Intro: Children's Clocks
It all started with our children, we bought them animal clocks that had tails as pendulums and they had great pleasure watching them. When our grandchildren came along we could not find any the same, so - why not make my own versions?
All of the variants are very similar in construction, although I have experimented with different materials and clock movements. All the clocks are really prototypes and could be improved upon if subsequent models were to be made. The children love them and are happy with their appearance. being prototypes, I can create new versions as the grandchildren have new favourite characters. When I started I did not have a workshop of any fancy tools, just a fretsaw, hand drill and glass paper etc.
- The Rag Doll. This was built using 2mm thick MDF, with the skirt being the pendulum, sandwiched between the clock face and the upper body and the legs. Because of the multilayer construction, having to leave space between the moving parts and to build a new pivot, this doll was very sensitive to positioning on the wall.
- Hello Kitty. This was a simple design built using 4mm Polystyrene card with just the legs swinging as the pendulum. This did not require much structural changes to the pendulum movement.
- Moshi Monster. This was built using 4mm Polystyrene card, with the ice cream and book being the pendulum in front of the main body. This required a cage structure to be added to the pendulum, which basically remained unchanged.
- Olaf. The latest creation and the one described in detail in this instructable. This was built using 4mm Polystyrene card and the pendulum mechanism was heavily modified. Even the design changed along the way as I experimented with what could be achieved.
The important thing about this is to have fun and to expand the imagination to match that of the grand children!
Step 1: Planning and Initial Cutting
- The first stage is to research the character requested and to find a drawing or image that you think can be made into a clock.
- Decide on the size, play around with the spacing of the clock and pendulum movements to ensure that they remain hidden. If in doubt make the parts larger than smaller.
- Dissect the drawing into the parts that you will have to cut out. In the case of Olaf, the arms were cut out separately to the body part that they are attached to. By using separate parts the amount of material can be reduced.
- Using carbon paper trace the outline onto the clock material. I have homed in on polystyrene as I had a quantity of 4mm sheet available. I am sure that in the future I shall use different thicknesses if the design dictates it. You need a material that will remain stable and flat. Think of the spacing between the moving pieces. The rag doll used 2mm MDF with 2mm spacing between the parts and I suggest that this is a minimum.
- Cut out the parts with a fret or piercing saw (or a scroll saw if you have one).
- Using a file and glass paper smooth the edges.
- If you are going to paint the surface, use a light glass paper to key the surface of the polystyrene.
Step 2: The Pendulum Movement
I use a quartz clock movement with a separate pendulum adaptor, these are readily available from many suppliers. I chose clock mechanisms that had long shafts, so that I could have several layers between the hands and the movement. For Olaf I had to space the movement back from the clock to get the correct depth.
Before modifying the pendulum mechanism, mount it on a vertical board (I use foam sticky pads) to see how it works, what angles are involved etc. Mark out on the board, or a sheet of paper taped to the board, the positions of al the elements. Mark up the mid way and extreme swing positions. Measure the gap between the pendulum and coil. You will have to rebuild the pendulum getting the static position as close to the original as possible.
For Olaf, the pendulum mechanism was split into sections to make it more compact. In this case I threw the battery compartment and clock surround away. In hind sight, I could have retained the battery compartment instead of going out and buying a new one! (I restate - all these are prototypes and mistakes are made and in some cases I have started from square one again - but that is all part of the fun in creating these clocks)
I have fount that the pivot mechanism that comes with the pendulum cannot be easily beaten, so I retain this and build up a smaller pendulum.
The lower section of the mechanism contains the electronics and coil and must be mounted vertically below the pivot section and horizontal.
When rebuilding the pendulum, the magnet must swing unhindered under the coil with a 1mm gap between the two.
You need to experiment with weights on the pendulum to get the desired swing and frequency, but this can wait until you have constructed the total swinging mechanism.
Step 3: Construction
Use 2mm steel wire to reinforce the arms; children have a tendency to try moving parts that are not supposed to move!
As this is basically a prototype, I use a hot melt glue gun when assembling the parts. During the build of Olaf, I bought a new Bosch gun that was trigger operated, much better and accurate than my old gun which required constant pressure on the glue stick. The advantage of the hot melt glue is that it fills gaps, sets quickly and can stick differing materials.
As a prototype, I have a series of mounts that I use to support the mechanism and structure during its build.
Using double side foam tape I mounted the various pendulum parts on my frame and tested the movement of the centre body and arm section before gluing anything into the main section of the clock. This is a crucial stage to ensure that the moving section is balanced and will return to the centre, with the pendulum magnet exactly under the electronics and coil.
Once I was sure that the pendulum would swing OK I linked the head and main body sections together using a strip of polystyrene.
I then built a bridge section to hold the centre body section in front of the strip holding the main body and head together, make sure that the bridge is wide enough so that when the pendulum is at its extremities, the bridge does not foul with the strip connecting the head and lower body section . This bridge and middle section of the body was then attached to the shortened pendulum.
This completed the first stage.
Using an external battery, I powered up the pendulum and the centre section of the body and the arms swung as I had hoped.
Step 4: Do I Stop There?
I mentioned that these are all prototypes, so the next question is - should this be the final mechanical version.
I decided not!
I removed the feet and created a new section from 2mm polystyrene.
Olafs feet are not symmetrical about the central axis so some balancing will be needed.
Using a nut as a weight I balanced the new extended pendulum to keep the static pendulum central.
This created a new layer, with the feet behind the body and everything swung OK.
I did not like the appearance of this version, so that part was removed, and the next version tried.
Step 5: Do I Stop There - Decisions!
I cut the pendulum and extended it using a bolted section - just in case I want to change it again!
The best decision I made at this point was to use a little hot melt glue to retain the nut behind the pendulum.
Two new feet were made out using part of the original shape, but continuing the shape over the body section.
A new wire base frame was created and glued to the feet. Although I tried to measure and bend the wire in the correct places, it has the advantage over polystyrene that it can be adjusted after the construction to get the position absolutely correct.
I found that it balanced and no extra weights were needed to get the vertical position correct.
In the second picture you can see that I have added two sections of square polystyrene as stand offs so that the whole clock remains upright when screwed to the wall.
I was very happy with the decision to continue changing the prototype, but decided not to go further. You might add, what more could be changed. There are two obvious additions 1. The eyes and 2. the hair. I judged that the pendulum would not take any more strain and left it at this stage.
Step 6: Finishing Off
The outlines, copied onto the polystyrene earlier, were outlined with a pen and the colours added using Acrylic paints.
I draw the clock dial, but there are many that you can download or purchase if you want a classier look.
The hair was sections of pipe cleaner purchased from a hobby shop and attached with hot melt glue.
The final stage was to mount the clock, in this case I had to use some padding between the clock mechanism and the rear of Olaf's body to ensure that the spindle nut fitted correctly.
Attach the hands and you have an Olaf clock.
I hope that you get enjoyment out of making these.