Stanley Sargent and Greenleaf 6730 User manual

Sargent and Greenleaf
Mechanical Safe Lock Guide

Sargent and Greenleaf is a company dedicated to providing security. Not just a sense of secu-
rity, but real security designed to meet real-world needs. We offer mechanical locks that deliver an
unbeatable combination of quality and value. Our track record of building first rate mechanical locks
stretches over 150 years. Since 1857, Sargent and Greenleaf has provided innovative security solu-
tions to financial institutions, businesses and governments across the globe. Today, we’re able to
provide a measure of protection that no one else can match.
Contents
Mounting Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Operating/Changing Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Combination Lock Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Troubleshooting/Dialing Diagnostics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

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© Copyright 2006, Sargent & Greenleaf, Inc.
THIS STEP APPLIES ONLY TO THE 6735, WHICH
IS EQUIPPED WITH AN ALUMINUM SPINDLE TUBE:
Insert the aluminum tube through
the spindle hole in the safe door,
and hold the lock against the safe
door’s mounting plate. Mark the tube
7/64" out from the front surface of
the safe door. Remove the lock and
cut the tube at your mark. Make sure
the cut is straight and smooth, and
remove any sharp edges, burrs and
cutting debris.
1. Using your fingers, pull the lock bolt to the fully extended
position. It should project approximately 1/2" from the lock
case when fully extended.
2. Remove the two Phillips
head cover screws.
3. Remove the lock cover
and set it aside.
4. Remove the drive cam
and set it aside.
5. Align the spindle hole of the lock case with the spindle hole
of the safe door and securely fasten the lock to the safe’s
mounting plate by installing a 1/4 x 20 machine screw at
each corner of the lock case.
6. Seat the Delrin bushing into the
back of the dial ring, and, using
two 8-32 machine screws, install
the dial ring to the front
of the safe door. Align the hole in
the center of the ring as closely as
possible with the spindle hole in
the door. NOTE: If the lock is equipped with a tube, the dial
ring bushing will seat over the end of the tube.
7. Insert the dial’s spindle through the safe door and lock.
Thread the spindle into the drive cam until the lock dial is
snug in its ring and the drive cam is snug against the wheel
post of the lock. Mark the spot where the spindle first projects
through the drive cam.
8. Remove the spindle
from the lock, thread
the drive cam onto
the spindle until it
is between the dial
and your mark. Cut
the spindle at your
mark, then file the new spindle end until it is smooth and
flat. Remove the drive cam from the spindle to re-form any
threads, which may have been damaged in the cutting pro-
cess.
9. Insert the dial’s spindle through the safe door and thread it
into the drive cam until snug. The end of the spindle should
now be nearly flush with the surface of the drive cam.
10. Back the cam off the spindle enough to align the slot
(spline keyway) in the spindle with the slot in the drive
cam, which corresponds to the
mounting position of the lock
(RH, LH, VU, VD). If less than
1/2 turn is required to align
the spline keyways, back the
cam off one extra revolution.
11. Insert a new, unused spline key
into the aligned spindle and drive
cam slots. The flag of the spline
key should extend over the body of
the drive cam and NOT cross the
end of the spindle. Using a small,
light hammer, tap the spline key
until the flag just touches the
surface of the drive cam. Make certain the spline key is a
tight friction fit, or the lock will not function properly.
12. Replace the lock’s cover and fasten it securely with the
cover screws.
13. Refer to operating and changing instructions for the model
of lock you have installed.
Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Mounting Instructions

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© Copyright 2006, Sargent & Greenleaf, Inc.
READ THESE INSTRUCTIONS THOROUGHLY
BEFORE OPERATING THE LOCK OR ATTEMPTING
TO CHANGE THE COMBINATIONS
Note: To assure proper operation, all combination safe locks
should be serviced by a qualified safe technician annually;
more often if used in a hostile environment (dust, dirt, high
humidity, etc.).
The dial ring for your lock has
two index marks (Figure 1).
The one located at the twelve
o’clock position is the opening
index. Numbers on the dial are
aligned with this index to open
the lock.
The mark at the eleven o’clock
position is the changing index.
It is aligned with numbers on the dial only when preparing the
lock for insertion of the changing tool and when entering new
numbers to install a new combination.
DIALING TIPS:
1. When performing any dialing operation, always view the dial
straight-on (Figure 2).
2. If you turn past a number you meant to stop on, you cannot
back up to it. Start the entire dialing procedure again, from
the very beginning. This is especially critical when changing
the lock’s combination.
3. In dialing instructions, left is counterclockwise and right is
clockwise.
4. Each time the desired number of the dial
comes into alignment with the index being
used, it is counted as a turn of the dial. For
instance, if the dial is set with 45 aligned to
the opening index and the next number to be
entered is 40, rotating the dial immediately
left (counterclockwise) to 40 is considered
one time left to 40.
5. Never force the dial. A dial which cannot be turned with
light-to-moderate hand pressure indicates the lock is open
or that the mechanism needs to be serviced by a qualified
safe technician.
TO OPEN:
Your lock may be set on a factory shipping combination, or it
may be set on a true, three-number combination. To open a
lock set on a factory shipping combination, turn the dial left
until 50 aligns with the opening index the fourth time. Now
turn the dial right. It should stop at about 95, indicating the
lock bolt has been retracted.
In some cases, even though your lock was factory set at 50, it
will open when dialed left at least four times to 41 then turned
right until the dial stops at about 86 or 87. This is because
your lock is paired with a dial that has its spindle spline
keyway set to 41 rather than what has historically been the
standard spline orientation of 50 for the spindle spline. If your
factory set lock does not open on 50, it will undoubtedly open
on 41.
If your lock is set on a true, three-number combination, follow
these steps to open:
1. Turn the dial left until the first number of the combination
( ) aligns with the opening index the fourth time.
2. Turn the dial right until the second number of the combination
( ) aligns with the opening index the third time.
3. Turn the dial left until the third number of the combination
( ) aligns with the opening index the second time.
4. Turn the dial right until it stops, at approximately 95. If the dial
does not stop, carefully repeat the entire opening procedure.
Remember to dial exactly to the number of the combination
with which you are working. Dialing even a small amount past
a number you meant to stop on will cause the lock to remain
locked. This is part of the mechanism’s security.
5. To re-lock the combination lock, turn the dial four complete
revolutions to any non-combination number.
Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Operating/Changing Instructions
Figure 2
Figure 1

PREPARE FOR COMBINATION CHANGE:
1. Compare your changing tool to Figure 3. Only a tool which
very closely matches the outlined portion of the drawing
should be used (the handle section may have a slightly
different bend or length). Use of an incorrect tool will likely
cause the lock to malfunction.
2. NEVER insert a changing tool into the lock unless the lock’s
cover is in place.
3. It is advisable to cover the opening index with a small piece
of opaque tape to avoid aligning any numbers with it during
the combination changing procedure.
4. All changing operations are performed with the safe door
open. THE SAFE DOOR SHOULD NEVER BE CLOSED UNTIL THE
NEW COMBINATION IS SUCCESSFULLY TRIED AT LEAST THREE
TIMES!
SELECTING A NEW COMBINATION:
Observing the following rules will help you select a new com-
bination which is secure and which will optimize the design
strengths of your Sargent & Greenleaf lock.
1. Do not select numbers which all end in “0” and “5.” An
example of a poor combination is: “50 – 15 – 30.” An example
of a good combination is: “52 – 15 – 37.”
2. Do not select numbers in an ascending or descending
sequence. An example of a poor combination is: “22 – 41 –
68.” An example of a good combination is: “22 – 68 – 41.”
3. Leave at least a ten number margin between adjacent numbers
of the combination. An example of a poor combination is:
“41 – 39 – 66.” An example of a good combination is:
“41 – 30 – 66.”
4. Do not use a number between 95 and 99 or between 0 and
20 for the third (or last) number of the combination. This
can cause a condition which will inhibit the mechanism
from locking correctly.
5. Avoid using easily guessed numbers (birth dates, house and
phone numbers, etc.).
IF YOUR LOCK IS SET ON THE
FACTORY SHIPPING COMBINATION:
Turn the dial left until the number 50 aligns with the changing
index the fourth time. Go directly to the step titled “INSERT THE
CHANGING TOOL.” If the changing tool does not go into the lock
all the way, substitute 41 for the factory shipping combination.
IF YOUR LOCK IS SET ON A TRUE,
THREE-NUMBER COMBINATION:
1. Turn the dial left until the first number of the combination
aligns with the changing index the fourth time.
2. Turn the dial right until the second number of the combination
aligns with the changing index the third time.
3. Turn the dial left until the third number of the combination
aligns with the changing index the second time.
INSERT THE CHANGING TOOL:
The profile of both the changing tool and the opening in the
lock’s cover allow the tool’s insertion only when aligned cor-
rectly. It may be necessary
to wiggle the changing tool
slightly in order to insert it
to the point where the tool’s
wing (Figure 3) is entirely
inside the lock case. Do not
attempt to turn the changing tool until the wing is completely
inserted. Once this is accomplished, rotate the key approxi-
mately 90º counterclockwise
(the only direction in which
it will turn). A definite
release of tension inside the
lock will be felt (Figure 4).
ENTER THE NEW
COMBINATION:
1. Turn the dial left until the first new numbers aligns with the
changing index the fourth time.
2. Turn the dial right until the second new number aligns with
the changing index the third time.
3. Turn the dial left until the third new number aligns with the
changing index the second time.
4. Turn the dial right approximately ten numbers.
If you feel you have made any errors, however small, in the
changing procedure, begin again with the first step in this section
(“ENTER THE NEW COMBINATION”). Rotate the changing tool
approximately 90º clockwise and remove it from the lock.
Note: Do not pull outward on the changing tool until it has been
fully rotated to the same position as when you first inserted it.
Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Operating/Changing Instructions
Figure 3
Figure 4
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© Copyright 2006, Sargent & Greenleaf, Inc.

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© Copyright 2006, Sargent & Greenleaf, Inc.
CHECK THE NEW COMBINATION:
Uncover the opening index and check your new combination by
following these instructions, which are identical to those under
“TO OPEN.”
1. Turn the dial left until the first number of the new combina-
tion aligns with the opening index the fourth time.
2. Turn the dial right until the second number of the new com-
bination aligns with the opening index the third time.
3. Turn the dial left until the third number of the new combina-
tion aligns with the opening index the second time.
4. Turn the dial right. It should come to a positive stop in
less than one revolution. If the dial does not stop, carefully
repeat the entire opening procedure at least two more times
before either calling a qualified safe technician or referring
to the “…in case of trouble” section.
5. A combination change should be considered successful only
when the new combination is successfully tried at least three
times. Only then is it wise to close and lock the safe door.
…in case of trouble
Anyone can make mistakes and “lose” a lock’s combination in
the process of changing to a new set of numbers. This section
will detail two steps you can take on your own to manually pre-
pare the lock for a second attempt to enter a new combination.
If you still cannot set a combination into the lock by following
these procedures, call a reputable safe technician to correct
the problem and service the lock. DO NOT CLOSE THE SAFE
DOOR BEFORE THIS SERVICE IS PERFORMED.
PROCEDURE #1:
If the lock will not open when the new combination is dialed
to the opening index, cover the opening index and dial the new
numbers to the changing index. For example:
1. Turn the dial left until the first new number aligns with the
changing index the fourth time.
2. Turn the dial right until the second new number aligns with
the changing index the third time.
3. Turn the dial left until the third new number aligns with the
changing index the second time.
Once this is done, attempt to re-insert the changing tool into
the lock. Although it’s acceptable to wiggle the tool slightly,
do not force it. If the key will enter the mechanism to the point
where the wing is entirely inside the lock case, you may turn
the changing tool approximately 90º counterclockwise and proceed
with the steps listed under “ENTER THE NEW COMBINATION.”
PROCEDURE #2:
These steps should only be taken after unsuccessfully trying
Procedure #1 and inspecting the area of the lock for attach-
ments to the lock case. If any part of the safe is attached to
or bears against any part of the lock’s cover, refer servicing
to a qualified technician and do NOT proceed.
1. Remove the two 8-32 machine screws from the cover and
carefully lift the cover from the lock. Place the screws and
cover aside. Refer to Figure 5 for steps 2, 3, and 4.
2. Use a blunt probe (screwdriver, unsharpened pencil, etc.)
in the opening in the outer edge (gate) of the top wheel to
rotate this wheel until it aligns with the gate in the edge
of the wheel below the top wheel. See Figure 5 to help iden-
tify features.
3. With the probe in the gates of both wheels, move them
together to align the two gates with the gate in the bottom
wheel. Now you will be moving all three wheels together.
4. Move all wheels counterclockwise (as viewed from the inside
of the lock) until the probe catches in the hook of the lever
nose. At this point, carefully remove the probe, being very
careful to maintain all three wheels in alignment.
5. Replace the cover on the lock and attach it with the two
machine screws.
6. You should now be able to insert the changing tool, although
it will probably be necessary to wiggle it more than usual.
Do not force the changing tool. Once it is inserted to this
point where the wing is entirely inside the lock, turn the
changing tool approximately 90º counterclockwise and proceed
with the instructions under “ENTER THE NEW COMBINATION.”
WARNING : DO NOT REMOVE ANY INTERNAL LOCK PARTS.
THIS IS A PRECISION MECHANISM WHICH SHOULD ONLY BE
SERVICED BY A QUALIFIED SAFE TECHNICIAN.
Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Operating/Changing Instructions
Figure 5

COVER SCREW: machine screws
used to attach the cover to lock case;
typically 8-32.
COVER: the cover for the lock case;
the wheel post is attached to or cast
as a part of some model covers (6650
& 6709 – both obsolete).
LOCK CASE: the housing into
which all component parts are
installed or attached; the case casting includes several important
bearing surfaces and features.
MOUNTING SCREW: used to attach the lock to a
safe door; typically 1/4 X 20 size.
TUBE: surrounds and protects the spindle from insulation,
etc., and is pressed onto the tube horn; the tube connects and
coordinates the dial ring with the case
and components of the lock.
TUBE HORN: a cast feature of the
case to which the tube is attached (not
used in all locks).
TUBE NUT: a hexagon nut used to attach the dial
ring to the tube (not current production).
DIAL: the component which allows a user
to position the wheels of the lock and oper-
ate the bolt when proper wheel alignment is
achieved; each division on the dial represents
a possible combination setting for
each wheel.
KEY LOCKING DIAL: a dial that can be
locked with a key to prevent rotation.
OPENING INDEX: the index on the dial ring used when dial-
ing the combination to open the lock; commonly referred to as
the “crows foot”.
CHANGING INDEX: the index on the dial ring used when
changing the combination; on S&G locks, it is 8 1/2 numbers
to the left of the opening index.
L.O.B.C. INDEX: L.O.B.C. means
the lock cover is “Locked On By
Combination”; the opening combina-
tion must be dialed to this index to
remove the lock cover and/or change
the combination.
DIAL RING BEARING: a plastic component which fits into
a depression in the center of a dial ring;
it acts as a bearing surface for the dial.
KEY LOCKING
DIAL RING: a
dial ring containing a key lock, which
throws a bolt into the underside of the
dial to prevent rotation.
SPY PROOF
DIAL & RING:
restricts unau-
thorized observation while dialing the
combination (as opposed to a front-
reading dial and ring).
DUST COVER: a
clear plastic shield to keep fingerprints off
the dial and dial ring so that fingerprint
segments cannot later be realigned and the
numbers of the combination be discovered;
at one time, it was required on all G.S.A.-
approved security containers.
Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Combination Lock Glossary

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© Copyright 2006, Sargent & Greenleaf, Inc.

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© Copyright 2006, Sargent & Greenleaf, Inc.
WHEEL: an assembly, usually in the form of a circular disc,
having a gate and drive pin whose locations may be set to
selected positions to permit the
user to change the combination.
GATE: the cutout in the periphery
of the wheel that is engaged by
the fence on the lever assembly.
DRIVE PIN: a pin extending from the underside of the drive
cam and from all but the #1 wheel in
a wheel pack; it transfers motion to
the next component in the wheel pack.
WHEEL PACK: a set of wheels, fly and
isolation (spacing) washer supported by
a torque adjuster or tension washer and
secured with a retainer.
WHEEL POST: a component, cast as part of
the lock case or cover, on which the wheel
pack is assembled and about which the
wheels rotate (a bearing surface).
WHEEL, KEY CHANGE: a component
containing both an inner and outer hub
with meshing teeth; when disengaged
by a key, the hubs’ relationship may be
changed to a selected number by dialing.
KEY CHANGE WHEEL CONSTRUCTION: a change key is
inserted and turns the cam, which disengages the arm teeth
from the inner hub to permit changing the combination.
WHEEL NUMBER: each combination lock wheel is desig-
nated by a number, indicating which number of the combination
it corresponds to; the first wheel contains the first number of
the combination, the second wheel contains the second number
of the combination, and the third wheel contains the third
number of the combination; in a three-wheel lock, the third
wheel is always adjacent to the drive cam.
X-RAY PROOF WHEEL: the outer area of the wheel where
the gateway is located (the wheel case) is made of Nylon, Lexan,
Delrin or Celcon to prevent X-ray methods of determining the
combination of the lock.
Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Combination Lock Glossary

FLY: a part which is
contacted by the drive pin
of an adjacent drive cam or
wheel to impart motion to the
wheel on which it rides; flys can be either fixed or movable.
DRIVE CAM: a circular component, which
is connected directly to the spindle; its drive
pin transfers rotation to the wheels, and its
gate is shaped to accept the lever nose.
CONTACT POINTS: the
numbers which come under
the opening index when the
nose of the lever contacts
the sides of the gate in the
drive cam; the left contact
area is detected by turning
the dial to the right, and the
right contact area is
determined by turning the
dial to the left.
S&G 8550 MP CAM: a drive cam fitted
with a roller to push the lever/accelerator
spring assembly onto a shelf, preventing
lever/wheel contact.
S&G 8400 MP CAM
(SLIDE CAM): a drive cam
which incorporates two slid-
ing components; in the closed
position, the drive cam’s gate is
concealed by one of the sliders.
SPINDLE: a threaded rod,
which connects the dial and
drive cam.
SPLINE KEY: a press-fit part which is
inserted into the aligned spindle and cam
spline keyways, effectively tying the spindle
and drive cam together, making them one
functional part.
INNER SPINDLE: a component of
the S&G manipulation-proof series; it
connects the “butterfly” knob with the
device which actuates the cam slide.
KNOB: component of the S&G 8400
series combination locks which is
connected with the inner spindle
assembly; when turned, it actuates
the cam slide.
SPACING/ISOLATION WASHER: a thin
spacer used between the wheels; its purpose is
to isolate the wheels from each other.
TENSION WASHER (SPRING): a spring
washer used to apply pressure on the wheel
pack (used in NTA locks).
RETAINING WASHER: a part which retains the wheel pack
on the post; it can be wire-formed in a circle,
or a “Spirolox” washer.
LEVER: serves to retract the bolt when
proper combination has been dialed.
1. Fence – a part of the lever that fits
into wheel gates, permitting the lever
nose to engage in the drive cam.
2. Nose – a portion of lever body which
contacts the drive cam.
3. Bushing – integral part of the lever formed to hold the lever
spring in place and through which the lever screw holds the
lever to the lock case.
Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Combination Lock Glossary
SPLINE
KEYWAY
STRAIGHT
THREADS
CAVITY IN DIAL TO
ACCEPT SPINDLE
NOSE
BUSHING
FENCE
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© Copyright 2006, Sargent & Greenleaf, Inc.

LEVER SCREW: a brass screw which attaches the
lever to the bolt, and acts as a pivot for the lever and
a travel stop for the bolt.
LEVER SPRING: a stainless steel spring (in S&G
locks) which applies directional tension to the lever
or roller fence.
LEVER STOP: a molded portion of the lock
case which prevents the lever from moving to
the unlocked position while the lever is held
out of the drive cam gate by the fence resting
on the circumference of the wheel pack.
S&G 8550 LEVER ASSEMBLY: the attached accelerator
spring provides the downward force
required to engage the lever with the
cam and wheel gates for opening.
BOLT: a blocking bar connected to the
lever screw; it can be retracted when
the proper combination
is dialed.
BALL DETENT: a spring-loaded steel ball (3/16")
that partially engages a cavity in the underside of
the bolt when extended to the locked position; it acts
with the travel stop components to ensure proper
positioning of the bolt.
GATE COVER: prevents the lever
from entering the gates of the zero
change locks while the combination
is changed; also prevents insertion of
the change key until the wheels are
aligned properly.
COMBINATION CHANGE KEY:
a tool used in resetting a key
change wheel.
DOOR THICKNESS: the dimension from the lock
mounting surface on the inside of the door to the front
face of the door.
RELOCK TRIGGER: a com-
ponent located inside the lock
case which prevents the bolt from
retracting in the event the lock
cover is separated from the lock.
THERMAL RELOCKING COMPONENT:
a small tab of soft, low melting point material,
used to activate the relock trigger when the
lock is attacked by heat; its melting tempera-
ture is approximately 165ºF.
HAND OF COMBINATION LOCK: the
orientation of the combination lock within
its mounting; the hand is indicated by the
location of the combination lock bolt.
Vertical Up – bolt is pointing up
Vertical Down – bolt is pointing down
Right Hand – bolt (viewed from back of lock) points right
Left Hand – bolt (viewed from back of lock) points left
CLASSIFICATION: combination locks are classified by
Underwriters Laboratories (in Standard for Safety # UL 768)
as Group 1, Group 1R, or Group 2.
GROUP 1: Those locks that have a high degree of resistance
to expert or professional manipulation. The protection against
professional manipulation includes advanced design features
not found in conventional designs.
GROUP 1R: Those locks that have a high degree of resistance
to expert manipulation and are designed to prevent surreptitious
entry by means of x-ray imaging.
GROUP 2M: Those locks that have a moderate degree of resis-
tance to unauthorized opening, and have passed a two-hour
manipulation resistance test.
GROUP 2: Those locks that have a moderate degree of resistance
to unauthorized opening.
LEVER
SCREW
HOLE
BALL
DETENT
CAVITY
CAVITY FOR END
OF LEVER SPRING
CUTOUT FOR
RELOCK TRIGGER
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© Copyright 2006, Sargent & Greenleaf, Inc.
Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Combination Lock Glossary
SAFE LOCK
VAULT LOCK

Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Troubleshooting/Dialing Diagnostics
A guide to solving safe lockouts through
knowledge, rather than force
Lockout Diagnostics
Between 80 and 90% of all safe lockouts can be overcome
without the need to penetrate a safe. A combination lock is a
finely tuned mechanical puzzle whose answer is known only to
those who possess the combination and can use it to correctly
and precisely align internal parts of the lock. Unfortunately,
even the tiniest misalignment of components can (and often
does) change the answer to the puzzle, or simply make the
puzzle more difficult to solve.
ProPer DiaLing technique
A very high percentage of lockouts are due to the end user’s
improper dialing of the combination lock. There is a simple,
definite procedure which must be followed to achieve consis-
tent success. An important point to remember is that there are
usually two index lines on a dial ring. The one at the twelve
o’clock position is used in dialing open the lock. The mark at
the eleven o’clock position (if present) is used only for chang-
ing the combination.
While performing any procedure involving dialing numbers into
the lock, it is important to view the dial and ring straight on.
This helps ensure the number you are entering will be aligned
directly under the index mark. If you dial past the intended
number even slightly, begin the entire dialing procedure again.
The procedure for a Sargent & Greenleaf three-wheel lock is
as follows:
1. Turn the dial left (counterclockwise), stopping the fourth
time the first number of the combination aligns with the
opening index.
2. Turn the dial to the right (clockwise), stopping the third
time the second number of the combination aligns with the
opening index.
3. Turn the dial to the left (counterclockwise), stopping the
second time the third number of the combination aligns
with the opening index.
4. Turn the dial to the right. Some resistance should be felt
as the mark representing “5” comes under the opening
index, and the dial should reach a positive stop near “95.”
The lock is now open, and any other action necessary to
open the safe should be performed.
During the dialing process, it is normal to feel more resistance
each time the dial is turned a complete revolution. Each turn
of the dial engages another part of the mechanism, creating
more resistance to dialing.
The procedure for a Sargent & Greenleaf four-wheel lock is as
follows:
1. Turn the dial to the right (clockwise), stopping the fifth
time the first number of the combination aligns with the
opening index.
2. Turn the dial left (counterclockwise), stopping the fourth
time the second number of the combination aligns with the
opening index.
3. Turn the dial to the right (clockwise), stopping the third
time the third number of the combination aligns with the
opening index.
4. Turn the dial to the left (counterclockwise), stopping the
second time the fourth number of the combination aligns
with the opening index.
5. Turn the dial to the right (clockwise). Some resistance
should be felt as the mark representing “5” comes under
the opening index, and the dial should reach a positive
stop near “95.” The lock is now open, and any other action
necessary to open the safe should be performed.
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© Copyright 2006, Sargent & Greenleaf, Inc.
Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Troubleshooting/Dialing Diagnostics
MisaLigneD DiaL ring
The number one cause of lockouts is a misaligned dial ring. The
ring provides a critical bearing surface for the dial, and the two
parts must be aligned correctly. The ring has two elongated
screw holes for attachment to the safe door. The elongated
holes allow the safe manufacturer to make the best possible
alignment of parts. The negative aspect of the elongated screw
holes is illustrated when the ring or dial is bumped, and is
allowed to move within the limits of the mounting screw holes.
The surest way to prevent movement of the dial ring is to install
the ring using the screws in the elongated holes, check for
smooth operation of the dial, then remove the dial and insert
a pin or machine screw through one of the two circular screw
holes in the ring. A hole will need to be placed in the safe door
to accommodate the additional fastener.
Let’s assume this extra step was not taken, and the dial has
shifted from its original position. This situation can manifest
itself in two ways. The following symptoms can occur sepa-
rately or together.
BinDing DiaL
The dial binds against the ring constantly or in one or more
areas as the dial is turned. This problem is easy to correct. You
will notice that the dial doesn’t sit squarely in its ring when
viewed from top, bottom or one of the sides. In certain dial/
ring configurations, you may notice a larger gap between the
two components at some spot on the dial. Use a light plastic
or rawhide mallet (or even a screwdriver handle) to tap the dial
ring directly adjacent to the point where the dial rides lower
in the ring, or adjacent to the widest gap between the dial
and ring. Tap lightly, and NEVER strike the dial, only the ring.
Adjust the position, check for smoothness of dial movement,
and make further adjustments as necessary. If a high spot or
gap isn’t apparent, just tap lightly around the circumference
of the ring until the dial rotates smoothly.
shifteD DiaL ring
If the dial ring is bumped, or if the mounting screws become
loose, the elongated mounting holes allow the ring to rotate
slightly. Anytime the dial ring moves, the opening combina-
tion of the lock also changes. For instance, if the dial ring
shifts right (clockwise) a distance equivalent to 3 numbers on
the dial, the opening index, which is painted on the ring, also
shifts right a distance equivalent to 3 dial numbers. Placing
the number 25 under the relocating opening index would be
the same as placing 22 under the opening index before the
ring shifted. If the dial ring has moved, it will be necessary to
add or subtract digits from the original combination numbers
to open the lock.
If the dial ring can be moved by grasping and turning by hand
(just a few degrees in either direction), the opening index has
undoubtedly shifted, causing a lockout, but lack of movement
doesn’t rule out the possibility. Fortunately, this is an easy
type of lockout to overcome.
First, make sure the ring is stabilized and will not move during
the dialing procedure; we don’t want our reference point (open-
ing index) to move. Use one or two pieces of masking tape to
tape the dial ring to the safe door. Be careful not to obscure
the opening index or tape the dial. It needs to remain free
turning. Write the numbers of the combination in a column.
Subtract 1 from each number of the combination and write the
new numbers in a column to the left of the original combina-
tion. Now, subtract 2 from each number of the original combi-
nation and write these new numbers to the left of the previous
column. Continue this process until you have subtracted 10
from each combination number. When this is completed, start
ADDING to the combination, placing the new combinations in
columns to the right of the original. Your table should look like
the example, given an original combination of 20 • 60 • 40.

Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Troubleshooting/Dialing Diagnostics
stuck fLy
So far, we’ve only checked and corrected problems with external
parts: the dial and ring. There are many more parts inside the
lock which are required to work with much greater precision.
Most locks you will encounter are three-wheel types, requiring
transmission of motion from the dial to the spindle, from the
spindle to the drive cam, from the drive cam to the number 3
wheel, from the number 3 wheel to the number 2 wheel, and
from the number 2 wheel to the number 1 wheel. While this
is a simple explanation of the transfer of motion, there are
actually more parts involved.
Note: The following procedure has nothing to do with whatever
combination numbers we assume have been set into the lock.
Before beginning our diagnostics, it will be necessary to count
the number of wheels in the lock. A good quality safe techni-
cian’s audio amplifier will make the job easier by enabling you to
clearly hear metal-to-metal contact inside the lock.
Turn the dial right (clockwise) at least six times, stopping at
60 on the last turn. Turn left (counterclockwise) to 40. As you
pass the vicinity of 6 and 14, you should feel and hear metal-
to-metal contact. This is the nose of the lever striking the
sides of the drive cam gate. The presence of these “contact
points” tells you that the lever is moving freely on its pivot,
and the lever spring is intact.
Pause at 40 to re-grip the
dial, then dial smoothly
and fairly rapidly to 70. As
you pass 60, you should
again feel light metal-to-
metal contact. This is the
drive cam picking up the
number 3 wheel (which
holds the 3rd number of
the combination) right
where you left it parked.
The contact should occur
between 60 and 62. If it occurs ten to twelve numbers before
60, the 3rd wheel fly is stuck.
Continue dialing left to 40. Once again dial smoothly to 70.
The contact you feel and hear is the 3rd wheel picking up the
2nd wheel (which holds the 2nd number of the combination).
The contact should occur within two numbers of the last con-
tact (drive cam picking up 3rd wheel). If the 3rd wheel picked
up at 60, and the 2nd wheel picks up at 50 or 51, the number
2 wheel fly is stuck.
Continue the same procedure to check the 1st wheel fly. You
should check another revolution of the dial to be sure you are
not dealing with a four-wheel lock. In that case, the wheels
would be numbered 4 – 3 – 2 – 1, with each designation refer-
ring to the number of the combination carried on the wheel.
Wheel number 4 carries the fourth number of the
combination, wheel number 3 carries the 3rd number of
the combination, and so on.
If all goes well, you might feel metal-to-metal contact on the
1st three turns of the dial, at 60 1/2, 61 and 61 1/2. The
fourth turn of the dial will reveal nothing. This most likely
means you have a three-wheel lock with properly functioning
flys. It could also mean you have a four wheel lock with a
broken drive pin on the #2 wheel, but that is very unlikely. The
point is this: Symptoms can point to more than one type of
lock malfunction.
A slightly more likely situation is to observe no metal-to-metal
contact at 60, which would mean the drive pin on the drive
cam is broken, and no motion is being transferred to any of the
wheels. Unfortunately, this calls for forced entry of the safe. A
broken drive pin is apt to be on the drive cam or the #3 wheel.
The farther a wheel is from the drive cam the less likely it is
to suffer from a broken drive pin, because it is moving fewer
other parts and is subjected to less stress.
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© Copyright 2006, Sargent & Greenleaf, Inc.

12
© Copyright 2006, Sargent & Greenleaf, Inc.
Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Troubleshooting/Dialing Diagnostics
a fLy in the ointMent
Let’s stand back for a moment, and do a quick review of wheel
construction. The travel of a movable fly is the distance the
fly can move within the confines of its milled area in the wheel
center. The amount of travel is expressed in dial numbers,
and is typically between 10 and 12. The amount of travel is
not chosen arbitrarily, but is equal to twice the width of the fly
plus the width of the associated drive pin. This is the opti-
mum amount of fly travel which will allow use of every number
on the dial in selecting a combination.
No matter where a
fly may be stuck, out
dialing diagnostics
will show the affected
wheel picking up
before it should by a
number equal to the
total possible travel
of the fly (expressed
in dial numbers). In
the case of current
production S&G locks, the number is 10. This 10 number off
pickup indicates the fly is stuck, but not where in its travel the
sticking occurs. Suppose we picked up wheels at the following
places during our dialing procedure:
1st turn 61 3rd wheel fly is okay
2nd turn 51 2nd wheel fly is stuck
3rd turn 52 1st wheel fly is okay
At first glance, you might assume the 1st wheel fly is also
stuck. However, because it picks up within 2 numbers of
where the #2 wheel picked up, we know the #1 wheel fly is
okay. Remember, as we turn the dialing procedures, try some-
thing simple. A sharp, snapping dial action whenever direc-
tion is reversed will often shove the fly to its limit, despite any
burr or debris which may be in its way. This will allow you to
use the actual combination numbers and avoid the more time
consuming procedure which follows. If snapping doesn’t work,
it will be necessary to resort to some simple math.
Chances are excellent a fly will stick at one of the extreme limits
of permissible travel, and this makes dialing open the lock
pretty straightforward. For a Sargent & Greenleaf three-wheel
lock, use the following directions for whichever case you diagnose.
Fly on wheel #1 is stuck:
Subtract 10 from the 1st combination number
Dial 2nd and 3rd number as usual
Fly on wheel #2 is stuck:
Dial 1st number as usual
Add 10 to 2nd combination number
Dial 3rd number as usual
Fly on wheel #3 is stuck:
Subtract 10 from the 1st combination number
Because most situ-
ations involve the
fly sticking at the
extreme limit of
travel, one of these
procedures will
open the lock most
of the time. After
the combination
is dialed, return to
the contact area of
the lock (between
#6 and #14) and
oscillate the dial
between the two
metal-to-metal contact points. If the internal parts of the lock
are almost lined up to allow the lever to fall and open the lock,
this vibration may finish the job for you. Anytime you are dialing
to open a stubborn lock, oscillation
of the dial in the contact area can help.
LIMITS OF FLY TRAVEL
DETERMINED BY
MILLED AREA OF
THE WHEEL CENTER
THE CONTACT AREA
IS THE WIDTH OF THE
DRIVE CAM GATE,
MEASURED IN DIAL
NUMBERS

Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Troubleshooting/Dialing Diagnostics
We add or subtract 10 from combination numbers because this
is the distance the fly can normally move in an S&G lock.
Unless you can absolutely determine that 10 is the magic
number for the lock you are working on, the following instructions
might be of more use.
Fly on wheel #1 is stuck:
Subtract “X” from the 1st combination number
Dial 2nd and 3rd number as usual
Fly on wheel #2 is stuck:
Dial 1st number as usual
Add “X” to the 2nd combination number
Dial 3rd number as usual
Fly on 3rd wheel is stuck
Subtract “X” from the 1st combination number
Dial the 2nd number as usual
Subtract “X” from the 3rd combination number
Select the appropriate dialing directions for the situation you
have diagnosed. For the 1st dialing procedure, X=8. Dial the
same procedure with X=9, then X=10, then X=11, then X=12.
One of these five values of X is likely to work.
The worst possible case is a fly stuck somewhere between the
permissible limits of its normal travel. Our diagnostics point
out which wheel contains the sticking fly and tell us the total
effect on this wheel and the next one down the transmission
path is 10. Remember, 10 is the total permissible range of fly
travel in our S&G lock. In case we forget, our dialing reveals
a 10 number difference in pickup points between a “healthy”
wheel and a sticky one.
If the fly is stuck on the #1 wheel, the fix is the easiest. Wheel
#1 is dialed left when entering the combination, so numbers
go from lower to higher as you turn the dial. A stuck fly means
motion will be transferred to the #1 wheel one to ten numbers
before normal, or 1 to 10 numbers less than the true combina-
tion number. Assuming a combination of 20 • 60 • 40, a stuck
fly on the #1 wheel can change to combination from 20 • 60
• 40 to 19 • 60 • 40. In other words, the first number of the
combination can be 10, 11, 12, 13, 14, 15, 16, 17, 18 or 19.
Dial no more than ten combinations, and the lock will open.
The #1 wheel is the final wheel in the transmission path, so
there are no more wheels to worry about. The combination
numbers set on wheels #3 and #2 are unaffected.
Things become a bit complicated when the stuck fly is on the #2
wheel, because the #1 wheel is also affected. Just keep in mind
that the total displacement of the two wheels together is 10.
The #2 wheel is dialed right when entering the combination,
and we can see that numbers go from higher to lower when we
turn the dial right. A stuck fly will cause the #2 wheel to move
before we expect it to, at a higher number than the one we set
on the lock. Again, the early contact will occur from one to ten
numbers off; this time above the set number.
We’ll continue to work with an original combination of 20 • 60
• 40. The possible numbers to try on the 2nd wheel are 61, 62,
63, 64, 65, 66, 67, 68, 69 and 70.
The 1st wheel is also affected, and since it is dialed left and
contact again occurs before we expect it, the possible numbers
for this wheel are 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20.
The key is to remember that the total displacement of the two
adjacent wheels is 10 – the maximum possible fly movement
on one wheel. Keeping this in mind, here is a list of the combi-
nations we will try. One of them will open the lock.
1st Combination 20 (20-0) 70 (60+10) 40 (unaffected)
2nd Combination 19 (20-1) 69 (60+9) 40
3rd Combination 18 (20-2) 68 (60+8) 40
4th Combination 17 (20-3) 67 (60+7) 40
5th Combination 16 (20-4) 66 (60+6) 40
6th Combination 15 (20-5) 65 (60+5) 40
7th Combination 14 (20-6) 64 (60+4) 40
8th Combination 13 (20-7) 63 (60+3) 40
9th Combination 12 (20-8) 62 (60+2) 40
10th Combination 11 (20-9) 61 (60+1) 40
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© Copyright 2006, Sargent & Greenleaf, Inc.

14
© Copyright 2006, Sargent & Greenleaf, Inc.
Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Troubleshooting/Dialing Diagnostics
Dialing ten combinations is very little work compared with
the alternative – drilling. It takes so little time that virtually
nothing is lost in the attempt to open the lock in this
nondestructive manner.
Now it’s time to figure out what we can do about a lock with a
fly stuck on the 3rd wheel. This will affect all the wheels in the
lock. To keep it simple, just think about two adjacent wheels
at a time. The 3rd wheel is dialed left when entering the lock’s
combination, which means numbers get higher as we turn the
dial. When a fly is stuck, its wheel is moved by the drive pin on
the drive cam earlier than expected, or at a lower number than
what was set on the lock. Possible 3rd wheel numbers (using
our original combination of 20 • 60 • 40) are 30, 31, 32, 33,
34, 35, 36, 37, 38 and 39. Make a chart similar to the one you
drew for the stuck fly wheel on the #2 wheel, this time filling
in possible numbers for the #3 and #2 wheels.
1st Combination
1st NO. IS NOT DETERMINED 60 (60+0) 30 (40-10)
2nd Combination
1st NO. IS NOT DETERMINED 61 (60+1) 31 (40-9)
3rd Combination
1st NO. IS NOT DETERMINED 62 (60+2) 32 (40-8)
4th Combination
1st NO. IS NOT DETERMINED 63 (60+3) 33 (40-7)
5th Combination
1st NO. IS NOT DETERMINED 64 (60+4) 34 (40-6)
6th Combination
1st NO. IS NOT DETERMINED 65 (60+5) 35 (40-5)
7th Combination
1st NO. IS NOT DETERMINED 66 (60+6) 36 (40-4)
8th Combination
1st NO. IS NOT DETERMINED 67 (60+7) 37 (40-3)
9th Combination
1st NO. IS NOT DETERMINED 68 (60+8) 38 (40-2)
10th Combination
1st NO. IS NOT DETERMINED 69 (60+9) 39 (40-1)
Now that we know where to set the 2nd and 3rd wheels for the
trial combinations, we can calculate the numbers for the 1st
wheel. Since we’re only considering two adjacent wheels at a
time, and the total pair displacement is always ten (because
this is how far a freely moving fly can travel in this lock), the
1st wheel numbers are automatically determined by what we
have already written down for the #2 wheel.
1st Combination 10 (20-10) 60 (60+0) 30 (40-10)
2nd Combination 11 (20-9) 61 (60+1) 31 (40-9)
3rd Combination 12 (20-8) 62 (60+2) 32 (40-8)
4th Combination 13 (20-7) 63 (60+3) 33 (40-7)
5th Combination 14 (20-6) 64 (60+4) 34 (40-6)
6th Combination 15 (20-5) 65 (60+5) 35 (40-5)
7th Combination 16 (20-4) 66 (60+6) 36 (40-4)
8th Combination 17 (20-3) 67 (60+7) 37 (40-3)
9th Combination 18 (20-2) 68 (60+8) 38 (40-2)
10th Combination 19 (20-1) 69 (60+9) 39 (40-1)
Once again, there are only ten combinations to try. Everything
you need to know to develop these numbers is available from
the combination which is set on the safe (4 times to the left
to 20, 3 times to the right to 60, 2 times to the left to 40)
and what you can diagnose through the dialing procedures
(distance, in dial numbers, of maximum fly travel, and which
wheel contains the problem fly).

Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Troubleshooting/Dialing Diagnostics
You may have noticed that once you determine the starting
number for each affected wheel, it simply becomes a matter of
either adding or subtracting the same digit from the original
combination numbers, beginning with the malfunctioning
wheel. Most technicians feel more confident when they have a
chart to follow. Three different forms are provided in this booklet,
one for each of the situations we have discussed. Feel free to
make copies for your own use.
1st WHEEL FLY STUCK
2nd WHEEL FLY STUCK
3rd WHEEL FLY STUCK
ORIGINAL
2nd NO.
ORIGINAL
3rd NO.
ORIGINAL
1st NO.
–10
–9
–8
–7
–6
–5
–4
–3
–2
–1
ORIGINAL
2nd NO.
ORIGINAL
3rd NO.
ORIGINAL
1st NO.
–10
–9
–8
–7
–6
–5
–4
–3
–2
–1
ORIGINAL
3rd NO.
ORIGINAL
1st NO.
ORIGINAL
2nd NO.
–0
–1
–2
–3
–4
–5
–6
–7
–8
–9
+10
+9
+8
+7
+6
+5
+4
+3
+2
+1
ORIGINAL
1st NO.
ORIGINAL
2nd NO.
ORIGINAL
3rd NO.
–10
–9
–8
–7
–6
–5
–4
–3
–2
–1
–10
–9
–8
–7
–6
–5
–4
–3
–2
–1
+0
+1
+2
+3
+4
+5
+6
+7
+8
+9
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© Copyright 2006, Sargent & Greenleaf, Inc.

16
© Copyright 2006, Sargent & Greenleaf, Inc.
Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Troubleshooting/Dialing Diagnostics
Loose sPLine key
Proper installation of the correct spline key will prevent this
problem from occurring. The proper spline key is one which fits
snugly into the keyway milled into both the drive cam and
spindle. You should not be able to insert and remove it with
your fingers. It should be seated with a small, light hammer
and require side cutters or a spline key removal tool to extract.
A properly seated S&G spline key is oriented with the flag over
and just touching the drive cam. Before 1988, spline keys
were meant to be oriented with the flag crossing over and just
touching the spindle. A spline key is a press-fit part, mean-
ing it is slightly deformed when it is seated. Upon removal, it
should always be discarded and replaced with a new, unused
one. The current spline key number for S&G Group 2 locks is
U17. Stocking and using new spline keys will prevent the prob-
lems we will cover.
The spline key ties the dial/spindle assembly directly to the
drive cam, making these components act as one part. When
the dial is turned any number of degrees, the drive cam
rotates exactly the same number of degrees…as long as the
drive cam stays firmly attached to the drive spindle. If the
connection is sloppy, due to a worn or undersize spline key, a
ten number turn of the dial will likely result in an eight or nine
number turn of the drive cam. In other words, drive cam rota-
tion lags behind the dial by a number or two, just enough to
keep the lock from opening.
Diagnosing a loose spline key can be tricky. A good safe ampli-
fier will help. It will let you hear metal-to-metal contact when
it might be too light to feel through the dial. With the amplifier
in place and adjusted, dial all wheels right to 60. Now turn left
directly to the lock’s contact area (typically between 6 and 14
on S&G Group 2 locks). Slowly oscillate the dial between the
contact points. If you can hear the lever nose striking the sides
of the drive cam gate a half number or more before you can
feel the contact through the dial, you may well have a loose
connection somewhere between the dial and the drive cam,
and the guilty part is usually the spline key.
Our combination is 4 times left to 20, 3 times right to 60, 2
times left to 40. With a loose spline key, dialing left to our first
number (20) would leave the #1 wheel at 18. Dialing right to
60 leaves the #2 wheel at 62, and dialing left to 40 leaves the
#3 wheel at 38. In this case, the two must be added to the
1st and 3rd numbers of the combination, and the two must be
subtracted from the 2nd.
An even easier way to compensate for a loose spline key is to
intentionally “over-dial” the correct combination numbers. No
matter which direction you are dialing, simply pass all the
combination numbers by the same amount. Start over-dialing
by one, and work your way up to five. The lock should open
sometime during this procedure.
stuck Lever
Occasionally, a drop lever will be forced against the lever stop
or will be affected by a bit of debris in the lock case, and it
will not fall into the drive cam gate even after the proper com-
bination is dialed. This is diagnosed by the lack of any contact
points during our dialing diagnostic procedures. Fortunately,
the fix is usually simple.
Dial the correct combination, then move the dial between the
numbers where the contact points should be. We’ll choose 10
for our S&G R6730 (remember, the contact points are about 6
and 14). Tape or hold the dial in this position. Strike the flat
surface of the safe door with a 2 lb. (or heavier) soft-face,
dead blow hammer. A dead blow hammer is filled with lead
shot. It’s designed to impart a greater percentage of the force
of a blow to the safe than an ordinary steel hammer, without
bouncing back. You can substitute a heavy metal hammer if
you use protective material over the safe door (a block of wood,
etc.). One or two blows will usually cause the lever to drop. You
won’t know for sure until you remove the tape and turn the dial
to retract the lock bolt. If the safe door has a handle which
activates the boltwork, tap it lightly in the locking direction.
This action will likely remove pressure from the end of the
combination lock bolt.
CORRECTLY POSITIONED LEVER
LEVER JAMMED AGAINST
LEVER STOP

Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Troubleshooting/Dialing Diagnostics
Broken Lever sPring
Although quite rare, a broken lever spring can produce the
same results as a stuck lever. If the lock is mounted right-
hand, gravity will tend to pull the lever into the wheel and drive
cam gates when they are all lined up properly. A left-hand
mounting configuration orients the lever so gravity works against
a successful safe opening. A non-forced opening requires you
to actually turn the safe upside down. When the weight of the
safe and its environment permit this, it’s a good solution. A
broken lever spring in a vertical-up or vertical-down mounted
lock can sometimes be overcome by dialing so all wheel gates
are under the fence and the drive cam gate is under the lever
nose, then vibrating the safe door with a dead blow hammer.
The dial will have to be moved a few numbers in the direction
which would normally retract the lock bolt after each blow, to
see if the lever has moved in the desired direction. Failing this,
the safe will have to be tipped on one of its sides to accom-
plish a non-forced opening.
The term “handing” can refer to either of two related, yet
distinct aspects of a combination safe lock. One describes
the orientation of the lock after it is attached to the safe
door. The hand of mounting is usually described as right-
hand, left-hand, vertical-up or vertical-down. It is easily
determined by viewing the lock body from the inside surface
of the safe door. If the bolt of the lock points to the right, the
lock is mounted right-hand. If the bolt points left, the lock
is mounted left-hand. A bolt pointing upward indicates a
vertical-up mounted lock, while a downward facing bolt signi-
fies a vertical-down mounted lock.
At one time, it was common to manufacture both right
and left-hand mechanisms. If a lock is mounted left-hand
and its lever fence is located at the top of the lock case,
it is a true left-hand constructed lock. Current production
locks are all, with the exception of some vault locks, true
right-hand mechanisms. Extensive laboratory and field
testing has shown the modern right-hand constructed lock
works equally well when mounted in any of the four common
orientations (RH, LH, VU, VD).
Loose cover screws
If the cover of a lock is loose enough, it can let the relock trig-
ger engage. This is easy to diagnose. After the combination
is entered and the dial is being turned to retract the bold, the
lock will stop about ten numbers before it usually does. For
instance, the 6730 normally stops at about 95 when the bolt is
fully retracted. If the relock trigger is set, it will stop at about
5. If, however, you are working with an unfamiliar lock or one
that has been mis-splined during installation, there is still
an easy method for diagnosing a tripped relock trigger. First,
determine the left contact point of the lock (the number which
comes under the opening index when the lever nose first comes
in contact with the left side of the drive cam gate). Now dial
the combination and turn to retract the combination lock bolt.
The dial will stop before bolt retraction. If the stopping point is
within one or two numbers of the left contact point, something
is preventing the bolt from moving into the lock case. It’s very
likely the relock trigger.
Before you decide to drill, try the following technique: While
exerting very light turning pressure on the dial in the unlocking
direction, firmly rap the door in the vicinity of the lock, using
at least a 2 lb. dead blow hammer (although a metal hammer
and block of wood can be substituted, the dead blow hammer
works best, delivering a much higher percentage of the impact
to the door, rather than bouncing back). Ideally, the shock
will momentarily bounce the lock’s cover up against the case,
resetting the relock trigger for a fraction of a second. If you
maintain light turning pressure on the dial, or try to time your
application of pressure with the hammer blow, the bolt will be
able to move into the case.
LEFT-HAND
VERTICAL-UP
VERTICAL-DOWN
RIGHT-HAND
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© Copyright 2006, Sargent & Greenleaf, Inc.

18
© Copyright 2006, Sargent & Greenleaf, Inc.
Model 6730, 6735, 6738, 6741 Mechanical Combination Lock
Troubleshooting/Dialing Diagnostics
coMBination changing Mistakes
The combination changing process presents a lot of opportuni-
ties for a lockout. Even for an experienced technician, a mental
lapse can cause minor or major headaches. Sargent & Greenleaf
key changeable locks come in two varieties: zero change and
regular change. A zero change lock uses a single index on the
dial ring to open the lock and to change the combination.
It’s impossible to choose the wrong index when setting new
numbers.
The regular change lock has a changing index approximately 8
1/5 numbers to the left of (or counterclockwise from) the opening
index. Presented with two choices, the chance of an error in
combination changing increases dramatically. You should
always check your combinations at least three times before
closing the safe door, so a momentary lapse of concentration
that nudges you into setting a new number on the wrong index
is caught while the error is merely an aggravation, rather than
a catastrophe. Safe owners and end users have been known to
be less cautious, however. It is also a good idea to check your
combination setting prowess by dialing the set numbers 1/2
number lower and 1/2 number higher than what you set. For
instance, if you set a combination of 22 - 67 - 38, you would
dial a trial combination of 21 ½ - 66 ½ - 37 ½. Next, dial a
trial combination of 22 ½ - 67 ½ - 38 ½. The lock should open
both times if you have done a good job of setting the combina-
tion and the lock components are all within spec and working
as they should. Some locks will let you dial as much as a full
number lower and a full number higher than what is set. This
is called "dialing tolerance." Without this tolerance, it would
be extremely difficult to dial open a mechanical lock.
A mistake in combination changing usually means one or more
wheels are 8 1/5 numbers lower than expected. Unfortunately,
we don’t know for sure which wheels are affected. Use the
chart, which follows to work seven combinations. If the problem
is indeed use of the wrong index, one of these possibilities
should work. A fifth of a number is pretty hard to keep track of
when dialing, so we will round the distance between the indices
off to an even eight numbers. Remember to oscillate the dial in
the lock’s contact area after working each combination.
CHANGING INDEX