Introduction: Bolt Closure Envelope

I made a Fathers' Day Card that looked like diamond plate, and I wanted an envelope to match that wasn't just a repeat of the pattern. One day, while fiddling with a bottle cap, it just hit me: a bolt!

Step 1: Required Items


  1. plastic bottle with screw-type cap (the really flat caps are best)
  2. envelope
  3. card stock
  4. self-adhesive foam mounting square


  1. box knife
  2. diagonal wire cutters
  3. scissors
  4. glue
  5. pencil
  6. ruler
  7. protractor - I you don't have one on hand, you can do what I did and just print one from here.
  8. tooth pick
  9. craft knife

Step 2: Separate the Bottle Parts

You can use pretty much any bottle with a screw-type cap. I recommend emptying and rinsing it out before cutting into it to avoid stickiness.

Use the box knife to cut just under the flange that is below that weird pokey-ring that seals the lid.

Use the wire cutters to snip off the pokey-ring.

All you need here is the cap and the threaded section of the bottle down to, and including, the flange.

As for the rest of the bottle, this looks like a nifty idea.

Step 3: Prep the Envelope

Pretty much any kind of envelope will work for this. For this Instructable, I used the envelope from a half-fold greeting card.

Measure the width of the flap on the envelope. Mark the horizontal center of the envelope on the very bottom edge of the flap and just below the flap on the envelope body.

Using the inside of the threaded section of the bottle, draw a circle on the envelope flap, then lift the flap and draw it underneath, as well. This should leave you with a half-circle on the flap and a full-circle under it that lines up perfectly with the half-circle.

Step 4: Cut the Full-Circle

Fold up a scrap piece of card stock or use a small cutting mat, and slip it behind the full-circle on the envelope. Using your craft knife, cut the circle out completely.

The circle-hole should be just barely too small for the threaded bottle piece. Cut the paper just enough so that you can get the threaded piece to screw into the hole. It should be very snug so that even without the cap, it won't fall out. The extra I had to cut was about a millimeter thick.

Step 5: Cut the Half-Circle

Place the cap on the flap over the half-circle, centering it over the first mark, and trace it to make a double half-circle.

Split the difference between the two half-circles, and draw one more. The center half-circle is where you cut.

Your envelope can now be kept closed with the cap.

Step 6: Reenforement

Without the cap on the threaded piece, use a toothpick, spread a tiny bead of glue around the threaded bottle piece between the flange and the envelope. Press the flange to the paper firmly for a few seconds.

This will probably not hold very securely on its own, so cut a piece of card stock that will cover the flange, and spread glue on it.

Paste the card stock inside the envelope, covering the flange.

Allow this to dry completely before trying to screw the cap back on it.

Step 7: Create the First Hexagon

Place the cap on a piece of card stock, and trace it.

Draw a straight line through the center of the circle, extending it well beyond the circle.

Use a protractor to draw lines at 60 degrees and 120 degrees. Extend those lines out in both directions.

Remove the protractor, and complete the lines to leave you with six equally spaced lines radiating out from the center of the circle.

Using a ruler, find the distance from the center of the circle to the edge of the circle (radius). Add one millimeter and mark each line at that length from the center of the circle. Do this all the way around.

Connect the marks on the lines around the circle to make a hexagon.

Step 8: Create the Second Hexagon

Measure the height of the bottle cap.

Add two millimeters to that number.

Draw lines that far from the first hexagon to create the second.

Step 9: Mark the Flaps

Line a straight-edge up with the ends of two of the parallel sides of the small hexagon.

Draw lines along that straight-edge outward to the edges of the larger hexagon.

Step 10: Create Glue Tabs

At the corners of the hexagon are little kite-shaped sections. Using scissors, snip each of these across the widest part to leave just the longer triangles behind.

Cut the line between the tiny triangle and the rectangle next to it. Do this to every triangle, but only on one side of each so that you are left with six crayon shaped sections around the smaller hexagon. (See the shaded part in the photo.)

Fold each little triangle where it connects to the rectangle.

Step 11: Make the Folds

In order to not have the lines all over the finished project, trace the lined part onto another piece of card stock and cut it out.

Fold all of the little triangles as before. Also fold all of the flaps in the same direction.

Step 12: Glue!

Using a toothpick, spread a tiny amount of glue on the outside of the triangle and press it to the inside of the corresponding rectangle.

Hold for a few seconds, then continue doing the same on every triangle.

Step 13: Mount the Cap

There are a lot of types of double-sided sticky foam square things. I used the kind that is for hanging things on walls temporarily. Just cut a little square that will fit in the hexagon.

Stick the square in the hexagon, remove the sticky protector, and push the cap in, threads exposed.

Step 14: Finish

Allow everything to dry completely, then just screw the "bolt" in place.

Reuse Contest

Participated in the
Reuse Contest

Unusual Uses Challenge

Participated in the
Unusual Uses Challenge