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harmonograph free plans: how to make a
Large Harmonograph
Basic Description

watch the
animated intro
A harmonograph is a pendulum-based drawing board that produces beautiful curvaceous drawings. After you give the large hanging platform a gentle push, gravity works its magic while a pen records the results. Each swing is almost identical to its predecessor: the minute discrepancies are responsible for the remarkably sinuous curves. The version that we have detailed in the plan below allows you to make drawings on paper or on an erasable whiteboard. You can set up the harmonograph in a garage or basement and hoist it out of the way when not in use; it ends up taking virtually no space at all. We love to enjoy the mesmerizing action, but it makes a great conservation piece at a party and kids absolutely love it! It takes some patience to get everything working right, but it is definitely worth the fine tuning that this project requires; as always, we will walk you through all of the steps.

step:               6        

Now let's make the ceiling mount to complete the drawing board. Cut a piece of plywood that spans the distance between the joists that you will mount to. We situated our harmonograph in a workshop with an open ceiling. If you have a different mounting situation, then you will have to adjust the design accordingly. A general rule that we have been satisfied with is that the distance between the mounting points on the ceiling should be about 1/5 the distance between the mounting points on the drawing board. Accordingly we made the ceiling mounting points about 10" (25cm) apart.
ceiling mount
You are trying to minimize friction so although an eyebolt will work fine, we found that a hole, slightly larger than the diameter of the string, works better. You simply pass the string through the hole and tie a knot in the end to prevent it from falling through. You may be tempted to loop the string around to use one length of string for two of the lines, but it's best to have them independent because in case one of them is compromised, the other three will be able to support the drawing board.
We marked a grid pattern on the ceiling mount and drilled a few holes, that allowed us to easily alter to positioning of the strings which provides differing drawing results. Ensure, however, that you securely fasten the mounting board to the ceiling joists: we used four heavy screws.
Cut four lengths of string to about 8' (2.4m) each. We have found that the installed string length (as opposed to the overall string length) should be about 1 1/2 times the distance between the mounting points on the drawing board. Since the distance between our mounting points is 4' (1.2m) , we aimed for 6' (1.8m) long strings; note that the excess is for adjustment and to pass though the mounting holes and around the hooks. If your ceiling is higher, give it a try, you will be able to make other adjustments to make beautiful drawings. Choose string that is strong, but avoid thick rope because of the increased resistance to bending; we used 1/8" (3mm) nylon cord, and lightly melted the ends with candlelight to prevent fraying.

◄ step 5   —   step 7►

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