AT&T Bell System Plant Series Adjustment Procedure page 2

SECTION 032-709-701
the plunger or by rotating the plunger
to remove backlash when the key is in
either its operated or unoperated position.
Gauge by feel.
* 2.03 Contact Alignment: Fig. l(A) - The
contacts shall line up so that the
point of contact falls wholly within the
boundary of the opposing contact at a·11
times during contact.
Gauge by eye.
(A)~~
Fig. l - Contact Alignment
*
2.04 Spring Clearance
(a) Fig. 2(B) - There shall be a clearance
between springs designed never to make
contact and between any spring and the
frame whether in the operated or unoperated
position of the key of:
Min 0.016 in.
Gauge by eye.
(b) Fig. 3(A) - The distance between
springs designed to make contact shall
be:
Min 0.008 in.
except at the contact points.
Gauge by eye.
*
2.05 Contact Separation: Fig. 2(C)
(a) Unless otherwise specified, the sepa-
ration between any pair of contacts
normally open or between any pair of con-
tacts that are opened when the key is
operated, shall be:
Min 0.016 in.
Gauge by eye.
(1) The separation of the outside con-
tacts can be gauged visually with-
out removing the spring unit from the
keyshell, but in order to view the sepa-
ration for inner contacts of any key it
is necessary to remove the spring as-
sembly from the shell and also the
plunger. Holding the spring assembly
at the base, place the plunger between
Page 2
the plunger springs in such a position
that the center of the plunger will be
approximately in line with the center
of the base as shown in Fig. 3. This
will approximate the actual condition
when the key is assembled. Turn the
plunger to its operated position and
note whether or not the specified con-
tact separation requirement is met.
PLUNGER RETAINING l'>CREW ~
INNER .CONTACT SPRING
INSULATOR
SPRING ASSEMBLY
MOUNTING SCREWS
SPRING ASSEMBLY SCREW---.!
(0)
Fig. 2 -Spring Clearance, Contact Sepa-
ration, and Contact Pressure
(b) Nos. 272F and 272G Keys: The sepa-
ration between any pair of contacts
normally open or between any pair of con-
tacts that is opened when the key is
operated. shall be:
Min 0.025 in.
Gauge by eye. See (a)(l}
(c) No. 406J and 538-type
Key~
- Make-break
Spring Combination: The separation
between the normally open contacts or the
contacts that are opened when the key is
operated, shall be:
Min 0.012 in.
Gauge by eye. See (a)(l).
*2.06 Contact Pressure: Fig. 2(D)
(a) Unless otherwise specified, there shall
be a pressure between all closed con-
tacts of:
Test - Min 50 grams
Readjust - Min
55
grams
Use the No. 68B gauge.