"to nail down" in Spanish

Context examples for "to nail down" in Spanish(!) These sentences come from external sources & may not be accurate. Therefore, we are not responsible for their content.
see if you can nail him down on this issue
a ver si logras que te dé una respuesta concreta sobre este asunto
we must nail them down to a precise date
tenemos que hacer que se comprometan a una fecha concreta
to nail down
establecer con certeza
to nail down
asegurar con clavos