We've recently bought a wooded lot and there are boulders on it that I want to move for landscaping. I have a block and tackle set and wagon rated at over 1,000 lbs each and a cargo netting rated at over 800 lbs. My original idea was to buy 5 pieces of 6' angle iron, use 4 of them for "A" frame legs at the two ends, with the last one going between them (in other words, it'd look like a child's swing set). I'd use chains on the As to keep the legs from spreading (and footing so the legs don't sink in easily). One added advantage is this would be easy to take apart and reassemble, since I'd be using it in areas where I can't get a vehicle.
My issue is whether the 2" angle iron I can get at Lowe's can hold enough weight. I'd like to be able to consider this rated at a 500 lb work load, which would give me a good safety margin. I seriously don't think I'd be lifting anything over 300 lbs, but I can't exactly weigh the boulders before lifting them. (I do know granite is 175 lbs per square foot, as a "heaviest case" example.)
I know if I bolt two pieces of angle iron together for the cross piece that will strengthen it. I don't know if I should bolt them in a U shape or more like a T shape. I also don't know how much "off the shelf" angle iron will hold.
I'm open to using other materials. I even considered using the steel ramps from Northern Tool that are rated above 500 lbs to make the A frames at the end and, perhaps, one of them as the cross piece.
I'm open to suggestions about design changes, material changes, and more. I did consider using a come-along and just dragging boulders, but that's going to scrape up and destroy the cargo net rather quickly and you can't really predict how a boulder will drag of it it could suddenly slide into a new position or start rolling.
I've noticed this is getting a fair amount of views, but no response.
Is there a way I can clarify what I'm planning and asking?
I'm hoping to find out how I can find out if off-the-shelf angle iron will hold a 500 lb working load and, if not, what I should use instead. But I'm also quite open to any comments about if there are suggestions on making this a safe design.
Have you looked through the sites engineering calculators to check your proposed angles?
You haven't gotten any responses because even though your question is a simple one, the answer is not. It depends on so many things other than the size of steel you use: the actual geometry, the location and type of joints and connections, the method of loading, etc.
So, here's my thoughts... Building this lifting device is interesting, however I wonder if you simply borrowed or rented a tractor with a front-end loader and did the lifting that way would be faster and less time consuming...
There are those walk-behind rent-able front end loaders that may make more sense...
If I where to need a lifting crane I would consider 4x4 landscaping timbers as opposed to angle steel. When done with the timbers you can then use for landscaping....
Last edited by Kelly_Bramble; 03-17-2016 at 08:33 AM.
Tell me and I forget. Teach me and I remember. Involve me and I learn.
Without going into details, I can't get any vehicle into this area. For now, I have to carry anything in.
I haven't gone into angles and such because my main concern is the one horizontal cross piece at the top. That one piece is the one that will hold the full load. If I use the same material for the legs as the cross piece, and there are 4 legs, then the weight on the legs will be distributed, won't it? So I would think the main issue is to find a material I can use as a 5 or 6 foot beam across the top that would hold the full 500 lbs without giving in would also work for the legs.
Doesn't that reduce the problem to the main issue of finding a material I can use for a 5-6' crossbeam that will hold 500 lbs?
and the wagon?Originally Posted by Tango
see:I haven't gone into angles and such because my main concern is the one horizontal cross piece at the top. That one piece is the one that will hold the full load. If I use the same material for the legs as the cross piece, and there are 4 legs, then the weight on the legs will be distributed, won't it? So I would think the main issue is to find a material I can use as a 5 or 6 foot beam across the top that would hold the full 500 lbs without giving in would also work for the legs.
Doesn't that reduce the problem to the main issue of finding a material I can use for a 5-6' crossbeam that will hold 500 lbs?
Beam deflection and stress equations and calculators
Specifically:
Beam Deflection and Stress Supported both ends load in middle
I recommend a 4 x 4 post or landscape timber... 500 # down the middle should be no problem..
Also see:
Engineering properties wood
Area moment of Inertia Square
or
Area moment of inertia menu
Last edited by Kelly_Bramble; 10-22-2022 at 08:18 AM.
Tell me and I forget. Teach me and I remember. Involve me and I learn.
A 4x4 would work just fine. I can go with that and deal with it easily. Thanks!
I already have the wagon in there, so it's not an issue. I had to carry it through some muddy parts, but it's there. Eventually we'll have this all more "settled." There are wetlands on the lot, so we have both the practical issues (muddy areas even a 4x4 has trouble with and a creek crossing in soft sand) and legal issues (wetlands regulations at federal, state, and local levels). We have a firm working with us to get all the permits and that's going along. (Just ripping along at the speed of government regulatory red tape.) (The wetlands situation also means I can't cut down trees or saplings for access.)
Also, for the places I need to get to, there's some narrow trails I can manage to keep the wagon on. I wouldn't want to try it with anything wider than what I've already used in there.
If the frame is based on soft/wet ground, you may need to throw some spreaders under the frame legs. If you get any uneven ground penetration it could make the whole thing unstable. Or knock the legs in until they start to reject the blows and cut it all level.
Thanks - yes, I figured if I had angle iron legs, that they'd dig in pretty easily (and one issue about why I can't get many vehicles in is soft ground in some areas), so I figured I'd have to use some kind of footing. I didn't mention that previously because I was more concerned with the issue of the working load.
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