How to make a cable dolly

Ever wondered how they get those amazingly steady shots flying through the forest, over a waterfall or between buildings? They do it as a dolly move, and most of the time it is with a cable dolly. The above video shows some shots that were taken using a simple contraption we built in the rainforests of Panama. We're not proposing we have the best design, far from it. Instead we want to show how simple it might be to build a cable dolly to get some pretty professional looking shots.

Step One: Scout the Location

If you're going to build a cable dolly you should have a good idea what you're going to use it for. Depending on the complexity of your shot, you might need something more (or less) elaborate. Here are some scenarios to think about:

• How heavy is the camera?
• Is my camera operator going to be on the cable?
• How far will the cable reach?
  Is it ok to have some sag in the cable?
• What direction will the camera point (strait ahead, sideways, up)?
• What objects are there to attach my cables to in the environment (trees, posts, etc).?

We'll refrain from suggesting all the alternatives for each answer. Use common sense and start simple at first.

Step Two: Materials

Again, there are many ways to build a cable dolly. The list we provide here is for the cable dolly that Ed and Hazen built in Panama.
Pulleys: 2 Bicycle wheels without the tires and tubes.
Cable: 150 feet of static climbing rope or cable equivalent
Frame: Mesh metal piping to construct the cable dolly frame.
Cable Tighteners: 6 carabiners to tighten the rope

Step Three: The Cable

Before you put the dolly on, you must tighten the cable or rope as much as possible. There are many ways to do this, but we came up with a type of pulley system to leverage our rope. See how we used the carabiners in the photo to act as pulleys.

Make sure your cable is in a slight downward angle. The angle only has to be enough to get the camera moving. A 5% grade should work well, but since it is unlikely you'll have a way of measuring the grade in the field, use common judgment and experiment.

Step Four: The Dolly

The last step is attaching the actual dolly mechanism to the cable or rope. Because our unit is fixed we had to take off the wheels and reassemble it.

There are two options now. You can either walk with the dolly as it moves through the forest or you can let it run free.

We prefer letting it run free as the shots are always smoother.
However, if you do walk with it you can angle the camera as you walk to make sure your subject stays in frame.

Experiment as much as you can. We're sure that what you come up with will likely be much better than ours. In fact, leave a comment and let us know what suggestions you have to make this even better.