The steady rest can be used with the riser blocks in place by using the steady rest riser block to bring it up to the same height as the headstock and tailstock. An example of where it might be used would be in turning a large diameter part that has a long shaft that needs to be steadied to keep it from wobbling or for those who leave their riser blocks in place all the time yet still need to center drill small stock.
The steady-rest riser is clamped to the dovetailed steel lathe bed. The steady rest is then clamped to the raised dovetail on the riser block to return it to center. The split clamp design allows it to be installed and removed very quickly.