TM 9-1829A, April 1944
18/100
2021-07-07
Figure 19: Removing second gear from frame
k.
Remove oil wick:
Remove sealing plug and oil wick from neck of speedometer frame. Small screwdriver or
scratch awl may be used.
l.
Remove magnet and first gear
(fig. 20).
(1)
From “L” Speedometer: Back off screw in tool (T-170654): Then assemble tool on threaded neck of
main frame. Turn screw down until it has forced magnet shaft out of collar. Remove tool, collar, collar
thrust washer, magnet and shaft, and thrust washer.
(2)
From “N” series speedometer: Back off screw in tool (T-170654). Then assemble tool on threaded neck
of main frame. Turn small screw down until it has forced magnet shaft out of the collar. Remove tool,
collar, and thrust washer. Push magnet and shaft back to its original position. Continue to hold magnet
and shaft in its original position and smooth down the ragged flare edge with a safety-edge file.
Caution:
Do not force magnet shaft through frame bearing. Flare must be filed until magnet shaft will drop out of
frame, otherwise frame bearing will be scratched beyond repair. Do not touch end of frame with file as
this is a thrust bearing surface.
m.
Remove intermediate gear
(perform this operation only if gear is stripped or otherwise damaged): Remove
intermediate gear from main frame by drilling to remove riveted portion of stud. Drive stud out of frame with
small punch.
Figure 20: Removing magnet shaft collar, using dismantling wrench (T-170654)
7. Cleaning, inspection, and repair of parts.
a.
Cleaning of unit parts:
Clean all internal parts in dry-cleaning solvent. In many cases only a complete
cleaning will show up the parts which have been causing trouble. The cleaned parts should be dried with
compressed air. Use care in drying the speed cup so the hair spring is not damaged. Make sure speed cup
bearing in magnet and magnet surfaces under compensator are fully dry, because wet cleaning fluid at these
points will cause corrosion due to thinned out watch oil.
b.
Inspection of unit parts:
Inspection of individual speedometer parts is a matter of close observation,
frequently under a magnifying glass, and a sense of feel for rough bearing points. Following are suggestions
for inspection of various parts: