DIY Moon Phase Dial

[Gina]

I'm now looking at a new casing for the clock.  I need to sort out how to attach the sides, top and bottom to the picture frame.  This appears to be some sort of wood covered with matt black plastic sheet so maybe I could peel this back from the back of the frame and just glue 6mm plywood to it - edge of ply to flat back of frame.  OTOH with the frame being 18mm thick I could cut a rebate into it with my router using a 6mm cutter.  It could take 6mm depth without being weakened too much.

I'm thinking of a 350mm square piece of 6mm plywood to which to attach the gears and motor.  I looked for aluminium sheet but could only find one cut to that size for £20 odd whereas a 400mm square cost about £7.  Sawing 50mm off two sides would not be my idea of fun!

I'll glue blue paper to the square panel and up the sides inside the case.  I have a roll of blue craft paper on order.

[Gina]

This is an interesting looking clock - the first one I've seen with a globe type moon dial.

[Stub Mandrel]

Looks like you've got competition -)

[saac]

Lol my browser opened on the posting of Gina's photograph above - for a brief moment I thought "wow Gina has been busy".  Anyway, pretty as it is Gina is not as good as yours

 

Jim

[Gina]

Thank you Jim

I've been trying to work out how the new case will be constructed.  The picture frame could be attached to a 6mm plywood frame using a groove cut with a 6mm cutter in my router.  But how the rest goes together whilst still allowing it to be taken apart remains to be seen.  One possibility might be to just have a push fit of the plywood in the groove, then the rest could be glued onto the plywood.  With the clockface fastened into the frame with the little clips there's no need for screws into pillars.

Here's a SketchUp model of the frame and 6mm ply as far as the square piece that the gears are attached to.

[saac]

What about holding the clock in the frame by adding some fingers of wood that rotate on a pin - (not explaining this well) the type of thing you get on a standard photo frame.  This type of thing:

 

Jim

 

[Gina]

Plywood panel with gears and motor added.  The back end of the main axle would have a ball bearing and some sort of bracket to support it.  Alternatively, the previous case could be cut down and attached to the panel.  The ply panel would also have a slot cut out for the moon drive ratchet wheel and the whole top part with moon globe would be attached to the top (rear of sketch as shown).

[Gina]

Been working on the moon dial.  Shortened the moon pillar to bring the globe down to the right height.  The drive gears will be in the top inside the dark area but being white will still show a bit so the works will still be visible after all.

[Gina]

I have ideas for the case.  Clock gear train omitted for clarity (and because I can't be bothered to model them - or the teeth on the ratchet wleel ).

[Gina]

More thoughts on the box plus the bottom of the top part.  Moon drive gears not shown.

[Gina]

Made a slight error with the depth so here's a couple of screenshots of ShetchUp with it put right.  I have another idea for fastening the case together - screws into the picture frame inside between the tri-colour LEDS.  I think three would be sufficient.  This will save messing about with the router.

[Gina]

6mm plywood cutting list :-

1. 346mm x 352mm - 1 off
2. 346mm x 26mm - 1 off
3. 358mm x 26mm bevelled both ends - 1 off
4. 358mm x 26mm bevelled one end - 2 off
5. 225mm x 114mm - 1 off

[Gina]

Changed my design for the axle and bearing for the ratchet wheel and gear.  The cylindrical top part of the bearing will go through a hole in the top base plate.

[Gina]

 Another little part printed.

[Gina]

The roll of craft paper came today - rather a different blue from the card but propably alright.  Paper at top card at bottom.

[Ajohn]

I was thinking in terms of using a shelf going back into the case to support the horizontal gears Gina. Backing paper running down from that an also in the "pocket" formed by the shelf leaving all of the gearing visible. I suggested making the clock face a bit smaller to get round the lack of visibility in the area you indicated with arrow  A. That might mean changes to the size of the case or it might not. As it's a visual thing hard to say. The shelf gets around having a slot and leaves everything visible.

 

 I'm no artist though. Just a humble engineer.

Mmmm you would have to support the prawl from the top of the case. Maybe something printed ?

John

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[Gina]

Thank you John   I see what you mean.  In fact in a way I'm going for something not that different except that the shelf will be the top of the square box with the horizontal spur gears above.  They will still be visible but your idea of a shelf might still be a goer placed above the spur gears and below the moon globe.  Then the gears could be lit.  Interesting idea - thank you

[Gina]

Cut the back panel, drilled and cut holes and attached some of the parts.

Front.  This will have blue paper stuck to it unless I decide the wood finish looks nicer

Back.

Front with frame and clock face placed on top.

[Gina]

Here's a better photo of the clock with it's front on.  Also, I've moved the gears and moon globe up a bit.  Adjusting the globe height is easy with the new case.

[Gina]

Motor mounted.

[Gina]

Now printing the bracket that will hold the ball bearing on the back end of the main axle.

[Gina]

Photo showing stepper motor and main axle back bearing bracket and housing fitted.  Gearing seems to move freely but we'll see when the motor is powered.

[Gina]

There is a lot of play in the intermediate wheels on the axle which allows contact on surfaces which aren't meant to contact each other but this isn't too bad with the clock in it's normal orientation.  But I'm thinking of adding ball bearings instead of plain bearings with ABS on stainless steel (not polished - just plain bolt shank).  This would both hold the gears straight and reduce friction.  It also elininates the wear with plain bearings which has certainly occurred to date.

[Gina]

Been printing new gears to take ball bearings - photos tomorrow (probably).

[Gina]

Printed gears and bearing for the minutes to hours intermediate wheel.