ZEONHAK 14 PCS Wedge and Feather Shims, Heavy Duty 5/8 Inch Plug Shim and Wedge for Stone, Rock, Granite, Marble, Concrete

I bought these with hopes of breaking up a 1000 pound concrete post support. I used these with the recommended 5/8" holes and they just sunk into the concrete without breaking it. I tried 3/8" hole with the same results. I'm sure they would work to break rock. I did buy an electric 35 pound jack hammer on Amazon, that did take the concrete apart. No hard feelings live and learn.

I'm busting up Colorado granite in my future parking area. These wedges along wirh a DeWalt bit in a Bosch Bulldog are still going strong after 5 3' or larger rock splittings. Maybe 70+ holes. I put all 14 into the top of this rock, expecting it to break vertically, instead it split the top slab and also left a nice flat, below grade, surface. The bar shown is 5' long and this rock is over 4` tall. The 14 wedge sets are 3 pieces each with a heavy elastic band holding them together, a basic but exceptionally practical design. With my 3 lb. mallet, the force exerted by these wedges has to be greater than 10,000 psi, each. It may be manual and "old school" but it wurks. Listening to the granite crack is strangely satisfying and you can feel the rock and wedges start "singing" right before it splits!

If the little rubber band that holds them together breaks as you're using them don't worry about it you really don't need them.

Worked great breaking up a 1600 lb slab of concrete.

I have used these for a few months they hold up well rebuilding stone wall that fell down on my property recived them in a timely manner .

We have a hard sandstone in our area that won’t even break down with a sledge hammer, but they are no match for these wedges. Now, our rocks can be turned into something useful.

First time using these, breaking a large rock a little at a time. Working very well, and they aren’t letting me down.

Split as designed. Worried I’ll brake the rubber ring but it is working for now