2007Arms forum
Adding extra lift to a Steadicam arm using rubber bands
19 years old. Gear and prices may have changed since.
What the thread found
- Stretching heavy-duty rubber bands diagonally across both sides of each arm section can provide additional lift of approximately 5-6 pounds.
- The rubber bands are attached by screwing short quarter-inch 4-40 bolts into the internal threads of the arm's trunnions.
- Adding rubber bands reduces the arm's linearity and iso-elastic behavior, making it less smooth and more resistant to lifting or pushing, but this effect becomes negligible when counterbalanced by the inertia of heavier camera payloads.
- The method is inexpensive, costing around two dollars in materials.
- Not all arm models may have sufficient trunnion threads available to safely secure the bolts.
- Medical tubing has been used as an alternative to rubber bands for the same purpose.
Depends on
- The arm's spring rate changes more dramatically with position than normal operation.
- Bolts can work loose from their threads during handling between shots if the trunnion has limited threading.
- The technique was tested only with heavy IMAX cameras and may not perform the same way with lighter camera packages.
- Improvement in lift appears proportional to the number and strength of bands used, but exact calculations were not worked out.
- Some arm variants have more usable threads than others, affecting the reliability of bolt attachment.