Welcome to East Midlands Stargazers

Register now to gain access to all of our features. Once registered and logged in, you'll be able to contribute to this site by submitting your own content or replying to existing content. You'll be able to customise your profile, receive reputation points as a reward for submitting content, communicate with other members via your own private inbox, plus much more! This message will be removed once you've signed in.

Graham

Mirror Grinding Experiment

36 posts in this topic

Well I have decided to have a crack at grinding my own mirror.

I will do a step by step log as I go.

I will be attempting to grind up a 14 inch mirror.

 

First thing I will be doing is making a fixed post grinding machine.

I might at a later stage convert this into a Carl Zeiss type machine for the polishing stages.

 

Well I have gathered together all sorts of bits and bobs in preparation for the build.

The drive system I salvaged from my old pillar drill.

It is a multiple pulley set up which gives me twelve speed ratios.

I used to use this set up for cutting and polishing gem stones so it is a tried and tested drive system.

 

First thing I had to make was a large flat turntable.

This is constructed from three layers of 18mm thick plywood.

It is 500mm in diameter. 

The layers are glued and screwed together then the complete lump was mounted to a 10mm thick steel backing plate.

 

In the centre of the backing plate is a 25mm steel shaft which is a machined fit for the bearing carrier.

The carrier consists of a top bearing which is a tapered roller bearing and a normal type sealed roller base bearing.

 

Several coats of Yacht Varnish later and this is the result.

 

 

 

 

 

Turn Table.jpg

 

 

I will post up more as I build it. :)

 

Edited by Graham
rowbow, Tweedledee, Werisit and 1 other like this

Share this post


Link to post
Share on other sites

Looking forward to this Graham.

 

I would love to give it a go and one day I will but I will let you go first and learn off you :thumbsup:

Share this post


Link to post
Share on other sites

Fantastic stuff Graham, will be following this with interest.

Share this post


Link to post
Share on other sites

Good luck Graham, this will be a fascinating project to follow.

Hope it goes well :thumbsup:

Share this post


Link to post
Share on other sites

Thinking outside the box Graham would it be possible to use the CNC lathe or Milling machine you have access to and machine the radius of curvature needed to achieve the exact depth of curve (Sagitta). I'm sure there are software calculators that will give you the exact sagitta measurements throughout the entire surface area of the mirror. Program these in and you should have an exact mirror. All that would be needed is to polish and figure it.

Share this post


Link to post
Share on other sites

Hi Folks.

Thank you for all the words of encouragement.

Wow did not realise this would cause such interest.

I will do regular updates and if I can work out how post some videos.

Mick. -- good idea but I do not use a cnc lathe or mill I do everything the proper way :) manually. ;);)

Edited by Graham
BAZ likes this

Share this post


Link to post
Share on other sites

Been down and out for a couple of days ill and only just seen this thread. I too am really excited to see your progress on this Graham :2thumbsup: :2thumbsup:

Share this post


Link to post
Share on other sites

Hi Graham I made a 8" mirror some 40 odd years ago, it gives you great satisfaction mine is a F6  and I still have it not used now

Stephen

Share this post


Link to post
Share on other sites

Did a bit more to the machine today.

First job was to recycle this wood I got from some pallets at work.

 

wood.thumb.jpg.7ee4b680ff188f7c45be38aee

After constructing the basic table I fitted the steel plate from my old stone cutting set up.

This is the main turntable bearing carrier.

 

567698ddaa262_bearingcarrier.thumb.jpg.f

I still have to fit the rest of the cross braces but this is the Turntable in position.

Next job will be to cut all the plywood sheets to cover in the frame.

This will be done at work on the water jet.

 

56769965aeda4_tablebuild1.thumb.jpg.126d

Share this post


Link to post
Share on other sites

Wow that was done quick.

 

Is the bench meant to wobble like that or will it all be secured down. What sort of speed controller are you going to get?

Share this post


Link to post
Share on other sites

Hi Mick

No the wobble will be gone when I get the rest of the cross braces fitted. 

The legs are only held on with a single screw :lol:

Just wanted to get it running to make sure the motor still worked.

Looking into fitting one of those controllers that adjust the sine wave on the AC input.

Share this post


Link to post
Share on other sites

Wow that's coming along quickly Graham! Absolutely awesome!

Share this post


Link to post
Share on other sites

Thanks folks.

Mick will do once I get it sorted.

 

 

 

Edited by Graham

Share this post


Link to post
Share on other sites

testing u tube vid.

 

 

Edited by Graham

Share this post


Link to post
Share on other sites

Well sort of Felix.

Still goes to the list of other videos at the end unlike yours.

Just dont know how to stop it.

Share this post


Link to post
Share on other sites

Managed to cut the panels today on the water jet.

Got home and fitted them.

 

567997003789f_table4.thumb.jpg.dc71768ba

 

 

Another view.

 

56799757ed20f_table3.thumb.jpg.9c1b6a6af

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now