Introduction: Arrow Through Coke Bottle - Four Variations

By tomatoskins
About: My name is Troy. I'm a Mechatronics and Aerospace Engineer. I make things out of wood and electronics and spend time outdoors (especially SCUBA diving).

Out of the many impossible objects, there isn't any as infamous as the Arrow Through Coke Bottle. This puzzle features a solid wood arrow with no glue or joints through a solid glass coke bottle. I remember as a child looking through various puzzle books and having this one stand out above all others. The puzzle was designed and made a reality by Gary Foshee in 1979. The mechanics behind the puzzle were known long before and published in a book by Albert Hopkins in 1897 titled, "Magic".

This instructable outlines the classic Arrow Through Coke Bottle along with three other variations in the last three steps. If you love impossible objects, you will love the solution to this classic Arrow Through Coke Bottle.

Step 1: Tools and Materials

Tools:

Materials:

Step 2: Wood Selection

The selection of wood is extremely important for the arrow. I used an old dry pine board reclaimed from a bunkbed. You want grain that runs perpendicular to the face of the arrow. This will ensure that when the wood is clamped in a future step, it can compress evenly and square. If the wood is at an angle it will not compress as small as possible and will result in being skewed.

The second image shows the difference between an arrow with straight grain and slanted grain once clamped.

Step 3: Cut Arrow

Using the PDF template uploaded to this step, cut out the arrow from a 1/2 inch piece of pine. Avoid knots!

↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓ Download Template Here ↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓

Attachments

Step 4: Sand Arrow

Using a disk or hand sander, remove the excess wood and round the corners. Remove the template.

Step 5: Boil Wood

Once you have a few arrows made, boil the tip for 45 minutes. This will make the wood extremely pliable and able to be compressed in the next step.

Step 6: Clamp

Using a strong clamp or vise, compress the wood until it is as small or slightly smaller than the middle shaft of the arrow. Use only one arrow per clamp so maximum force can be applied. If you notice that small cracks are appearing, that is alright. Small cracks will disappear later (large cracks shown in the last image will not disappear).

Set the arrows aside and let them dry for 72 hours (48 hours minimum depending on your local humidity). If you notice that the arrow is starting to expand again when opening the vise, clamp it down again and wait another 24 hours.

Step 7: Remove Unwanted Printing

While the arrows are drying, get the bottle ready. Every Coke bottle comes with unwanted printing that will distract from the completed puzzle such as expiration dates and nutrition facts. Using acetone and paper towel, rub off this unwanted printing to leave a clean non distracting bottle.

Step 8: Prepare to Drill

If you are planning on only making one puzzle or you do not own a drill press there is no need to make a holder for the bottle. There is a great instructable by Shake the Future that shows how to drill glass if you don't have a drill press.

I made this holder using an old bucket and some scrap pine for the supports.

Step 9: Drill the Bottle

Mark the location of your holes. Try to stay away from the logo as it can chip. Keeping the glass below water, drill with a 9/16 inch or 14 millimeter diamond drill bit. Use light pressure with your drill running about 1000 RPM to cut the hole. When one hole is complete, rotate the bottle and drill the second hole.

Step 10: Finish the Hole

Using flat diamond files, submerge the bottle underwater and finish the hole. Use the completely dry arrow to verify the size (try to keep the arrow as dry as possible). Start with the coarse file from the set and once it is the right size that the arrow can pass through it, polish it up with finer files.

Step 11: Insert Arrow

Once the holes are the correct size, insert the arrow through each hole.

Step 12: Boil the Arrow

Boil the tip of the arrow. This will rehydrate the arrow and allow it to expand to it's original size. This step can take up to 10 minutes. Once the arrow is back to it's original size, remove it from the water and allow it to dry for 24 hours.

Step 13: Hand Sanding

After drying, the arrow will not be smooth as it once was. Use increasingly finer sandpaper until the wooden arrow is smooth.

Step 14: Variation One - Arrow Through a Bottle Through an Arrow in a Bottle

The following variations use the same general methods as the original:

  • Cut a 5/8 x 5/8 inch hole in the tip of one arrow
  • Boil and clamp the two arrows
  • Once dry, insert the arrow in the neck of the bottle
  • Fill the bottle with water to cover the head of the arrow and set in boiling water
  • Drill two holes in the site of the bottle
  • File the holes square to fit the second arrow
  • Insert the second arrow through the bottle and the first arrow
  • Boil the tip of the second arrow

Step 15: Variation Two - Two Arrows Through a Bottle

  • Boil and clamp two arrows
  • While the arrows are drying, drill two askew holes in the bottle
  • File the holes square once the arrows are dry.
  • Insert the arrows through the bottle and boil

Step 16: Variation Three - Arrow in a Bottle

  • Boil and clamp arrow
  • Once dry, insert the arrow into the neck of the bottle
  • Fill the bottle just above the head of the arrow and place in boiling water