  We prove by explicit construction that there exists a maximal slicing of the
Schwarzschild spacetime such that the lapse has zero gradient at the puncture.
This boundary condition has been observed to hold in numerical evolutions, but
in the past it was not clear whether the numerically obtained maximal slices
exist analytically. We show that our analytical result agrees with numerical
simulation. Given the analytical form for the lapse, we can derive that at late
times the value of the lapse at the event horizon approaches the value
${3/16}\sqrt{3} \approx 0.3248$, justifying the numerical estimate of 0.3 that
has been used for black hole excision in numerical simulations. We present our
results for the non-extremal Reissner-Nordstr\"om metric, generalizing previous
constructions of maximal slices.
