I had one of those flattering but creepy moments this weekend when a got a phone call from someone who had seen one of my projects on the WoodWhisperer website and wanted to know if I would take a commission to make one for him. Somehow, I end up surprised when I put something online and someone actually looks at it.

On the one hand, I’m flattered. On the other hand I’ve never been contacted for a commission before. Kinda threw me for a minute.

FYI, it was an orrery I had made using a CNC router. That’s a mechanical model of the solar system where you can turn a crank and watch the planets move realistically. He was a teacher and wanted one for his astronomy classes.

this is it

This is probably a good place to record the fact that my orrery project made the home page of TheWoodWhisperer.com lately.  It was in the section called “viewer project”.  There was a link to the articles here and my page count went from a dozen or so per day to about 800 per day for two days.

That’s pretty gratifying.

It’s not there any more; they get rotated out about every four days but it can still be found by digging into the archives.

Cool.

I have taken the orrery to work several times (leaving it in the trunk of my car) to show it off and allow people to turn the crank.  As it has endured the temperature and humidity swings, the planet holders (which had fit poorly from the beginning due to my choice to drill the holes by hand) were loose and were prone to non-workage.

As a result, over the weekend I took my corrected CAD models and some wood over to my friend’s house where we remade these pieces.  During the week, I made some now planet mounts and installed the new ones.  SUCCESS!  These fit much tighter.  I think I may indeed have to remove them some day and super-glue them in place but for the moment, they are holding quite nicely.

Unfortunately, one of my gears in the drive gear stack separated from the others again.  DOH!  This has happened several times so far.  I’m not sure what the solution is except to wait until it happens to all of them and reglue them securely.  This time I used super glue since I could squirt that in without taking the whole thing apart again.

It is now on a little table where I can sit down and turn the crank as often as I like.

Things to do to improve the next orrery:
1) Buy better wood.

2) No biscuits when gluing up the wood.

3) Let the machine do the Saturn gear (with smaller bit).

4) Let the machine do the base.

5) Correct the pocket holes on the top.

6) Correct the CAD models of the planet holders and let the machine drill the holes.

7) Let the machine drill the crank plate.

8) Put on finish, then stick on the dial.

9) Try to make the support rods the same wood as the base and top.

10) Make CAD models of the Saturn lantern parts and let the machine do that.

11) Better wire for the planet supports – needs to be stiffer. Lantern gear wire is fine.

12) Didn’t need to polish the shafts – just needed to clean off the price tag gunk.

13) More of an angle on the peg ends.

14) The shaft holes in base and top shouldn’t be through holes – should be blind – will change the shaft length a little.

15) Actually sand it well like you’re supposed to.

16) Check the position of the shaft holes on the base and top – somehow the first one ended up off by a tiny bit which made the gears not level until I stuck a shim on top of the crank plate.

17) Replace crank handle to one that rotates in its socket – makes it easier to turn.

I thought that I needed a nice photo of the orrery.  The ones I had taken were OK but I wanted something more.  Still, it’s a big pain to get an appropriate backdrop, set up lights, etc. but then I realized: when I bought Pinnacle Studio, the box came with a sheet of green screen material to use with the Chroma-Key feature. Well, that’s just what the doctor ordered.

I draped that over a bench in the living room one evening when Mel and Erin were out shopping for prom shoes and then gathered several reading lamps from all over and placed them appropriately.  I put the orrery onto the green screen and snapped away.

I then did some photoshoppage (GIMP actually).  There is a command where you can simply replace one color with another and so when you have a green screen like that you just take out the green and replace it with something much darker to give all the emphasis to the orrery.

Naturally, this did not go perfectly – nothing ever does.  I learned something that all photographers and movie makers already know: that uneven lighting and/or wrinkles and folds in your green screen will cause the resulting image to have not one shade of green but many.  True, they’re all green and I guess the reason that the “green screen” is the outlandish green color that it is is that you almost never encounter that shade of green in normal life.  So in the end, I had to do some extra work to capture all the shades of green that were present but it worked out well anyway.

I did go back and smooth out some wrinkles and even up my lighting to make the color replacement a bit easier.  It also turns out that the orrery itself reflected some green in its surface so that if you replace all the green you end up replacing some of the pixels in the orrery image itself.  In the end I just had to be satisfied with that and not many people notice it.  The image looks way better than the ones where you could see living room stuff in the background and perfection would have taken much longer and probably required more sophisticated equipment. 

Life’s all about balance – you have to decide when something’s good enough.  If you want perfection, you won’t actually get very much done.

My photo looks good.

I made a short video of my orrery.

I had not intended to publish any more blog entries on this but it’s probably worth noting a couple of things. 

First, the plans included a dial that you glue to the top that has months, days, and zodiac signs.  This looks pretty cool so after a lot of fiddling to make it print across four sheets of paper on my printer (surprisingly hard to do – for some reason the CAD program thinks the entire drawing covers 12 standard sheets of paper), I put in some cool-looking parchment patterned paper and printed it out in sections.  I cut these out and used some Type 77 spray adhesive to stick them on.  I think that if I had had the appropriate font installed, it would have come out with a vaguely Arabic look but it still looks pretty cool to me with a standard blocky font.

I then set out to put a decent coat of finish on it.  I got out whatever I had which was a can of minwax wipe-on poly.  I had previously tested this on a scrap printout to make sure that the poly did not dissolve the printing from the inkjet.  I wiped on the first coat.

Then I was annoyed to find out that the poly seemed to dissolve the spray adhesive and parts of the dial were lifting up.  After the poly dried, I thought perhaps that shellac might work better but things only got worse.  After things dried really well, the paper flattened back out at which point I took a toothpick and put some wood glue under the edges and stacked quarters, coasters, and whatever flat things I could find on the dial to hold it down.  I guess putting a finish over the dial is not in the cards.  From that point on, I just put finish on the wood.  It looks pretty good now.

Another issue is the gear trains.  This is my fault for being cautious.  The drive gear train rotates as a unit and all gears are glued to each other.  When I initially did this I was very sparing with the glue and furthermore, I only applied glue to one surface which is generally a no-no with wood glue – at least in my experience.  So twice now I’ve had the drive gear train come unglued at one of the spacer joints while cranking it.  In each case I disassemble the thing and reglued the joint with an appropriate amount of glue and with glue on both pieces.  Here’s hoping that this will hold although I’ve only repaired two – there are about 10 more similar joints. 

Also, my planet mounts are pretty lame.  As I mentioned before, I drilled these out by hand rather than letting the CNC machine do it and they just don’t fit like they should.  I have to be careful to make sure that none of these planet holders actually touch any of the others or the friction between them will cause the motion to be off. They drag on each other and usually one gets ‘coupled’ to the other.  If I was certain that I’d never have to take the thing apart again, I would squirt some thin CA glue around the shaft and lock them all into place but for now I am considering just remaking these parts and trying again.

So I can safely say that all the parts that were cut by the CNC machine have worked well; my problems have come in wherever I did some hand work.  It’s not that my hand work is sloppy although that is true in one or two places; it’s that I did something without enough forethought and testing.  In retrospect, this is not surprising. Patience is a virtue; one that I am still trying to nurture. If I had gone back to my CAD models and made them match the drawings I had and if I had waited for my friend to get back to town so that we could use the machine, some of these things would have not happened. 

But then again, there’s value in doing something by hand in order to get a full appreciation for what the machine is doing for you.  When I was in graduate school, the machinist who made our experimental apparatus would occasionally make me do some grunt work “to get my mind right” which is kind of the same thing.  So the effort isn’t wasted.  But my orrery still needs to be fixed.

This whole build is starting to remind me of having a newborn child.  The “design and build” process was super fun but now the daily maintenance has begun and that’s kind of a chore.  I hope I can get the thing running reliably and go into a crank-only mode soon.