TM 9-1829A, April 1944
32/100
2021-07-07
turning stock out excessively. Best results are obtained by placing pliers so that side of nose lies flat against
magnet plate. Lift off field plate and speed cup.
i.
Remove second gear
(fig. 41). Insert the lower bearing part of gear extracting tool (ST-263-34) in third gear
bearing so that teeth of extracting tool mesh with second gear. Press tool against gear so that it will mesh
deeply and turn tool clockwise, which will force second gear outer bearing from frame. Remove second gear,
being careful not to lose any thrust washers which may be on gear shaft or stuck against inner bearing.
j.
Remove magnet:
Check side play of magnet shaft. This must not exceed 0.003 inch. If side play is within
limits, and magnet and shaft are in good condition, it will not be necessary to remove shaft. If it is necessary
to remove shaft, screw tool (T-170654) on frame and tighten plunger against end of shaft (fig. 42). Remove
collar, file burs from shaft and take magnet from frame. Do not drive magnet shaft through main frame bearing
until all burs are filed smooth, so that shaft will pass through bearing freely without damaging it. Be careful
not to lose thrust washers on either end of magnet shaft.
k.
Remove intermediate gears
(SPL-type): Do not remove intermediate gears from frame unless gears are
worn, damaged, cracked or distorted. If these conditions are found, file or grind off staked portion of shaft on
outside of main frame, and drive stud out of frame with hammer and punch.
17. Cleaning, inspection, and repair of parts
a.
The procedure for cleaning, inspection, and repair is the same as for the SPA series. Refer to paragraph 12.
18. Assembly
a.
Install magnet:
Place thrust washer on magnet shaft with tang toward main frame, so it will engage with one
frame web to prevent it from turning. Insert magnet shaft in main frame, and place thrust washer and collar
on end of shaft. Press collar into place with tool (fig. 31). Inspect shaft to make sure there is enough metal
for proper flaring, then flare with special tool (fig. 32). When new magnet shaft is used, it may be necessary
to use more than one thrust washer under collar. After flaring, measure magnet shaft end play with 0.002 inch
feeler gage all around the entire magnet shaft to make sure it is not loose and there are no tight spots. Tighten
with additional flaring if loose. If there is not enough clearance loosen with special tool (fig. 29).
b.
Install second gear:
Grease both bearing surfaces and teeth with No. 00 grease, O.D. Place thrust washer on
inner end of shaft and insert gear in main frame. Place outer bushing on shaft of gear with beveled side in and
press second gear and bushing into frame. Adjust end play to 0.005 to 0.010 inch by installing thrust washers
on shaft, then with tool (ST-263-35) stake edge of main frame against bushing at three places, equally spaced
around bushing (fig. 43).
c.
Install speed cup:
Thoroughly clean lower staff jewel. Place one drop only of watch and clock oil on end of
speed cup staff. Place speed cup over magnet, making sure lower end of staff enters jewel in top of magnet
shaft.
d.
Install field plate:
Place field plate over speed cup, line up field plate and magnet, and clinch edges of plate
with pliers. Make sure the assembly runs true after it has been assembled and that the field plate is tightly in
place.
e.
Install third gear:
Grease lower bearing, place washer on lower end of shaft and insert in bearing.
f.
Assemble front jewel bracket
(figs. 33 and 39): Screw jewel not more than three-quarters way into bracket.
Place hair spring regulator over top of jewel with anchor end toward third gear bearing hole. Install jewel
lock nut with shoulder face downward, being careful to enter shoulder into hair spring regulator. At this time
clean jewel and end of speed cup staff.
g.
Install front jewel bracket
(fig. 39):
(1)
Install jewel bracket in its place on main frame, being sure to line up centering pins with holes in bracket,
and at the same time guide third gear into its bearing. Install two holding screws, then make sure there is
0.005 to 0.010 inch play in third gear. Install third gear tension plate. Caution: While tightening bracket
screws make sure there is at no time a tightening down of the jewel against the speed cup staff (this
condition will not exist if the jewel has been turned down three-quarters way or less as instructed in
subparagraph f above).
(2)
End play in speed cup staff must be 0.003 inch, which is obtained by adjusting the total end play in speed
cup and magnet shafts to 0.005 inch. Place a 0.005 inch feeler gage (ST-263-27) between front jewel and
shoulder on speed cup staff (fig. 34). Hold lock nut with wrench and screw jewel down with special
screwdriver (T-178705) until it comes lightly to rest on feeler gage. Tighten lock nut in this position.
Recheck end play with 0.005 inch feeler gage to make sure this adjustment has not changed when
tightening lock nut.
(3)
A check of both bracket jewel adjustment and magnet shaft adjustment should be made at this time as
follows: Holding speedometer in one hand, with thumb pushing up against bottom of magnet shaft, taking