Checkerboard Method of Enlarging Patterns



The design for any project may be enlarged to any desired proportion by placing a piece of tracing paper which has been ruled with 1/2-inch squares over the pattern and tracing the outline. A second piece of tracing paper is then prepared with larger squares to give the desired increase in size.

For example, 1-inch squares will double the size of the pattern - 3/4-inch squares will increase the size of the pattern by one third, and so on. The outline of the pattern is then transferred to the second sheet by copying the traced outline, one square at a time.

Preparation of Materials

If the children are expected to trace the patterns themselves, care should be taken that the tracing paper is held securely to the pattern and to the piece of wood to which the pattern is being transferred. This may be accomplished by pushing the edge of the tracing paper firmly into the binding of the book or using clips or cellophane tape to hold the tracing in place.

If a soft-lead pencil is used to prepare the tracing, the pattern may be transferred by simply turning the paper over and rubbing the back of the page with a blunt stylus or pencil point wherever the lines appear.

Shop Techniques

Checkerboard Method for Enlarging A Pattern

Lay tracing paper over the design or pattern you wish to enlarge and outline it carefully.

Draw a perfect square around the traced pattern and, with the aid of a ruler, divide this box into any convenient number of small squares.

Decide what size the pattern should be and draw a second square box of this dimension. Divide the large box into exactly the same number of squares used in marking off the original tracing.

Now you are ready to copy the pattern in the large box, sketching one square at a time until the drawing is complete.

This same technique may be used to reduce the size of a pattern, if the box in which the pattern is copied is made smaller than the original design.

Use of Coping Saw and Jigsaw

The difficulty which children encounter in using a coping saw efficiently is largely due to inadequate support for the piece of wood to be cut. The wood must be clamped or held in a vise so that the point at which the saw is cutting is as close as possible to the jaws of the vise or the grip of the "C" clamp.

If this principle is not observed, the resulting vibration or chattering of the board is likely to cause the wood to split. It may be necessary to change the position of the piece of wood several times during the cutting operation to maintain the proper relationship to the vise' or clamp.

When cutting with a coping saw, best results are achieved by using short, even strokes directed at right angles to the wood. The blade should be guided by slowly turning the frame, avoiding any sudden twisting of the handle which may result in broken blades. Detailed figures with sharp angles should be cut from the wood block in rough outline form before attempting to reach the more difficult corners. Very acute angles can best be cut by approaching the apex from two sides instead of attempting to turn the corner.

Teaching these techniques first will greatly help the children master their projects.