I've been jealous of JD4044M's boom crane. There are times when you need a lift in a tight place and need to control the lift with precision. I use my FEL bucket with hooks and D-ring clevises to lift a lot, but the bucket really blocks your visibility and it can really be in the way for a tight lift. So I decided to make my own crane for my FEL using the Artillian fork frame as a base. It turns out that its features are well-suited for this project.
The basic crane is shown below. I used a piece of 2" square steel tubing for the boom (the same type of steel used in trailer hitches).
The boom is mounted in the trailer hitch on the fork frame.
The support chains connect into the upper chain slots on the fork frame. They can be made nicely taut without using anything to tension the chain, such as a turnbuckle.
The upper and lower shoulder ring bolts at the end of the boom are mounted with a connecting nut inside the steel tube. The 2" connecting nut has been ground down on one end so that it fits perfectly tight in the end of the tube (had to tap it in). My goal was to keep the forces on the rings from acting to distort the sides of the steel tubing and cleanly transmit forces on the rings to each other.
The maximum lift height of this crane is about 9 1/2 feet. You could use it to move material to a low roof edge, but most of my house is 2 stories and the garage has high ceilings. It won't reach the roof on any part of my house.
For really tight lifts, I also have the hardware for a center chain option for cases where the side chains might be in the way. When moving big loads, the inertial forces to get them moving and stop them can create lateral forces on the boom. The side chains are preferable for providing support to protect the boom in these cases.
I was able to get the center chain taut using standard components. I had to lift the boom with my knee while I used both hands to get the clevis connected. Not easy, but it was possible. (I should sell videos of this stuff.)
A key question in this design is "How much leveraged force can the trailer hitch in the fork frame handle?". It turns out that it should handle over 600 lbs without even considering the effect of the support chains. The H120 loader can only handle about half that weight at the end of a boom as long as this crane. So I'm pretty confident that the hitch in the fork frame won't be damaged. My math is below, and a pdf is attached. Those of you with serious skills in this area, please advise me if I'm off base.
I will supplement this post with future posts on (1) testing the crane, (2) adding a winch, and (3) storing the crane.