mr. science - make a pantograph

How to make a pantograph

What is a pantograph? This is a handy instrument for copying line drawings or other pictures, and enlarging or reducing them in the process. Here we'll make one that enlarges the original by 2.

What you need:

  • Corrugated cardboard: I used a pizza box. (Medium, from Carmen's - the best!)
  • 4 pushpins, the kind you use on a bulletin board
  • a pencil with a sharp point
  • a 1" drywall screw, or something similar. A straightpin will work too.
  • a scrap of wood, about 3/4" thick.
  • a nail (or a straightpin, if you can get it into the wood)
  • masking tape
  • a cork (optional)

a pantograph

Now build your pantograph:

  1. Cut 4 strips out of the cardboard, about 3/4" wide, and 13" long. Cut parallel to the waves in the cardboard, not across them.
  2. Lay them out according to the picture above, and mark with pencil where the various holes will go. Note that the numbers in the drawing are the distances (in inches) measured between the holes, not from the ends of the cardboard strips.
  3. Assuming you have a sharp pencil, you can gently drill it through the cardboard by pushing and twirling.
  4. The pushpins go in upside down. If you want, you can put a piece of cork over the sharp end that sticks out, for protection.
  5. The screw screws through the cardboard in its position.
  6. Tape the piece of wood to the table.
  7. Hammer the nail through the cardboard into the wood, just enough to make it stick.

Now you're ready to use it!

  1. Take the small drawing or picture that you want to enlarge, and put it under where the screw is. The tip of the screw is your pointer. When you pick up the pencil and move it around, the pointer will move across the small picture. Make sure you can cover the whole picture with the pointer. Adjust the height of the screw such that it just touches the surface.
  2. When you're sure you can cover the whole picture , tape it to the table with masking tape.
  3. Take a piece of paper, and put it under where the pencil is. Pick up the pencil and move it around, making sure that as your pointer goes from the left edge of the picture to the right, and from top to bottom, the pencil is still somewhere over the paper. When the paper is in the right place, tape it down too.
  4. Now copy the picture by putting the pencil down on the paper, and draw lines as you keep your eye on the pointer, to make it follow the lines in the original. You get the most accurate results if you hold the pencil, or the cardboard strip near it, very lightly, so as to not to twist the assembly.

Other configurations:

After playing with this one a while, you'll figure out how it works. How would you arrange the pieces if you wanted to enlarge something by 3? What if you want to reduce a figure?

Some special tips for the sunspotters:

Why do we have this thing on the sunspotter page? After you have made a number of consecutive observations of a sunspot, and you have your little stack of 3x5 cards, you should copy them all onto a single 8.5x11 sheet of paper, and enlarge the image in the process:
  • Instead of taping the 3x5 index card to the table, put a double strip of masking tape on the table along 2 sides of the card, so that you can slide the index card up against the strips of tape.
  • Now you copy the first card of a sunspot series, by sliding it into place against the strips of tapes. Then, you get the next card, and copy just the position of the sunspot.
    This way, you get onto one, enlarged image, all the positions of the sunspot that you've been following.

    2 April 2002 - Hubert van Hecke
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