Designing an orrery with my nephew

I hinted in my last post that I will be working on a new orrery that we can make in small batches.
I decided that this would also be the perfect project on which to bring in my nephew Harry as he has shown a keen interested and he can add to the skills that he has already learnt in the workshop. We are self-isolated together so why not mix things up a bit. It is also a good way to learn how to apply maths in everyday situation which is great as he will be entering into the first years of his GCSE in September, virus willing.

Above left is a prototype from 3 years ago. Only the gear train, base and the legs were completed. We will use this model to help us with the scaling of the orrery. The orrery will be scaled down so that the base diameter is approximately 7 inches. So proportions will be important.

The design will be themed on traditional orreries circa early 19th century. The photo above illustrates the style of the time. There will be six planets, Mercury to Saturn and no orbiting moons. I have not decided yet whether to turn the planets from steel or brass however there are some less common materials I will be trying out, so we will have to wait and see on that one.

The brass base will be engraved with the months and zodiac and I also want to get creative with illustrations that will suit the time period.

We will only be working on this project one day a week and I will document each day that we do.

Today after a quick briefing I had harry dismantle the gear train to count the teeth and work out their dimensions. The drawings for what I had completed so far where only scribbled down in draft form and had been lost so it was a case of retracing steps.​

​Once completed I had Harry practise on the lathe turning plastic discs these will be for a fixture for some work we will be completing on the mill. He done an outstanding job in machining the faces and bring them to size. Bravo.

That was it for today. A bit of practising for Harry and knocking about of ideas. I will get some technical drawings complete during the week to kick start the project. Please check back in with us next weekend.