# Wrong calculation DIY crane

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• #48022

I realy like the video tutorial of building your own crane. I’ve build quit some cranes myself and I do an an engineer.

For that I’d Like to ad a warning/correction on the tutorial. The calculation of the counter balance is wrong!!!!!

Brian Peterson calculates:

The given weight is 10 pounds for the camera. If the tripod was in the middle there is indeed 10 pounds needed to balance is….given the fact that the total length of the boom is 20ft. To calculate the momentum on the tripod u have to use the following formula. In balance it’s 10 pounds times 10 (the length of the boom) this is 100….

To calculate the counterweight use 100/10(the length of the other side so thats 10…. this is a situation in balance.

In the video tutorial the given weight of the camera at the end is 10 pounds with a length of the boom on that side of 15. So calculate 15×10 is 150 pounds of momentum…. To counterbalance this weight calculate 150(the momentum /5(the distance on the other side of the tripod, is 30 pounds.

It’s only a difference of 10 pounds in this case, but with bigger cranes and heavier camera’s this wrong calculation can cause serious damage of injury!!!!!!!