thread join() not stopping

Here is a simple piece of thread code.
When i add the print (or other) function into the run method--the thread
fails to stop after 2 seconds which the join(2) should ensure.
I have a function that I must have timeout and cannot figure a way to do
this.

Any help appreciated. Should compile on 2.4

Bryan

import time
from threading import Thread

class MyThread(Thread):

def __init__(self,mybignum):

Thread.__init__(self)

self.mybignum=mybignum

def run(self):

for l in range(10):
for k in range(self.mybignum):
res=0
for i in range(self.mybignum):
res+=1
#########################################
print "not stopping"
##########################################

def myadd_nothread(bignum):

for l in range(10):
for k in range(bignum):
res=0
for i in range(bignum):
res+=1
for l in range(10):
for k in range(bignum):
res=0
for i in range(bignum):
res+=1

def thread_test(bignum):
#We create 2 Thread objects for the 2 threads.
thr1=MyThread(bignum)
thr2=MyThread(bignum)

thr1.start()
thr2.start()

thr1.join(2)
thr2.join(2)
def test():

bignum=150
#Let us test the threading part

starttime=time.clock()
thread_test(bignum)
stoptime=time.clock()

print "Running 2 threads took %.3f seconds" % (stoptime-starttime)

#Now run without Threads.
starttime=time.clock()
myadd_nothread(bignum)
stoptime=time.clock()

print "Running Without Threads took %.3f seconds" % (stoptime-starttime)
if __name__=="__main__":

test()