Jovilabe

[James AlfordParticipant @jamesalford67616]

Neil,

Looks good to me.

May I ask how you transferred the image to the metal prior to etching? I have done a little etching with ferric chloride, ironing on a laser-printed image. My difficulty was getting the image to come off cleanly.

Regards,

James.

[Neil WyattModerator @neilwyatt]

Thanks James,

I spray the brass with etch-resist, then laser print a negative image onto transparency film (inkjet film works too) and then expose it with my PCB light box. I use dilute sodium hydroxide to develop the resist and etch in ferric chloride.

Neil

[James AlfordParticipant @jamesalford67616]

Neil,

Thank you.

James.

[Neil WyattModerator @neilwyatt]

This brass polishing is getting to me. Nearly all done, but the 60-t gears are particularly exposed and have no bosses (the 12-t gears are a push fit in them). Despite neatly parting them, any pause has left a ring that needs sanding out, most were OK a couple of sides took a bit of doing and one was awful. I have blood running from my right hand ring finger from pressing sharp gears down onto the wet and dry.

I will leave the fine grit and polish for tomorrow.

Bad news, I discovered three more gears will give me a 0.03% accurate lunar phase dial, and it fills the empty space on the big dial, but one is an idler so only two lots of gear cutting.

[duncan webster 1Participant @duncanwebster1]

Posted by SillyOldDuffer on 13/10/2016 14:51:05:

Posted by CHARLES lipscombe on 12/10/2016 23:07:26:

Since we have some latin-conversant contributors on this thread, can someone tell me what the latin would be for (Chas) made me, which I might stamp on some of the bits I make?

Don't trust any claims I make to being educated:

Latin is a language,
As dead as dead can be.
It killed the ancient Romans,
and now it's killing me.

Caveat emptor,

Dave

Caesar aderat forte

Brurtus adsum iam

Caesar sic in omnibus

Brutus sic in tram

All genuine Latin words, but of course it doesn't mean anything, but it kept us amused as schoolboys 50+ years ago

[Neil WyattModerator @neilwyatt]

I'm getting a bit nervous, that I've bitten off more than I can chew.

Adding 15 more gears will give me four sub dials underneath the Jovilabe proper Jupiter rotation, lunar phase, sidereal time and UTC all to high levels of accuracy.

The down side is (1) will the torque required burst it? and (2) this is about twice as complex as the Antikythera mechanism… gulp!

[Neil WyattModerator @neilwyatt]

Test polish for the sidereal dial, to go in the right-hand position (actually bottom of the dial as I have rotated the inner part 90 degrees).

Neil

[norman valentineParticipant @normanvalentine78682]

Neil, if at the end it doesn't work all you need to do is crush it flat and throw it in the sea somewhere coral will grow over it. Then in 2000 years or so when archeologists find it they will get headaches trying to figure out what it is and how it is supposed to work. Make sure that you engrave your name on it so that you will forever be recorded in history.

By the way it is a great piece of work.

 

Edited By norman valentine on 26/10/2016 16:27:00

[Neil WyattModerator @neilwyatt]

Thanks Norman, here's the moon phase dial:

The uneveness is down to the etch, not bad painting (for once!) the black is actually several layers of black sharpie then a windsor and newton gloss spray for all surfaces including metal. Works much better and smoother than cellulose and removable with white spirit.

Neil

Edited By Neil Wyatt on 26/10/2016 17:30:26

[Neil WyattModerator @neilwyatt]

Phew!

26, 28, 29 (x2), 30 (x3), 33, 57, 59, and 48-T gears cut today and last night.

All that's left is 45-T and a bunch of 12-T that I can cut as a 'stick'.

But drinking a Cab Sauv for South Africa ('The Cheetah Reserve&#39, far too nice and smooth for its price, and better than the Aussie CS that preceded it I'm afraid. So not a good idea to cut any more gears tonight

I can then finalise all the gear spacings on the bottom plate and redraw the top plate to suit actual, not theoretical locations.

Th washers came too, seem to be good quality that i can use straight from the packet. As hoped the M3 washers are an easy fit on 1/8", in fact slightly more clearance than expected (which is good). Thinking I need some graphite as dry lube will be best for something with parts that rotate as slowly as once every eleven.8 years…

Neil

[Dave GoodchildParticipant @davegoodchild71437]

I've only just been pointed in the direction of this forum and your thread. I'm really impressed work your gear work for this project of yours – a jovilabe makes a nice change from a traditional orrery – and from an historical point of view until the invention of accurate sea going clocks by the great Mr Harrison in the mid 1700's knowing the exact position of the moons around Venus was the only way of pinpointing your longitude as you sailed around the world – not an ideal navigational solution, but it worked!
Anyhow, apart from telling you how good this is looking so far I just wanted to defend the honour of the Antikythera Mechanism that you mention a couple of times – I'm not sure how much complexity your machine will have eventually, but the Antikythera really is a complex old beasty. It has several differential drives with pin and slot gearing, bits spinning within other bits, retrograde motion outputs for the five naked eye visible planets (pointers change direction from forwards to backwards and vice versa), accurate eclipse prediction capabilities, moon phase indicator, and of course there are the two big spiral slotted date dials.
I know all this as I've just spent the past two years or so building one… out of wood… Sorry, unfortunately I don't yet have a lathe in my life, or the skill to use one.
Anyhow, there are a few photo links below to show you what I've come up with – and so far it works beautifully… I just hope that my luck holds until the end.
There is still a fair bit to do before it's finished, but the mechanism itself is all done. The most difficult task will be calibrating it.
Keep up the great work, I shall be watching with interest and wishing that I had your fabrication skills!
 

Edited By JasonB on 11/12/2016 20:58:43

[SillyOldDufferModerator @sillyoldduffer]

Wow that's good! Thanks for letting us see what you've done.

Dave

[Clive HartlandParticipant @clivehartland94829]

Duncan, my gunsmith friend used to engrave/stamp around the muzzle of all the guns he made, 'FECIT' and his name. Which basically means , 'Made by'.

Clive

[MWParticipant @mw27036]

Posted by Dave Goodchild on 11/12/2016 20:40:25:

I've only just been pointed in the direction of this forum and your thread. I'm really impressed work your gear work for this project of yours..
I know all this as I've just spent the past two years or so building one… out of wood… Sorry, unfortunately I don't yet have a lathe in my life, or the skill to use one.

Thanks for choosing to show that to us Dave, It looks incredible, I can see why you opted for wood given how much a metal one would cost! Do you cut and drill all the pieces by hand? if so I don't think you should have any trouble at all with a lathe with the right guidance and dedication. I think you'd surprise yourself just how capable you might well be!

Michael W

[Neil WyattModerator @neilwyatt]

Hello Dave, welcome to thr forum.

I have a fancy your skills are greater than mine!

My comparison with Antikythera is on two points – one they are both almost entirely geared down, unlike a typical clock, which imposes lesser demands on the integrity of the mechanism. Secondly, mine just happens to have more gears and bigger is better

Progress at the moment is slow, I have managed to get almost the whole gearbox working on a test, even though the spindles are supported only at one end. I am just struggling to find the big chunk of time needed to do a good job of the front plate. Hopefully the Christmas break will give me a few days in a row to focus just on that.

Neil

[Dave GoodchildParticipant @davegoodchild71437]

Ah, yes, needing more time – I can totally sympathise with that. This is exactly the reason why mine has taken two years to build so far!
It looks like our gear counts are going to be similar – the mechanism accounts for 54 gears, and the winding handle assembly will add another five taking the total to 59, with a tooth count approaching 3500. I was dreaming gear wheels at one point…
I’m also thinking about the front and rear plate decorations (I have output dials on both) , this stage is almost the final hurdle but it has to look right or it could ruin the look of the entire machine. I’m also going for a bit of spare Christmas time to have a play.
Anyhow, I shan’t hijack your post any longer, but I’ll look forward to seeing more updates.

[IMG]http://i1295.photobucket.com/albums/b629/minimoa12/20160913_205357_zpszcyaccqt.jpg[/IMG]

Edited By Dave Goodchild on 12/12/2016 13:48:42

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