Astro Skeleton clock.

[kvom]

With so many gears of different sizes, do you have to make your own cutters? How important is tooth form with really small gears?

 

[Buchanan]

Kvom : I have a large set I bought and have added to from to time to time. All from Thorntons in England. I have made my own single tooth fly cutters over the years but if you want a beautiful smooth transmission then I cannot beat a bought cutter. In clock making , smooth torque is some times more important than constant angular velocity. This applies to the oscillator drive train as well as to the strike and chime train as variations in torque can cause variations in strike speed which can be noticeable to the ear.
Buchanan

 

[Buchanan]

There is a new instalment on the clock at my client’s website.: http://www.my-time-machines.net/astro_06-17.htm

Here is something that might be of interest.

I CNC milled a pretty brass Sun face for the dial that I am working on. I needed to fix it to a steel arm to make it into a clock hand. Now the Sun is a little over 1mm thick. I don’t like solder or glue so riveting or screws was the way to go. Riveting is to permanent, I may want to gold plate the sun but not the steel arm. Now the question was, where do I put the screw? One screw behind the nose where the sun is the thickest won’t stop the Sun spinning around. I needed locating pins or two screws. The Sun is all brass and I thought it might look better with a little colour. Blue eyes would be good.

So I drilled his eyes out and tapped the eye sockets 0.5 mm by 0.125 mm pitch and made two screws countersunk 0.8 mm diameter in the steel section. The tips of the screw are long enough to form a new eye. When they are heat blued we have a blue eyed Sun that is securely held to the steel arm. You might notice the little jig that I use to slot the screw head. It consists of a collet with two hard pins each side. I piercing saw is used to cut the slot, the blade is placed diagonally between the two hardened pins and the swung around to keep the blade against the pins. This holds the blade central over the screw head while the slot is cut. It was given to me by Mr. Drabsch from Canberra who invented it.

If any body can make good brass flames to go around the sun I would be very glad to know how to do it.
Buchanan

 

[kvom]

I read through the updates and again can't say enough about how cool this is. Could you say that the end is in sight?

 

[Buchanan]

Kvom I think I could say that there is a light at the end of the tunnel....

I have two more major assemblies to make. A Planisphere, which is quite simple. It shows the stars and also the sun's position in the sky, and an Orrery.
This has all the planets up to Saturn with moons for the Earth, Jupiter and Saturn as well as a few of the elliptical orbits and Saturn"s tilt, which will be a complex mechanism. I have a basic gear count and layout for the Orrery that I will copy and tweak to suit our clock but that is about 5% of the work saved.

The there are the dials, hands, bezels weights and case. Then I have to polish everything. Another year should get most of the construction complete.

Buchanan

 

[Buchanan]

We have another month's progress here: http://www.my-time-machines.net/astro_07-17.htm

I have been filing cams for the sunrise and sunset shutters and hands. A slow and painful process.

 

[kvom]

I was wondering about the tool used with your EDM machine. Looks to be copper. I had been under the impression that these were graphite.

As always, your work is awe inspiring.

 

[Sansspaceship]

Amazing work, to have a mind that can visualise and build that detail is incredible!

I think even one of those modules would turn my brain inside out, if I even started to try and think how you would design it in any detail. Add the art of the design on top and you have an incredible time piece!

I have a dear friend of mine who did a complete restore on a WWII Corsair which was I think a 10 year build, and kudos needs to also be given to the patrons of these projects as the also have incredible vision as well.

Thank you for sharing.

 

[Buchanan]

Kvom.

The electrode is copper, correct, you can use any conductible material as an electrode. The four factors that make a good electrode are low electrical resistance, high melting point, good machining, and price. I know that jewelers will use silver as an electrode. Gold would be better but price may be a problem. Each type of electrode material has different wear rates and needs different types of electrical pulses to be effective. I have a larger EDM Machine that is specifically designed for copper and it will not spark with graphite. I have used tungsten Carbide inserts to spark their own pocket for turning tools. They don't have good electrical properties but a stupidly high melting point. Machineability is also an issue with tungsten carbide!!

 

[bazmak]

Many years ago i used to be a good dart player when copper/tungsten darts
became affordable.Later of course nickel and silver tungsten to replace brass
Mainly for the SG of tungsten to produce smaller heavier darts.As a sheetmetal
worker i used a resistance spot welding machine and was forever replacing or grinding the copper tips. I did try bracing a small piece of a 6mm dia copper
tungsten dart to the main tip.This elongated the life of the tip and maintained
a cross section area of spotweld. Tungsten alloy darts are now so cheap and readily available. Would these matls properties of weight and high melting point
be of any use ? and easy to machine

 

[Buchanan]

Yes, I have used Berrilium copper(Dangerous in dust form) and Tungsten copper. The best electrode material I have used is ,to my knowledge Tellurium Copper. It is the best material for copper based electrodes.: Quote: Tellurium Copper's (TelCu) resistance to hydrogen embrittlement combined with its' high electrical and thermal conductivity make it the ideal choice for electrical applications requiring extensive machining, corrosion resistance, or for the production of hot forged products.
The cutting properties of copper are enhanced significantly by creating a copper alloy with the addition of .5% tellurium (C145 Tellurium) which is adapted for use in high-speed automatic screw machines. On a machinability rating scale with 100% equal to free-cutting brass, Copper 145 Tellurium has a machinability rating scale of 85-90%, compared to pure copper which has a machinability rating scale of approximately 20%. The results? Increased efficiency on manual and automatic production lines as well as a significantly longer tool life!

It is a very nice material to machine compared to normal copper and does not cost much more. It is also available in larger sections. Graphite kicks in when you want large electrodes.

 

[Buchanan]

This web page and the videos on it gives a very good overview of the clock. http://www.my-time-machines.net/astro_10-16.htm

 

[kadora]

Buchanan your clock looks like gearwheel heaven.
All wheels connected and unisono working //communicating?// together.
This masterpiece probably has its own consciousness.

 

[Buchanan]

Here is another update. http://www.my-time-machines.net/astro_08-17.htm

 

[kvom]

I just got back from 3 weeks in Japan just in time for another update. :thumbup:

One thing I learned from a museum exhibit was that the Japanese had their own type of clock that makes for an "interesting" complication. They divided up a calendar day into two periods, day and night, and each was divided into 6 equal parts. Since day and night periods vary daily, it seems quite tricky for a mechanical clock (Wadokei) to handle it. But they did.

 

[kadora]

BUCHANAN I am speechless again.
How did you paint arabic numbers on dial ? Is it enamel ?
How will you transport this mechanical computer to your customer?
How many kilograms will be the weight of completed astro clock?
Are fully running astro clock noisy?
Sorry for my naive questions but I have never seen such complicated machine
in my life.

 

[Buchanan]

The Arabic numbers are drawn by hand 2 or 3 times oversize and reduced on to paper as you see here. When we are happy we send it to an enamel dial maker and they are done in traditional fired enamel. The construction is modular, so we can pack the small delicate parts separate , Transport and packing is a nightmare. The whole clock mechanism weighs about 60 KG but the weight and case will bring it to about 200 KG. To maintain so much movement for a week takes a lot of watts and that must come from somewhere. the clock is actually quieter than a grandfather clock because the escapement is a grasshopper and that does not tick loudly,when it strikes it makes a little more noise but not very loud as the clock is for a house. Questions are welcome and thanks for the compliments.
http://www.my-time-machines.net/astro_05-13.htm and the next few pages shows the enamel dials being made.

 

[Buchanan]

Here is another update. http://www.my-time-machines.net/astro_09-17.htm

This section of the clock is now almost complete. The attached photos show how I made the Moon. The materials are Mammoth ivory and ebony. I am not sure how old the mammoth is, but the ebony comes from a round ruler used at school, for ruling lines on writing paper, over a hundred years ago in South Africa. Both should be reasonably stable. Now if we want a multi part object to remain intact for a few hundred years we cannot rely on glue alone, so, I held each section together with an internal brass ring. These sections are again held captive by the numbered rind and held together end wise by a screw. Both Mammoth and ebony are most delightful materials to work with and the color contrast is lovely. i enjoyed the bi colored swaff. I believe a good engineering design has a few parts possible. I have failed miserably in this connection with this clock. This Sun Moon mechanism has about 550 parts, including screws , bearings and taper pins.

 

[bazmak]

UNBELIVEABLE I have seen some awesome and beautiful engineering in
my long lifetime but nothing as awesome as this. THANK YOU FOR POSTING
Regards Barry apprentice in many trades but master of non. I would call you master

 

[Rickl]

That is magnificent. What skills to do all that. Congratulations.