Here are some photos of my shop crane. This crane works well and can reach most places in the room.
The main support is 2-1/2" drill stem pipe. If I were going to do this again I would use a larger diameter pipe.
It lifts 300 - 400 lb. easily. The boom is about 15' long and the counter-weight boom is 3' long. I have a 300 lb. weight suspended from the counter-weight boom. Please read the DISCLAIMER