Issue 4, Spring 2012 - Riverland Community College

Fabricating a Master Key
We decided to remove a door lock, take it home, take it apart, and fashion a master key. So, following the
instruction sheet from the box, we removed a door lock. We didn't think it would be that noticeable since some
doors still needed locks installed. Anyway, we would bring the lock back as soon as we were finished with it.
We took the lock to a basement workshop in one participant’s home. We were careful in setting up the workbench
because we knew the pins in the lock had to be maintained in their original order if the lock were to be usable after we
were finished. It was also important that the key we were making would work in the other locks at the college. We used
a small notebook to record the order of the pin holes and pin lengths as each was extracted. Loops of masking tape,
adhesive side up, kept the pins in order, one strip for each pin hole.
We removed the lock cylinder from the external knob and carefully moved a metal slide covering the pin holes just
enough to reveal the first hole. The spring was now visible and was removed. The pins had to be retrieved in their correct
order, so we tipped the cylinder sideways just enough so that the top-most pin came out. We measured the pin with a
micrometer, recorded its length in the notebook, and then added it to the strip of masking tape. By recording the pin's
length, we could still put the lock back together correctly even if we accidentally dropped several. We continued in that
fashion until all pins were removed.
While removing the pins from the sixth hole, we encountered something unexpected. After the first couple of pins, three
tiny ball bearings fell out. We didn't know what they were for and set them aside for the time being. All we knew was
they had to go back in the same pin hole they came out of and in the same order. At this point in time, we didn't fully
understand all the features of the lock which I will explain later.
Each pin hole had a spring on top, one or more ordinary pins in the middle, and a key pin with a conically shaped nose
on the bottom that fell into the key slots. We knew that a master key meant some or all of the slots had multiple pins,
which also meant there was more than one break line for the pins: an individual key break line and a master key break
line. By “break line,” I mean a separation between pins in each hole that aligns with the interface between the inner and
outer cylinder such that no pin prevents the inner cylinder, called the “plug,” from turning.
We had purchased key blanks for that make and model from the Sterling Benjamin Franklin. We inserted a blank key
into the inner cylinder, inserted a small punch into the pin hole, and tapped it lightly with a small hammer. This made a
small indentation on the key blank indicating where the key slots were centered. The key was removed and the first slot
filed until the top of the key pin was level with the top of the plug. We added another pin and continued to file the slot
until the master key break was even with the top of the plug.
We proceeded in this fashion until the first four key slots were complete. There were additional pins (plus ball bearings)
in the fifth and sixth pin holes. That meant there were additional break lines for those holes, which meant there were
several possible configurations for the master key.
We proceeded to make one of the master key configurations by filing the fifth and sixth key slot. After each filing, we
went back to the college to test it. There was no way we could determine the correct configuration from the single lock
we had. We didn't need to go inside. Any outside door would work for the test. The first attempt failed. However, the
second succeeded! We put the lock back together, went back to the college, and used our new master key to get in
through an external door. We re-installed the lock on the door from which we had removed it and left. Participant 2, who
was mechanically inclined and had access to metal working tools, fashioned a tool that opened the utility tunnel doors
from the classroom side.
So now we had a master key which could open any door to the building. What to do with it? Best to do nothing at all
until an unusual situation presents itself. Participant 2 had graduated from Austin State Junior College the prior spring
and was off to the University of Minnesota in the fall.
Fall quarter began, the first in the brand new building. It was a wonderful facility after the years on third floor of the high
school.
Chemistry instructor Rex Sala recalls . . .
“When I joined the faculty in September of 1965, Austin Junior College was a very nice, two-year liberal arts
college whose students, for the most part, transferred to other four-year colleges and universities. Our students
generally increased their grade-point averages upon transfer due to the rigor of our curriculum. The college
offered a secretarial program that was the only vocational program we had at that time. We also provided the
college courses needed by the Albert Lea three-year Registered Nursing program. A few business courses were
offered in connection with a DECA program, but no specific two-year degree. The vast majority of the
curriculum was standard liberal arts courses. The college was in the throes of being taken over (purchased) by
the state of Minnesota. (The state had made a commitment that there should be an institution of higher
education within thirty-five miles (commuting distance) of every student in the state.
“Prank” continued on Page 7
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