There are several problems in your code.
First the big ones:

You are creating a new figure and a new axes in every iteration of your loop →
putfig = plt.figure
andax = fig.add_subplot(1,1,1)
outside of the loop. 
Don’t use the Locators. Call the functions
ax.set_xticks()
andax.grid()
with the correct keywords. 
With
plt.axes()
you are creating a new axes again. Useax.set_aspect('equal')
.
The minor things:
You should not mix the MATLABlike syntax like plt.axis()
with the objective syntax.
Use ax.set_xlim(a,b)
and ax.set_ylim(a,b)
This should be a working minimal example:
import numpy as np
import matplotlib.pyplot as plt
fig = plt.figure()
ax = fig.add_subplot(1, 1, 1)
# Major ticks every 20, minor ticks every 5
major_ticks = np.arange(0, 101, 20)
minor_ticks = np.arange(0, 101, 5)
ax.set_xticks(major_ticks)
ax.set_xticks(minor_ticks, minor=True)
ax.set_yticks(major_ticks)
ax.set_yticks(minor_ticks, minor=True)
# And a corresponding grid
ax.grid(which="both")
# Or if you want different settings for the grids:
ax.grid(which="minor", alpha=0.2)
ax.grid(which="major", alpha=0.5)
plt.show()
Output is this: