Gantry Cranes

rwm, you acted so fast that I missed this entire thread while I was away on holidays, and now you have it...

So even being late to the thread I thought I'd mention a thing or 2... Our HF 'princess auto' had 1 and 2 ton gantry cranes for sale here, but when I looked at them and turned a 'engineer's eye' to them the seemed to be very seriously overrated. I might trust the 2 ton to lift a 750 lb load, but not if there was anything out of level with the location of the crane....

So for the price I made my own, learning a ton (!!) of stuff while doing it. I paid a little more than the price of the 2 ton without a trolley, but have a crane that will easily handle more than I'd ever lift.

I sent my drawings and pictures to a relative who runs a crane building/design firm, and he says that my rated capacity should be about 4 tons (so I overbuilt it a little)....

so my next project is to build a trolley: my main beam is 4" X 8" .188 wall tubing, as no commercial trollies will fit it.

Here it is hoisting my 2000 lb surface grinder :

4Mike-grinder-extended.jpg
 
Last edited:
Dabbler- Very nice crane you have built there. Mine is the 2 ton unit. The main beam looks adequate. The side posts look a little sketchy for 2 tons. I would probably never move more than a Bridgeport and it should be adequate for that. I feel like keeping the casters locked will be key. I still need a way to lock the trolley.
Robert
 
rwm, can you just put a threaded hole in the trolley, with a set screw that bears against the main beam?
 
I still need a way to lock the trolley.
Robert

Definitely don't try and lock the trolley, they are meant to not only allow you to move the hoist/lifted item into position, but to also mantain the overhead lifting point above the center of balance of the object.

For instance, if you wanted to stand a tall item up (a post or something), the trolley would be centered over the lifted end at first, and would then move closer to the low end as you raise it up. This is to prevent a shifting load and reduce sideways forces on the gantry (not fun to see a gantry flip). Also note that the 'safe' way to stand something under a gantry is to have the item lifted parallel to the beam and not perpedicularly.

If for some reason you absolutely need a fixed lifting point (second pick point etc) a short lifting sling choking the beam can serve well enough. You can also bolt on a purchased/fabricated seperate stationary pick point.

No offense intended, but it doesn't seem like you have a lot of experience with rigging. I would recommend finding someone who can teach/help you with any big lifts for a while, or at least purchase some books on safe rigging practices.
 
Definitely don't try and lock the trolley, they are meant to not only allow you to move the hoist/lifted item into position, but to also mantain the overhead lifting point above the center of balance of the object.

For instance, if you wanted to stand a tall item up (a post or something), the trolley would be centered over the lifted end at first, and would then move closer to the low end as you raise it up. This is to prevent a shifting load and reduce sideways forces on the gantry (not fun to see a gantry flip). Also note that the 'safe' way to stand something under a gantry is to have the item lifted parallel to the beam and not perpedicularly.

If for some reason you absolutely need a fixed lifting point (second pick point etc) a short lifting sling choking the beam can serve well enough. You can also bolt on a purchased/fabricated seperate stationary pick point.

No offense intended, but it doesn't seem like you have a lot of experience with rigging. I would recommend finding someone who can teach/help you with any big lifts for a while, or at least purchase some books on safe rigging practices.

I have no experience in rigging! Thank you for the tip on the trolley. That makes perfect sense. I will do some research.
Robert
 
I have no experience in rigging! Thank you for the tip on the trolley. That makes perfect sense. I will do some research.
Robert

Most important 'rule' is fingers and eyes go over every square inch of rigging gear before being used, every time, to check for defects or wear problems.

Other than that it is the same as running machine equipment for the most part, need to have the right gear to do different lifts/moves, and need to know how to use it.

You can do a lot with a few different length strap pairs, some shackles, and a dog chain or two (be sure to never load both sides of a chain if you use these). Other than that it depends a lot on what you need to be moving.
 
rwm, if you don't want to have a movable trolley, wrap a chain around your main beam and hoist from that.

I'd be very wary about drilling any holes in the trolley or altering it ain any way. In my structures class in U. we took transparent stress models and drilled holes in them, and found that the stress concentrations change radically. In most designs, there is a lot of redundancy and overbuilding, so no biggie. These trolleys from offshore have no safety factors or extra strength built in - a hole can be disaster.
 
I would recommend finding someone who can teach/help you with any big lifts for a while, or at least purchase some books on safe rigging practices.

@Timwalker , Can you recommend any good online or book resources for rigging basics?
I have always wanted to learn more.
Thanks,
-brino
 
0714191940.jpg
The cross beam now has a couple bolts on each end going through the upright holding the beam in place. The 2x12's are not laminated. It is MUCH easier to put them on one at a time when setting up in a tight space and take them off one at a time when dissembling. They would be stronger if they were laminated.

0714191939c.jpg
Only the 3 center beams of the upright are laminated together. The two outside supports for holding the beam are just bolted onto the upright.

0714191939b.jpg
The extra 2x4's glued to the uprights at the base are really only there because they were lying around when I was putting it together... but the "official" explanation is they give a bit of extra support to keep the beam from falling over left or right by increasing the distance between the bolts.

0714191939a.jpg
The angled braces fold down to between the 2x4 base for storage. If you look close at where they attach to the base one has the block on top of the base the other one has the block below the brace so they fold on top of each other neatly for storage and transport.

When broken down I can pretty easily move all 5 pieces myself in case I need to move it the the sellers location to load my trailer.
 
Last edited:
For those making a wood gantry i would suggest that you look into "Laminated" beams using Plywood.

In my experience for example i found using two 2x8's glued and screwed onto each side of a 3/4" thick structural plywood gave me more lifting capacity without sagging and being lighter weight compared to using three 2x8's. Do your own research to be sure your building it safely and you will not have a problem so long as you pay attention to even the small details when lifting heavy objects!
 
Back
Top