TM 55-203
diameter between the journal and the collar as when
and finishing cuts Sharp-nosed tools and coarse
new.
horizontal feeds must not be used to finish wheel seat
surfaces.
j.
Before use, all unmounted axles must be
c.
Wheel seats must not be polished or filed.
checked in the lathe or between centers for rotundity,
concentricity, and absence of taper of wheel seats and
A smooth machine cut gives the best results. Outside
journals. Where out of tolerance, correction must be
micrometer calipers must be used for measuring axle
made.
wheel seats.
k.
Wheel seats of secondhand axles must be
d.
A taper of 1/32-inch diameter extending a
returned before being remounted All second-hand axles
maximum of 1/2-inch from the dust-guard seat must be
should be magnetic-particle tested before they are
turned in the wheel seat to insure entry into the wheel
remounted. If the journal surface or end of the axle has
and to prevent tearing and gouging during mounting.
any discoloration due to overheating (a light-straw or
Depressions, continuous streaks, or injuries to the
dark-straw color or any departure from the normal bright
surface of the metal of the wheel seat or journals must
finish of the journal) or if circumferential checks or
be removed by a machine cut in a lathe.
cracks are found in the journals, wheel seats, or body of
the axle, the axle must be scrapped unless the
e.
Centering holes in the ends of axles must
discoloration, checks, or cracks can be turned out
taper at an angle of 60 To insure concentricity when
.
without going below the condemning limits.
turning, center holes must be wiped clean before the
axles are placed in the lathe. Any burrs formed around
18-32. Matching Wheels and Axles for Mounting
centers by turning must be removed.
f.
Files should not be used on journal surfaces
Current practice is the use of step sizes in turning
wheel-fit diameters in the axle lathes. The steps are in
or fillets, but they may be used to break the sharp edges
increments of 1/32 of an inch, with the minimum
of the end collars and the dust guard seat Journals must
diameter the shop limit for each particular size of axle.
never be ground with a coarse abrasive, but they may
The step sizes can be numbered from 1 to 13. Size No.
be smoothed with No. 180 grit or finer abrasive cloth
1 is the minimum or shop limit, No. 9 the standard, and
under light pressure.
Nos. 10 to 13 oversizes. The wheels are bored to match
the axles, and a lineup of the axles and size numbers is
g.
Journals should be rolled to a finish with a
listed on a chart for the guidance of each boring-mill
hardened steel roller which preferably has a face 1 1/4
operator. This method of operation requires that only
inches wide and edges which are turned to a 1/8-inch
one nominal size of axle be handled each working day.
radius for the collar end and a radius at the other end to
suit the journal fillet. The roller should be mounted with
18-33. Protective Coating on Journals
a hardened pin and bushing or by roller or ball bearings
in a shank to fit the toolpost.
The journals of all axles on wheel pairs must be coated
h.
While journals are being rolled, they must
with a rust preventive which will not wash away but
which may be wiped off easily.
The journals of
be coated with suitable oil Satisfactory mixtures are 1 or
unmounted axles, if placed in storage, should likewise
2 parts of lard oil and 1 part of lard oil to 3 parts of red
be protected by a suitable coating. It is essential that
machine oil. Before journal surface is rolled, it must be
the coating be applied as soon as possible after the
clean and free from metal chips.
journal has been burnished, since rusting may start
within an hour or so. There are various rust preventives
i.
Journal fillets and end collars must be
on the market which are suitable for this purpose, or a
machined smooth before they are rolled. Dust guard
mixture of paint and oil may be used. The normal
seats should be finished smooth and may be rolled. The
method of application is with a brush. The entire
end collar must be smooth to avoid disturbing the
surface from the wheel hub to the end of the axle must
packing. The horizontal surfaces, when the journal
be covered.
diameter has been reduced 1/4 inch or more, must be
turned and rolled to maintain the same difference in
18-17
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