An orrery that you control! I've wanted to build one for ages and finally decided to make one that doesn't rely on finicky gears.

With this one, if you would like to position the planets accurately for any day you desire, you can refer to this:

https://www.theplanetstoday.com

I'm including a CAD model in STEP format, to make it possible for changes to be made to the design. Instructables enables you to view this file in 3D!

Supplies

This projected is designed in imperial units. I would have used metric but for the fact that the copper pipe is central to the design and it is United States 1/4" size.

Sourced from amazon.com:

[1] 9cm diameter wood ball (this is the only metric part). I would have used a slightly larger 4" ball but I could not find one that was 1 solid piece.

Sourced from etsy.com:

[2] 3/4" balls

[2] 1" balls

[2] 1 1/4" balls

[1] 1 3/4" ball

[1] 1 1/2" split ball (buy a few extra)

Sourced from mcmaster.com:

[1] 88755K55 tool steel rod, 2' length

[1] 93744A180 copper washer

[8] 5520K79 copper tee connector

[8] 5520K89 copper socket connector

[8] 5520K601 copper elbow connector

[2] 5520K57 copper cap

[1] 5520K145 copper reducer

[4] 50475K21 copper tubing, 2' length (order 1 extra to be safe)

Copper Lock no heat solder (or regular solder if you prefer)

Laser or CNC cut plywood parts for base, these are 9mm (.354") birch plywood sourced from sendcutsend.com

#4 box nails

A small pipe cutter.

Orrery.step
Download View in 3D

Step 1: Produce Parts for Base

The base can be made many different ways. I chose laser cutting, having the parts cut by an online vendor.

Actually this vendor used a CNC mill to cut the parts but that was fine with me. I used sendcutsend.com and I can recommend them.

These are designed for 9mm (.354") thick material. If you use a different material, the width of the assembly slots will need to be adjusted.

NOTE:

The slots as designed are intentionally a very tight fit. They will need to be opened up a bit with a file. They should fit tight enough that no glue will be required.

Glue a small piece of wood onto the underside to act as a stop for the steel rod.

Step 2: Drill Holes in Wooden Planet Balls

The balls for the planets get a small hole drilled [partially] through. The hole needs to be a tight fit for a #4 nail.

Use a drill press if possible, centering the drill bit as accurately as possible.

Drilling the hole for Saturn is more of a challenge. You want to drill it at an approximate 45 degree angle so the rings of Saturn are tilted.

Saturn needs something for rings. I used a thin sheet of copper cut out with a hole saw. Cut a ring out of the material of your choice. Glue the 2 Saturn halves and the ring together.

Step 3: Drill Hole Through the Sun Ball

No photo for this. A 5/16" hole needs to be drilled through the sun.

My drill press did not have enough travel to drill all the way through this ball. I drilled as far through as it would go, and then used a hand drill with a long enough drill to go the rest of the way.

Step 4: Cut and Assemble Planet Holders

Cut 16 lengths of copper tubing per the attached.

One of the straight connectors needs to be shortened for Jupiter.

Press fit all of the parts together. They will be soldered together after the lengths are checked with a practice assembly.

Step 5: Cut Bearing Parts From Pipe

The 10 bright green parts on the left are short pieces of the copper pipe.

You will need 8 pieces a little less than 1/2" long and 2 a little less than 1/4" long. Cut several extra of each.

These pieces need to have the hole opened up with a 5/16" drill. This is to allow the pieces to slide freely on the steel rod. This will take some practice.

Step 6: Do a Dry Run Assembly

Assemble the parts as shown. This is mainly to ensure all of the pipes are the correct length.

As you can see in the picture on the left, Venus is a little too close to earth.

After you are satisfied with it, disassemble for the next step.

Step 7: Solder the Planet Arms Together

There are at least 2 ways to do this. With traditional solder as used for copper plumbing, or the Copper Lock solder. Traditional solder would look very nice but I wasn't confident enough with my skills. So I tried the liquid stuff and it worked great. I was surprised.

Step 8: Attach the Planets

I wanted to attached the planets so I could remove them if desired. The first method I tried did not work. I squirted some caulking in the hole. The caulking wouldn't dry. So I cut the heads off of the nails. Then I wrapped [a lot] of teflon tape on the nail to make a snug fit when screwed in. Use thick teflon tape if you have it.

Step 9: Final Assembly

Everything should go right together if the previous steps are followed.

I forgot to add that certainly you will want to finish the sun and planets in some fashion. I used thinned acrylic artists colors for the planets and an oil finish on the sun, and the base.

I ended up painting the planets a solid color, but the reason I wanted them to be removable is so I can paint them more realistically if I get inspired.