Drilling to break large sandstone and limestone boulders

To split a large lump of sandstone or limestone I would recommend a set of plug and feathers along with a standard sds drill and bits. The size of drill bit will obviously depend on the size of the plug and feathers. Contact a good masonry supplier and they would be able to advise on the size needed.

I would drill holes along a straight line and use steel feathers and pins and hit with hammer evenly until it splits till manageable sizes for what you requiire

Hammer and three chisels should work at upto 600 mm thick

You can do this with plug and feathers if you drill holes as deep as you can get and approx 100 -150mm apart along the line you need to split and down each side the plug and feathers act as a wedge, you tap them in one by one till they go tight ish then tap them in turn, the sound will change as you are doing it you should get the same sound from each plug, getting slightly higher as you tap them, then before you know it, the block will split, I have actually used three or two cold chisels in the same hole you will need a few but it’s the same principle and the results are the same