Hi All - I was given a 1990's AT&T single slot pay phone - and of course no keys. Found a t-key - but had to resort to drilling out the lock for the coin box - haven't done the one for the housing yet. Anyway - so a steady slow hand and reverse/forward worked well - used titanium bits with oil - most got destroyed - but found by starting with a small bit that fit within the lock and working our way up it went a lot faster - less than two hours. And kept the lock opening in tact with no damage. A local locksmith said he could replace the locks.
Please be sure to drill only into the lock a depth of no more probably and an inch - we not knowing, drilled into the coin box. We also used tweezers etc. to remove tumbles, pins, etc. And Success! I got $2! I'll be attempting the housing lock soon - need to replace some titanium bits - but they worked well with the brass housing for the coin box key.