Having a job to shift this cold and still not up to doing much which is making me feel depressed.  It's better than it was but still have a bad cough and just can't manage much

Looking at thingiverse the other day I came across an illuminated moon globe that looked just the thing for the moon phase globe for this clock.  It's 140mm diameter with craters etc.  This would be a bit bigger than the moon in my moon phase clock which is 100mm diameter and should suit the bigger clock.  Glowing Moon  Worth a try, I think.  Probably try natural or white PETG or ABS.  It would be nice to have a moon globe with a bit of detail on the surface if I can get it to work

My Mini printer is working well and seems accurate enough for the escape wheel so when I have finished a couple of higher priority projects I hope to get back to this one

Been trying to print the moon globe and successfully printed the base part in PLA though it took quite a long time.  The main globe is another matter - the gcode file is 73MB even for half the globe which is all I require for this clock and will take an estimated over 24 hours to print.  However it's printed it needs lots of support.  Also, although the bottom part printed fine, the top is having a problem sticking to the glass bed.  I have some PEI on order which may be better but this print will use many times as much filament for support as for the wanted part and with such a rough surface of the moon, there may be a problem breaking the support away from the wanted part.  So whilst it would be great to have a realistic moon phase display it hardly seems practical.

Long case clock with glowing moon phase globe would have been awesome ........ Hand designed and printed long case clock without globe will still be awesome! 

I've left the print running just to see what happens and it's now on layer 4 and the printing time estimate is around 33 hours.  There are things I could try, such as using a type of filament that can have a greater overhang before it needs support such as PETG.

13 minutes ago, melsmore said:

Long case clock with glowing moon phase globe would have been awesome ........ Hand designed and printed long case clock without globe will still be awesome! 

Thanks   I can have a glowing moon phase globe without the crater detail like I have in my wall clock with moon phase globe dial but the difference in transparency due to the way it has to be printed does not make for an entirely natural looking moon.  Crater detail should overcome that as well as looking like the real moon.  I'm prepared to spend a little time experimenting to see if I can accomplish this.

On layer 6 now and the estimated time has come down to around 30 hours.  I think that's probably as far as I'm going with this test.

Tried on my Titan printer which is much faster and has a bigger nozzle and printing time for PETG is estimated as just under 5 hours which is quite practical

The Titan has not been upgraded to Duet control board yet and uploading the gcode takes over an hour!  On the Mini with Duet the upload only took a few minutes even though the file was quite a lot bigger.  I have PETG printing well on the Mini so I'm giving it a go.  It's up to layer 32 so far and been running for just over an hour.  Estimated time left is around 8 hours ATM but as it gets up to the smaller sizes it should get faster.

Going well Been going 2 hours now and probably 7 left though may well be less. 

Over 4 hours now and still fine.  ETA looks like around 1am tomorrow morning but we'll see.  Now seeing some definite surface structure.

More pics as print progressed.

This globe has been printed in natural transparent PETG and I think it's too transparent to show the surface features so I plan to print it in a different filament.  Something more opaque such as white PLA or ABS.  It seemed that a transparent material was the way to go but in reality, it wasn't

Here it is with light shining through from behind.  I have increased the contrast of the photo to bring out the texture.

Earth Date 2018-09-05 - Looking at this project again having got fed up with 3D printer development, which has not been going as well as I would like.

My Titan printer is working well (for the most part) and so is the Mini so I have production 3D printers in operation for making parts.  The main thing now is trying to work out where I got to and finding the parts already made. 

Found some gears that seem to pretty much match this diagram though the escape wheel is off-centre and will need reprinting.

Next I need to find the parts to make up the frame to hold the axles for the gears.  Bearings for the escape wheel and probably the gear that drives it can be PTFE.  The bearing for the anchor escapement could also be PTFE but I think I would favour a knife edge instead, for even less friction.  I might reprint the gear that drives the escape wheel in Nylon for reduced friction.  The pendulum is suspended on a spring steel strip as usual so little friction there.

Had another go at the moon globe, this time with white PLA and it looks very much better.  I think this may  work.

Heres a photo after printing a 20mm high test.  Taken with early morning sunshine for illumination.  This is actually white PLA so why it looks brown I don't know.  May be better with a cold white LED.

Printed a test moon globe - here are a couple of photos with a warm white LED bulb inside.  The clock can have a cold white LED or maybe a combination of white and blue LEDs to improve the colour.  This is with a 0.3mm layer height but I may reduce it for the proper print.  I shall only need the front half for the clock as we never see the far side of the moon so might get away with something like 12-16 hours printing time.  This was 16 hours for the full globe (except the bottom bit).

I've been looking at where all the gears etc. will fit in, bearing in mind that the chain and weights have to go inside the trunk of the clock.  It's going to be quite a tight fit particularly if I'm going to include a striking mechanism.  Looks like chimes are going to be impractical.  The difference between my clock and standard longcase clocks is that my gears are going side by side rather than one behind another and also being a lot bigger.  Big gears make more of a statement as well as being more practical to 3D print. 

The main problem is the large minutes wheel with its 80 teeth and about 200mm diameter.  An alternative would be to change the gear ratios round with 6:1 and 10:1 rather than the other way round.  Since the intermediate gear will need redesigning anyway I can go for 10 teeth and 60 teeth on the minutes wheel, making it 150mm diameter.  The problem with this is that the intermediate gear couldn't be larger than 150mm, making the pinion on the escape wheel just 15mm diameter, which is very small.  I'm going to have to have a good think about this.

Changing the gear ratios round isn't the answer - too many problems.  Reducing the modulus also reduces gear size, reducing the tooth size and keeping the number of teeth.  Going from mod 2.5 to mod 2 would reduce the gear sizes to 160mm and 120mm for the large gears and 16mm and 20mm approx. for the pinions.  That's 80% but maybe 90% would be sufficient giving gear sizes of 180mm and 135mm, pinions of 18mm and 22.5mm.  Mod 2.25.

Having given this more thought I am satisfied that reducing the gears to 90% of original size is well worth a try.  I can do this in Slic3r without having to redesign the gears except for the escape wheel which will need redesigning because I want to retain the 100mm diameter to match up with the already made anchor escapement.

I have the two acrylic sheets for the new design so can shortly drill holes and add bearings ready for testing once the new gears are printed.  I can test the running without the auto-rewind mechanism with just chain and weight.  The problem before was that the escape wheel was not concentric with its axle which was the fault of an earlier 3D printer - now replaced.

Following jobs are to design the auto-winding gear train and drive to the moon globe dial plus a striking mechanism.  Also on my mind is some way of providing auto-regulation of the clock timing.  Having had experience of control systems I think I can probably devise a control system to accomplish this, taking the timing from a Real Time Clock chip (already controlling a stepper motor via Arduino for the auto-winding).  I'm thinking in terms of a two stage arrangement with first stage getting the timing almost right and then the second employing a Phase Lock Loop to synchronise the pendulum with the RTC.

A standard longcase clock is regulated by turning a threaded thumbwheel on the end of the pendulum rod to raise or lower the bob.  The top is suspended by a strip of spring steel held in a slot and another way of regulating the clock is by lifting the spring in the slot and changing the pendulum length that way.  With this method the slot is fixed but the suspension point is moved up or down.  The suspension point can be on the end of a lever which is controlled by a stepper motor and threaded rod.  This means the clock can be regulated from the Arduino.