shows it up when shone in from the side

 

[savarin]

All gouges and scratches removed, focal length has reduced from desired 72" to actual 70" but as long as I get the second mirror down to that theres no problem.
Did some major milling today. The base for the polishing lap was around 8mm higher on one side than the other so I had to mill it flat.
No milling machine, wont fit on the lathe so I milled it on the drill press.
This side must be milled down to the pencil line.

As its only plaster I could hold it by hand and move it around till I got it evenly flat.

Now to pour the polishing compound on to it when it totally dry.
4 hours in the oven at 90'C didnt dry it fully.