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Orrery, continue inner planets gearbox  - February 2019



Buchanan writes: I recut the teeth deeper in the two offending gears and all is well. I had to make special support washers as the wheels were spoked.

I have the drive from the centre input, down through the plate and around the Jupiter arm drive wheel, onto the moon drive, for Saturn and Jupiter to the point where I have to spoke two more wheels and screw three to their collets. Then I have to fine tune the height of various gears and drop the Jupiter orbit dial a little and shorten the collet on one of the Jupiter arm idler wheels.

After that when the clock is demo’d the Jupiter and Saturn moons will revolve.

Oops! We have a conflict between the Jupiter orbital dial bezel and gear mounted to another rotating arm. Notice how the wheel not only touches the bezel but is also knocked out of mesh with its mating wheel opposite. With the clearances so tight and the wheels being only 0.5 mm thick, these become serious issues.


The first photo shows the problem from above. The clearances are now corrected, second photo.


Buchanan writes: I have the next two bearings fitted. These are for dumb arbours for the upper input drive, (White pair of horizontal arrows, first photo). The reason I decided to use this type of bearing, is that, my other option was a cock. This meant that I needed space above the upper gear for a bearing and cock. There was no free space for an upper bearing and cock, if I used a cock, it would push up the height of the whole gearbox.

These bearings project down below the lower frame into dead space. I have clawed back another millimetre by doing this. When combined with tucking the 32/77 gears below the 12/106 gears means that I am almost back to where we wanted to be. I am pleased. Here again we see constant issue of vertical height constrictions being fought out at every turn.

We also get more exposed gears as there are two less cocks to get in the way. These gears are also very close to the frames so there is very little cantilever force on them. The rest of the outer gears will have beautiful jewel bearings...

(Photos three and four) are the bottom and top of the lower frame with the next two bearings and housings fitted. We very nearly have a clearance issue with the smaller gear but all is well, (vertical white arrows, first photo). You can see that I have all the outer wheel pivots drilled as pilot holes (white circles), as well as the 4 pillar holes, (white squares, second photo). It will be fun to work a frame design into this one.



Buchanan writes: The next arbour is complete and the third is halfway there. (first photo), some spoking of a small 32 tooth gear. Look at how tiny this component is compared to Buchanan's hands and even at this scale he makes a six spoke wheel!

You can see (in the fourth photo) that I have tucked the solid gear under the other. So we save the sum of height of a gears thickness and one clearance space between gears. Then there is no cock bearing to worry about as well. I will explain this issue when I mount the top plate and its cone of gears.

I am aiming to complete this gear train by tomorrow. Then it will be on to the last 4 arbours between the frames. These have clutches between each set of gears for the planet setting.



Buchanan writes: (First and second photos) are spokeless, toothless gears. A high speed test run, driven from the mercury end of the train with a screwdriver. I have the drive through to mercury now. The last gear in the upper cone, the smallest gear, Mercury’s input is now mounted, (third photo). Side elevation of this assembly, fourth photo.



Buchanan writes: Yesterday I spent thinning down the height of 8 jewels for the side arbours (first photo). The reason for this is that I wanted to use our large jewels but the plates are thinner than the jewels. In the second photo the thinned jewels are shown next to the one unaltered jewel to the right. We will later see just how stunning this looks in the final presentation.

I have the first two arbours complete and the collets pressed on, as well as the hardened pivots pressed in. I also have the first arbour between the plates for a test fit in plain drilled hole bearings. If all is well I will fit the jewels in a single session (second photo).


Buchanan writes: Today was not such a good day.

I had a little tightness between two gears, so I thought I would cut the teeth a little deeper. I set everything up in the milling machine, but set the depth of cut off the bottom of the tooth instead of the outer diameter. When I switched on the mill, it cut two teeth before I stopped it, as it sounded like it was removing too much metal.

You can see the results, (first photo, damaged and repaired wheels). Three hours later, I have made two more gears, (second photo). It could not be done quicker. The mill was set up for cutting the teeth. I had material semi prepared. All the lathes had the correct tools in them.


This is the jig I use for cutting slots in screw heads, when I only make one or two special sizes (first and second photos). The saw is twisted around the keep the blade against the guide pins and that keeps the blade perfectly centred on the screw head. One of those simple tools that work extraordinarily well. This setup has been seen before. For making a batch of screws Buchanan has made videos in November of 2013 of a small lathe setup with a multi-tooled turret head to make an entire screw in about 60 seconds. 



Buchanan writes: Stainless steel sleeve to go over the blued steel centre (first photo). The arbour is too short to press in such a thick lower pivot. (Second photo) is the finished arbour.  You can see the steel pinion at 11 o clock on the right plate (see photo below). A word here about why Buchanan has done this. At the beginning of this project it was decided to have all of the wheel arbors and pinions made from stainless steel to avoid any future corrosion. However, stainless steel does not have the qualities needed for the pivot ends, it is not hard enough and has on a molecular level “sticky” attributes. To make this concept work, all of the stainless arbors had their ends drilled to accept hardened steel pivots. In this example the arbor that the pinion was to be mounted was too thin to accept a drilled center and tool steel insert. The solution was to make the entire arbor from tool steel and cover that part with a stainless steel cylinder around the portion that will be exposed between the pinion and the opposite plate. This is another example of where high standards are applied even if it takes a bit more effort.   

I had to crank my old gear cutting mill to cut the 10 tooth pinion in stainless steel for the final drive to the Jupiter arm.  The CNC just can’t slow down its cutter speed enough, (third photo and finished assembly in fourth photo).

I also have the preliminary paper drawings prepared for the frame design. My mother is booked in for Monday. I cannot assemble the gearbox until the frames are fretted out. Buchanan's mother has designed all of the scroll / ivy artwork on this project.

I am trying to get the Jupiter arm clutch completed this afternoon. There is also the jewelling to complete and the arm clutches to finalize before I can move on the planet arms and the last of the gear cutting.

I have all the wheels mounted in the centre gearbox between and below the plates, 41 gears here! Here we have an open sandwich of the inner planets gearbox showing two very different configurations on each side. On the left an orderly concentric set of wheels, on the right a scatter set, yet they all will mesh perfectly! This photo boggles the mind of someone who is not conversant with the methods used in the construction of this project. I thought it to be a very instructive photo.

Here the concentric gear set is set within the mating gear set on the lower plate.

The inner planets gearbox is mechanically complete. The parts count so far is 174, but there are still the planetary arms and the associated gearing to produce the eccentric orbits of Mercury and Mars. Venus has a nearly circular orbit as does the Earth.


These two photos show the top frame design.


The three drawings above illustrate the evolution of the design for the lower inner planets gearbox frame. Buchanan's mother develops these as she has for the entire project. This will be the last set of drawings needed to create a frame design for this project.

The lower frame design is cut out from paper and checked for fit on the extant set of wheels that are currently located below the inner planets gearbox.

The final design is glued with a spray adhesive to the brass blanks for the upper and lower frames.


In the first photo one can see where the pillars have been moved from their initial locations, red, to their new positions, blue, in order to reduce the size of the frame assembly allowing for more exposure of the wheels. In the next photo a paper cutout of the frame is overlaid to give the viewer an idea of how the frame will relate to the wheel works.


These two photos show the process of transferring the frame design from a paper concept to reality in metal. Here is where artistry  meets artisanship. Here is shown the scribing of the design onto the metal and the removal of the paper template.



The first photo shows the scribed design on the two plates representing the upper and lower inner planets frames. The second through fourth photos show the process of cutting out the lower frame on the jeweler’s scroll saw. Notice in the last photo how the entire complex shape of the frame is cut out in one pass of the saw. Buchanan does not approach the work in segments or sectors to cut those sections separately, but does the entire complex shape in one elegant procedure. See another example of this technique from November of 2008.


The first photo shows the hand finishing needed after the frame is cut out of the blank using filing buttons to perfect the curves as well as many different grades of hand files for the rest of the curvilinear profile of the frame. The second photo shows the completed lower frame positioned onto the cone of gears that will comprise about half of those within the inner planets gearbox. This final framing out where a blocky brass blank is turned into a beautiful part and the assembly is rendered beautiful is Buchanan's favorite part of the process and it shows!

The completed frames with their associated wheel assemblies; left is the lower section with that on the right the upper section. Notice how the placement of the jewel bearings brings a pop of color to the module. Seems hard to believe that these two components will sandwich together to mesh perfectly.

Top view of the inner planets gearbox assembled. Everything fits!

Bottom view of the inner gearbox assembled.

The diminutive size comports with the scale of all of the other behind-the-dial wheel works components comprising the other complications within the clock.

An initial demonstration of the wheel set for the inner planets gearbox of the orrery. This will display the orbits of Mercury, Venus, the Earth/Moon system and Mars as well as the rotation of the Sun.

The inner planets gearbox mounted within the orrery dial ring and set upon the rest of the machine.

The orrery is nearly complete and is positioned within the rest of the machine and the orrery dial ring.

An upper left three quarter elevation of the assembly within the context of the machine as a whole. While the orrery is a beautifully complex assembly it is only one of many complimentary components that make up this beautiful example of kinetic mechanical art.

Buchanan writes: If a spaghetti factory made gears-------It would look like this. Agreed!

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