I've got one of those cheapie tire machines. Don't know what brand it is 'cause I bought it at a swap meet about 20 years ago. It looks just like the HF model shown below though. I want to put 4 anchors in the middle of my concrete shop floor that I can use to bolt this to when I need to use it. BUT, 99.99% of the time I won't want it there. So I need a way to put bolts into the anchors but not have the bolt heads stick up where I would trip on them. If there're no bolts in the empty anchors in about 3 days the holes will be full of dirt/grit and no bolt would ever go into the anchor again. I've had this thing bolted to a pallet ever since I bought it, but I need the floor space and want to get it off of the pallet. I'm thinking if I had a masonry drill bit larger than the bolt head (and appropriate sized socket) I could just countersink the bolts down into the concrete to where the bolt head is flush with the surrounding concrete. Unfortunately I don't have any such animal and don't really want to put out the ca$h to buy one to countersink 4 holes. Anyone got any better suggestions than buying a drill bit?