The Mary Chambers model was the first of the models in the Archive Project that we completed. As parts of the process of mounting the puppetry onto a plinth I wanted to update the mechanism so that the style matched that of the later projects.
There are three main movements in this model. The soldier rows the boat, the boat rocks up and down and the waves… well they wave. All three movements can be based round a circular crank movement but they are all at different speeds. Fastest moving are the waves with the rocking of the boat slightly slower. The rowing movement is slowest. Slow and steady. I laid out this gear train which should so the job.Time to transfer it to the real world.
I made a simple jig onto which I can build the gears.This keeps everything at right angles and makes sure that the key slots are aligned.These pictures show the largest gear, the thirty seven tooth gear, being constructed. The gears are made up from three layers of laser cut ply . The gear part with the spokes is sandwiched between two disks and fitted onto the jig until the glue is dry.
With the gear centre removed from the jig I fit the outer tooth rings into place front and back and clamp them into position whilst the glue dries. You can see the short section of rack in the picture that I use to make sure that the teeth are lined up properly.
The finished gear.
I’ve then constructed an arch to hold all the parts into position. Here you see the assembled parts, almost complete apart from the keys which will be fitted to the axles.
Finally! It’s taken me weeks and weeks of experimentation and development but today I finally finished my first laser cut automata for the Archive Project. The Archive, as its name suggests, is Cumbria’s repository of all the county’s historical documents. I’m hoping to supply them with a series of plinth mounted automata to embellish the public areas of the building. The first model is of Mary Chambers, I’ll fill in the historical details in a later post but suffice to say, Mary was transported to Australia for a variety of petty crimes.
At the heart of the model are these three gears They are made up from three layers of 3mm thick laser cut ply cut ont my HPCLaser laser cutter. I’ve opted for quite large teeth with fifteen millimetre pitch. The larger teeth will be stronger and the larger size will hopefully mask any small inaccuracies in cutting and assembly.
Once all the parts were designed and cut I started the process of putting everything together. As is often the case new ideas and things-I -could-do-better-next-time cropped up all the way through the process. The model is designed to be taken apart for maintenance. I’m using brass tubing for axles with the various parts being fixed to the axles using drilled holes and split pins. This will be one of the first things I change for upcoming models. The holes are awkward to align making it difficult to fit the pins. Perhaps a brass collar fitted with a rub screw next time? The gears fit down the inside of the box in their own little section. The centre gear is the driven one. It will be turned via a toothed belt and an electric motor.
The front axle is connected to a small-throw crank. This is used to lift the boat gently up and down. On either end of this axle are the animated waves, again driven by cranks.
The axle at the other end of the boat is geared down with a twenty seven tooth gear. In turn this is connected to this crank. The crank push rod is then threaded up through a hole in the boat base and connected to the ends of the oars by a couple of flexible straps.
With all the parts put together it’s more than gratifying that it worked smoothly, and with just the motion I was aiming for. Phew!
This morning I took the mechanism round to Archive and Dawn H and I fitted the puppets she has made into place. It worked fantastically, the nameless rower really puts his back into the rowing motion and poor Mary rocks back and forth dolefully in the front of the boat. I can’t wait to get started on the next one!