machining. Burnishing lathes have antifriction bearings
straightedge. For wide flange wheels, no point on back
throughout; an end-drive arrangement; and two
face of rim shall be more than 1/16 inch from
carriages, each holding two opposed rollers with
equalizing screws. Rollers can be fed by handwheel or
by hydraulic cylinders which permit greater pressures.
Hub wall thickness. The thickness of
The average output on a machine of this type is 48
the hubwall in any one wheel measured at any two
axles on an 8-hour shift.
points equidistant from the face of the hub shall not vary
by more than 3/8 inch if the hub is not machined, nor by
18-27. Refinishing Journals on Wheel Pairs
more than 1/8 inch if the hub is machined. Hub length
tolerance is based on finished dimension.
Defective journals on wheel pairs are
regularly turned on axle lathes similar to those
Rotundity. Tread when gaged with a
previously described except for modifications to
ring gage must not have opening between tread and
accommodate and swing the wheel pair. Center- drive
gage at any point over 1/32 inch.
journal lathes (fig 18-6) are modified by providing deep
gaps in the bed for the wheels and a hinged, split
Diameter of bore. The diameter of
center-drive arrangement which can be opened to admit
rough bore shall not vary more than 1/16 inch over, nor
the axle. The carriages are equipped with either single
more than 1/8 inch under the dimensions specified. The
or opposed burnishing rolls. The average output of a
specified rough bore shall be at least 1/4 inch less in
machine of this type using carbide tools is 16 pairs in 8
diameter than the finished bore, subject to 1/16-inch
tolerance and/or 1/8 inch under the diameter specified.
The end-drive axle lathe is furnished with
both headstock and tallstock raised to swing 49 inches
between the rough bore and tread measured in the
over the bed The two carriages are arranged for swivel
plane of the taping line shall not exceed 1/8 inch.
type toolholders, carbide tooling, and opposed
burnishing rolls. Owing to the lathe's design, a simple,
18-26. Machining Axles
shop-built loading arrangement is possible. Production
with 1 man operating the machine will be 20 to 25 wheel
The modern design of the center-drive axle
pairs in 8 hours.
lathe features antifriction bearings in the head- stock,
tallstock, and driver chuck. This lathe is capable of
18-28. Wheel Lathe ,Practice
high-speed operation using carbide tools. An average
production of 10 to 12 axles in 8 hours is possible on
this type of machine.
When a pair of standard one-wear,
Greater production can be secured from
multiple-wear wrought-steel, or multiple-wear cast-steel
end-drive axle lathes if available. One design uses
wheels is removed from service because of a normal
separate drive motors on the headstocks and tailstocks,
service defeat, the wheels may be placed in a lathe and
two carriages with a swivel toolholder and, if desired, an
machined to a new tread and flange contour with minor
expense and little loss of time. This process is then
carriage. Since axles are turned and burnished on one
repeated as occasion demands until the rim is finally
machine and may be rolled into and out of the machine,
reduced to the scrapping limit of 3/4-inch thickness for
machining time is greatly reduced This machine
freight cars and 1-inch thickness for passenger cars.
operated by one man has a production rate as high as
18 axles in 8 hours.
A minimum number of 33-inch
nominal diameter cast steel and wrought-steel wheels
Machining diesel locomotive or streamlined
and 36-inch nominal diameter wrought-steel wheels of
passenger car axles from rough-turned blanks re- quires
various hub diameters should be held in stock. Either
more care than machining freight car axles which
33-inch or 36-inch nominal diameter wrought-steel
normally do not require turning the body of the axle
wheels which have been condemned at 1-inch rim
between the wheel seats. The severity of the service
thickness for use under passenger cars may be
required of these axles necessitates particular attention
reapplied under freight cars for an additional service
to the surface condition of all highly stressed steel parts,
period before they reach the final 3/4-inch rim thickness
and good shop practice is to grind the axles all over
after they have been machined.
The journals of freight car axles must be
rolled or burnished to a fine, smooth finish after