I need to remove some old split rail fence posts sunk a couple feet in dirt.
I can usually manage to wiggle them a bit loose the use a 2x4 through the hole to make a lever and lift them out. However, I have broken a few 2x4s doing this becuae they aren’t strong enough.
What else could I use for leverage that won’t bend or break that I could buy from a hardware store? Lead pipe?
Lead pipe, including being hard to come by these days, isn’t very strong. You need steel. “Black iron” pipe is commonly available at hardware stores in useful lengths (5-6 feet). Don’t recall what nominal pipe size is 1.5" in diameter, but you can grab a tape measure from the tool department and use it to select the pipe diameter that suits you. If the hardware store doesn’t have the size you need, then bigger building supply stores should have it (e.g. Home Depot).
a steel pipe that diameter would work.
also running something down the outside of the posts on all sides would help loosen. the backside of a shovel towards the post would work. a long bladed tree shovel best.
You can try a San Angelo Bar. It’s a 1 inch solid steel bar about 6 feet long, you can see them on Amazon or Home Depot. Get a steel pipe that fits over the end, and you can increase your leverage.
You need a post jack.
The San Angelo bar would work, and are handy to have around. Then again, a hi lift jackwould also work and are handy to have around.
the bar could work and also be used to loosen the soil around the post. building up a high fulcrum you could then use it as a lever to loosen the post enough to lift it out by hand.
This makes me curious- if you needed the absolute maximum cross-sectional strength you could get, is there anything available in bulk that’s stronger than steel? Something exotic like iridium alloy maybe?
More exotic usually means more expensive.
There are a lot of different alloys named “steel”. Take a look at the Wikipedia article on steel grades.
What kind of strength? Tensile, compressive, flexural, shear, etc.? The OP is wondering about flexural strength, which is sort of a combination of tensile and compressive strength. Materials with high tensile strength, like various polymers, don’t necessarily have good compressive strength. Steel is good on both counts, but I’ll throw out tungsten carbide as a bulk material with the highest overall strength.
Of course things are different if you’re concerned with strength per unit weight. In that case, a composite material is likely your best bet.