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Home built gantry cranes

A degree or two off of slope is usually fine. If it feels a little sketchy you might want to reevaluate what you are doing. The trolley is nice to have especially if you are positioning something. If you are just doing a straight lift off of a vehicle, use a sling on the horizontal beam. Make sure the sling is rated and protected from sharp edges.
 
the thing is...with trolley installed, it is there to use when the gantry is level...if it isnt level, just move trolley to the side & double wrap the cross bar with chain as a non-sliding lifting point...trolley will still be there for next time.
 
Canadium said:
I'm wondering if a trolley is really desirable. If the crane was slightly off level wouldn't gravity pull a loaded trolley crashing to one side?
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That's why I didn't use an I beam for the main. The trolley I designed has a built in brake in it to prevent it moving due to gravity. It will press against the sides of the tube to create friction.

Hacker said:
I would think that if would not be a very good practice to do any lifting with any equipment that is not level.
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My garage door/lane-way is anything but straight or level. the main beam was about a 10 degree incline when I lifted my surface grinder with it. Extra strength and extra rigidity help. It has a lot of slop in the design, which helps it accommodate twist. If you were using a gantry crane only on flat concrete surfaces, it could be a lot lighter build and still be safe.

Hacker said:
You really shouldn't use a gantry to move around heavy loads on an uneven surface.
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absolutely. I have moved loads with a gantry under special circumstances. 1) the load is almost touching the floor 2) I have a very wide stance in the crane, over 6 feet, 3) I move one side of the gantry at a time, moving very slowly, say 5 or 6 inches at a time. 4) the load is stabilized by a second person
 
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I just figure you know what looks safe or not and as far as moving the machine could be anchored at 4 points to the gantry or just one to stop it rolling on the track due to incline. A lot would depend on what you have for wheels that would be my main concern if moving is involved given the types of surfaces used.
 
Here's another home built gantry crane that is designed for heavier loads. One of my friends on another forum built it to move this lathe... I think it is around 12,000 lbs:

IMG_3326.JPG
 
So begins the descent into design, more materials acquisition, fabrication, and... madness. o_O
 
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Clever how the legs/feet lift up out of the way so the wheels work. I suppose that is more to move the crane around and probably not with a load supported? That lathe up in the air is pretty impressive. What weight would that crane lift John?
 
Janger said:
What weight would that crane lift John?
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With the 4 height extenders, it is probably at it's weight limit. on the casters, a little less, because the casters are the weak spot, probably around 8000 lbs, evenly loaded. Take the casters off, and it would easily lift 20,000lbs or 10 tons. (9 tonnes)
 
In that picture , are all three chainfall hoists in use? Tough to see what each is doing


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kevin.decelles said:
In that picture , are all three chainfall hoists in use? Tough to see what each is doing


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The middle one looks like it's attached to a sling going through the casting. it's not quite hanging straight though? The right one though does look like it's perhaps involved too. I see a single chain is holding it all up wrapped around the i-beam? Makes me uncomfortable as big loads always do. That's probably a good thing.

hmm mcmaster has chain 1/2" thick rated for 12000 pounds. pricey.

1618171827689.webp
 
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I talked with him and he thought it was 9000 lbs, but has now reconsidered it to be a little over 8000 lbs. the two small chain falls that are holding the weight are both 2 ton hoists.
 
Here is something for you guys about lifting things - stuff you don't see everyday

Dry Dock 2016: lifting out the Props and shafts from the ship. Weight of each prop and shaft set : 20000 lb (10 tons)

Some serious chainfalls at work - most of they are ones for this application are air driven and in the 15 to 25 ton range. Yard workers weld on the lifting eyes to the hull in order to extract the shafts. Typically just burned out of 1" plate, although now they need a rating stamped on them - did not used to be that way - LOL

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This was the first yard to use a flat bed type arrangement to move the shafts - typically a mobile crane scoots them across the yard. See that saw tooth pattern on the one blade?: we sucked in a piece of mooring line some twit on another ship threw over the side - we sucked it in breaking out a harbour and caught a shackle up in the Kort nozzle. Had to have divers in to lance it out.

I always thought this job would be easier if they had a double gantry and just popped out the shafts easy peasy. I guess 10 tons can be a bit awkward. - Pretty beefy saw horses eh!?
 
YYCHM said:
I agree... I had to look up Kort nozzle:rolleyes:
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Me too Craig, I assume they work somewhat along the lines of an modern day commercial fan jet engine although they pull and push water.
Most likely preventing much disturbance from around the rudder. Just guessing in any case a real monster of a job although when you have the knowhow and right equipment its a cake walk.
 
Sorry @YYCHM and @Dusty - guess I should clarify some of the nautical jargon - LOL the Kort nozzle surrounds the prop and is indeed an airfoil design . Basic principle of operation is to focus the thrust from the prop and channel the thrust that flys off the prop in the radial directions. Increases the efficiency about 10 to 15% over an un-nozzled prop. Used mostly on tugs - adds protection as well. Larger ships without the nozzle can use the radial thrust or side prop wash to “walk” the stern of the vessel. Some times the nozzle is fitted and can be rotated to direct thrust. Some large ships have them fitted for this reason.

I digress....now back to your regular scheduled gantry channel......
 
Brent H said:
Sorry @YYCHM and @Dusty - guess I should clarify some of the nautical jargon - LOL the Kort nozzle surrounds the prop and is indeed an airfoil design . Basic principle of operation is to focus the thrust from the prop and channel the thrust that flys off the prop in the radial directions. Increases the efficiency about 10 to 15% over an un-nozzled prop. Used mostly on tugs - adds protection as well. Larger ships without the nozzle can use the radial thrust or side prop wash to “walk” the stern of the vessel. Some times the nozzle is fitted and can be rotated to direct thrust. Some large ships have them fitted for this reason.

I digress....now back to your regular scheduled gantry channel......
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Please elaborate more. Was the prop replaced or repaired? What were the symptoms that the prop had ingested something?
 
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