draper grinding machine

[aalavandhaann]

But i wish to know one thing, since this machine uses TOT method(Tool on top) is it efficient enough to dig the saggita we need? also can polishing be done too with this machine? sorry i had been very stupid with my questions.

[aalavandhaann]

Hello dude,

Thanks for your wonderful machine. I would say nothing can be more simpler than this. I have already started making one looking at your video. I have secured a 1440 rpm,1/4 hp motor, Pulleys (they are quite heavy though) and two kinds of four pillow bearings. I am keeping my fingers crossed to see if my motor will perform the job ;-).

[LukeSkyscraper]

How do ensure that the mirror is being ground to a parabola and not spherical?

[jimbob2006womble]

You grind it spherical,

Polish it spherical,

Then figure it to a parabola

[LukeSkyscraper]

must.. resist.... oh I can't...

That FIGURES lol.

Thanks for the reply, I thought they'd made a magic parabola grinding machine for a while there.  I do have another question, if you are able and willing to answer it:

When you start with the mirror blank and the grinding tool, what exactly is the profile of the grinding tool when you first start? is it flat or curved and if curved to what curve?

[jimbob2006womble]

I haven't ground a mirror yet, just researching if it is doable. However.... mirror flat = tool flat, OR if the mirror has a roughed shape in it, cast the tool into the mirror to conform to its shape. Curved mirror, curved tool.

A bloody horrid joke btw :D

[mspacone]

What does this machine do? I have neverheard of a Draper Grinding Machine.

[nasanction]

It is used to grind glass blanks down to a parabolic shape to reflect light in a telescope to the desired focal point.

Of course there is much more to it then that. Adding the silver coating and such. It is very hard to make a perfect optical mirror. Which is why most larger reflector type telescopes are very expensive.

[mspacone]

Ahhh very cool. Thank you!

[amen2233]

groovy ...all we need is a needle and we can converting it into a record player! 2 in 1 eh???

[nhennenfent]

beautiful and thanks, where did you get your mirror blank from, what diameter and thickness is it?

[casaccio]

awesome, im interested in making a big mirror but, i need more blueprints on making the machine