It’s finally time for the big reveal.  But first an aside on the final assembly.

This was an exciting time.  I probably got a bit too excited about it actually; I probably should have taken my blood pressure at some point.

Copernican Planetary Orrery

I had all the parts on hand and I just had to glue some things together and drill some pilot holes.  The crank plate is screwed to the base as are the support posts at the other end.  I drilled these by hand and had no issues.  I discovered upon mounting the crank plate that the hole for the crank shaft was about 1/8″ too high and the pegs of the crank lantern gear did not even touch the pegs of the Mars gear.   Doh!  I’m still not sure how that happened after thinking about it a lot.

I had some pine left over from that very part so I just cut and drilled another.  My first attempt also had an annoying trait: the brad point bit that I bought was oversized.  This was quite annoying but the crank shaft wobbled a lot in its hole.  I went for another bit to make my second crank plate and this one worked much better.  Plus, the hole was actually in the right place.  Once again, I was struck by the precision that is required when you need gears to mesh.  Many woodworking projects can deal with some slop and if things don’t fit you can beat them with a hammer until they do but when you have a gear train, things better be right in the beginning or they won’t work at all.

After this little hiccup, I went ahead without any issues.  The “drive” gears, i.e., the ones that the crank connects with, are all connected together and rotate as a unit.  I glued these first.  The “planet gears” (the rest of them) rotate independently.  These have the tubular shafts connected to them and they are actually a press fit.  The holes and inside diameters just match and with a bit of force, they fit together without glue.  I guess time and humidity changes will tell whether that is good over the long term or not. If they loosen over time I can probably drip some low viscosity CA glue into the joints and take care that.

Side View

Anyway, I then put the top on and put on the planets.  It was as simple as that.  The planet holders are also a press fit although (as I previously wrote) one of them ended up a bit large due to an oversight on my part so I had to put a piece of tape onto the shaft to make it bigger.  But after that, I gave a turn on the crank and the whole thing came to life.

It was the coolest thing ever.

The peg gears need a bit of tuning up; the whole thing will go like butter for a few cranks and then stall out as one of the pegs ends up not-quite-right.  I suppose this is to be expected.  CNC precision is not the answer to everything.

But it’s done.  Almost.  I still need to print the dial onto some cool-looking paper and stick it onto the top.  And then it’s finished.

Top View

This was a fun project indeed although it serves no useful purpose unlike most woodworking projects.  But it’s super fun to turn that crank.  I should sell tickets.

Here is a link to a flickr set of all my photos of this project. I’m working on a video too but that’s going to come a lot later.

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