Instructables
Picture of Wizard of Oz Hourglass (Stage Prop)
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I made it at TechShop http://www.techshop.ws

This project was made at TechShop - Detroit for a school play. They needed the Wicked Witch's hourglass. After designing the top and bottom pieces (same piece used twice) in CAD (Autodesk Inventor is available to all TechShop members for free), it was easy to fabricate using the ShopBot CNC Router at TechShop.

Our version is not as ornate as the original movie version, but it actually works, and was very inexpensive.

Materials:

   3/4" particle board
   (3) Ballisters
   (2) 2-liter soda bottles with caps
   (1) 1" PVC coupling
   (6) 1" Drywall screws
   Playground sand

Tools:

   ShopBot CNC Router
   Miter Saw
   Sander
   Drill with various bits
   Countersink bit
   Utility knife
   Scissors
   Hot glue gun
   Masking tape
  
 
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Step 1: Cutting top and bottom pieces

Picture of Cutting top and bottom pieces
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Start off by cutting a top and bottom piece out of 3/4" particle board using the ShopBot. You will want to verify the sizes of your ballisters and 2-liter bottles and create your own cutter paths, or you can download ours at http://www.lime3D.net/instructables/hourglass.zip

Cut the bottle profile 1/4" deep with a 1/8" end mill or Rotozip bit. The pockets for the ballisters can also be cut 1/4" deep.

For the edge detail we used an Ogee router bit. Because it was the type that has the bearing on the bottom (which we removed), it doesn't cut the bottom of the shape, so we programmed the ShopBot to cut the outer profile the full depth of the workpiece (3/4") first, then followed up with the ogee.

Pay no attention to the other shapes in the photos, as we were cutting three different projects simultaneously.

Step 2: Secondary operations on top and bottom pieces

Picture of Secondary operations on top and bottom pieces
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Sand off any rough edges and tabs left behind by the ShopBot. The belt sander at TechShop makes short work of it.

The side that the ShopBot cut is the side that faces inward towards the glass (both top and bottom), so on the back side, use a countersink bit for the drywall screws.
poofrabbit2 years ago
Oh I'm so very excited! One of the plays we are doing this summer at the camp I work for is The Wizard of Oz!!! I am very hands on with the play and make a lot of props and costumes, this will come in so so handy! I will make sure to take a picture of my final product using your amazing instructable!
lime3D (author)  poofrabbit2 years ago
Thanks. Break a leg.