My wife loves these windmills, wind catcher type devices in our garden. But our ground was hard, and it's difficult to drive a 3/4 inch post into the ground without first drilling a hole for it. This long 5/8" masonry bit is great for pre-drilling a hole before installing a block of wood. sit on top of the supporting part of the column and drive into the ground. I already had a 1/4" long masonry bit which I used to pre-drill holes for the three spikes sticking out of the post.