[TxCajun]

Taking the suggestions noted above, I did a little research on nail sizes and found that a 60D nail is about the right size. However, they do come with different head sizes/shapes. The best one that I found was at the orange big depot store, called a 60D PoleBarn Nail (the one on the right in the pictures). Welding these in from the bottom should work well for me.

However, if you have already finished and painted your floor, and cringe at the idea of welding on it, you might consider a Socket Head Shoulder Screw, 1/4 diameter, 1/4 long, 10-32 thread. This could be inserted in a hole in the floor and secured with a locking nut from below.