Some may wonder why I was asking about the tonnage. It's very important for what I use the hoist for. It's not for engines since my 2 ton can pick up a truck diesel engine no problem at all.
I have a rather long story of how I use engine hoist for loading and unloading machines. My first time using it was for my Leblond lathe. It was hard. Even though removing both bottom cabinets, it was still supper heavy and unwieldy to deal with. For example, once lift it up, I need to line it to the back of a truck, which means the two legs of the hoist and then the top hitting the beams.
I managed to get it on, but it was one of the hardest day I remember. Taking it off was surprisingly easy since I do it at home. Somehow, at home, I was always having an easy time loading/unloading big items. I can always find a piece here, a stick there, just something that works for me that I can't when not home.
The second big move was my horizontal mill. I researched on the weight, welded up a bracket for anchoring it. It lifted up the mill, but couldn't lift high enough and safely onto the truck bed. It was rather scary. One of the two legs of the hoist started to lift up a tiny bit. That was it, but I got luck and someone with a forklift helped me. It took 30 seconds for them to do it I think.
Once I got it home, I made a "tall" hoist by taking a U shape 2x3 metal tube from an exercise machine, turn it upside down. I think it's about 6 feet tall. I then have two long legs, probably 2x4 metal tubing each on each side. On the back, I had 2 turnbuckles and 2 long 1/8" metal strips for pulling it back. On top, I put the the engine hoist without legs on it. That did the trick and it was tall enough to pick up the mill from a truck bed.
The 3rd big move was to get a vertical mill, about 2100 lbs. Using the same "crane" above, it didn't work. The legs bent a bit, and the point where I bolted the hoist to the upside down U metal tubing gave out and bent. Out of extreme luck, a gentleman helped me with a fork lift. I thought at home that if it couldn't do it, I could remove the motor and the head and even the bed to reduce weight. But away from home, anything as simple as that became a big problem. Time seems to fly by very quickly tool. Just a blink and several hours went right through. It would be a big problem because the crane was badly damage that I may not even able to use it for removing the bed or the head/motor. They are much heavier than I thought when I removed them at home. The motor was also very hard to remove because of stuck belt and odd way to remove a compressed spring (variable speed).
So when I got home, my mission was to build a crane. It took some thinking and some design. The constrains were what I got laying around, minimum purchasing, must work, and reusable in the future (not a one shot use).
Below is what I designed. In the 1st try, there was no "bottom" diagonal supports. That didn't work. I test lifted a 270 gallon water container and the legs started to bend. So I added the bottom diagonal supports for the two legs (I only draw partially below, and the dimension is not exact).
There are also 3 cables not drawn from top going down. One cable goes from the rear to the bottom of the vertical beam. Two cables, one each side, goes from top of vertical beams (you can a little dot there) down to rear most of the legs. One more constraint I forgot to mention was to easily remove apart and carried around. The arm also needs to extend far enough into the truck bed to pick up stuff easily.
At the end, it worked. The crane is 13 feet tall at the top beam (it's taller if use total height).
The top beam/arm can extend out. So the tensioner on the front must be adjustable to that length.
The 13 feet vertical beam has 2 segments. One is approximately 7 feet and another 6 feet. So I can remove the top, use the bottom only. But it doesn't work with the shorter version yet because 3 tensioner cables needs to be split in two to accommodate for different heights.
It's very heavy to set it vertically with 2 people. I hope that with 6 feet section removed, it would be much easier. I think 13 feet is just way too tall. I added extra height for chain hoist hookup.
