Machining I - RH Journal Box
Nelson Riedel Nelson@NelsonsLocomoitive.com
Initial: 2/28/03 Last Revised: 06/05/2004
I mentioned elsewhere that my limited machining
skills are self taught. This leads me to frequently do things
the hard way. Often I use a cumbersome technique that I'm pretty
sure I can do rather than trying a new way. This reminds me of a
comment by a friend after I was critical of people using a much less than
optimal software tool because they understood that tool. My friend
observed that if your only tool is a hammer, most your tasks begin to look
like nails. Please view my techniques from this perspective.
truck castings consisted of two pedestals, four journal boxes and four
wheels. Rather that describe how I machined each type of
casting, I decided to
discuss the RH Journal Boxes and the Wheels in detail and skip the rest.
This note deals with the Journal Boxes. The wheels are discussed in
a separate note.
|Journal Box Castings: The RH Journal Box
casting is shown on the right. This is exactly as I received
the casting from Kenneth except that the sprue has been sawed
off. (The dark rectangle on the top is where the sprue was
The three photos below show the finished Journal
Box. The left photo is a rear view and shows the axel
bearing installed and retained by an internal retaining
ring. The middle photo shows the front of the Journal
Box; the rectangular recess will contain a bronze line shaft
bearing. The right photo shows the front with the
cover that retains the line shaft bearing in place.
.So how did I get from the rough casting to the finished
casting? Well, I following the instructions in the drawing below. This is one of the 85 drawings that Kenneth makes available
to show how the castings should be machined. I bought the drawing
set that also includes three pages of photos before I bought the
castings. This enabled me to judge whether I could actually do the
machining before I laid out the big bucks. The drawing
is presented here with Kenneth's permission.
first thing I did was to examine the rough casting and the drawing and try
to visualize where material had to be removed from the
casting. In spite of fooling around with it for at least 30
minutes spread over a couple days, I didn't notice the curved recesses in
the top until I was ready to mount the castings to the side frames.
These recesses are clearly shown in the view in the upper left corner of
the drawing. Fortunately, I didn't overlook anything that
caused me to remove material where I shouldn't have.
||The first thing I did to the Journal Boxes was
to take a very fine cut on the bottom as shown on the left and a
very fine cut to the top as shown on the right. The rough cast
front and back surfaces were used as the
reference. These fine cuts provided smooth
reference surfaces for future measurements. These
cuts were made on all 6 Journal Boxes before moving on to the next
||The next thing was to take a light cut on the front
face as suggested in the drawing above. This is shown on
the left. I used a fly cutter. This cut was made
on all six Journal boxes.
The cut was then taken on the back to achieve the 1.56" dimension.
Once the correct cutter height was set on the first box it was very
easy to do the other five boxes.
|At this point the top, bottom, front and back of
each box was smooth. The overall height was still too large
and would be adjusted later. Each box was examined to
determine the center of the square boss and relate it to the
height of the centerline through the bearing. It was found
that the bearing center line could be in the middle of the square
boss and material could be removed later from the base to achieve the
correct bearing centerline height. A hole was then drilled
through the center square boss of each Journal Box. This
hole was the same size as a large center
drill. The center drill was then inserted in the hole and
used to align the box in the four-jaw lathe chuck such that the
hole was on the lathe center as shown on the right.
The hole through the box was then enlarged with a 5/8"
drill (Silver & Deming) as shown on the left below. The
hole was then bored to the correct stepped diameter as shown in the
center photo below. The bearing was tested for a loose fit
in the larger diameter hole. The last step was to cut the
groove for internal retaining ring using a boring bar with a very
narrow tool bit as shown on the right below. All
these operations were completed on each box before it was removed
from the chuck.
||The bottom of each each Box was then trimmed
as required to achieve the correct bearing centerline height as
shown on the left. Note how the angle fixture is used to insure
that the base is perpendicular to the front. Once
all the bases were correct the top of each box was trimmed as
necessary to achieve the correct height as shown on the right.
||The next step was to machine the front surface. The left photo shows machining
the recess for the cover plate. The right photo
show milling out the deep recess for the line shaft bearing.
||The next problem was to determine the locations of the
mounting holes in the top and bottom. These holes are
centered on the bearing centerline. To accomplish this a
dummy axel was turned and mounted to an angle plate as shown on
the left. The location of this axel in relation to one of the
vertical edges of the angle was then measured. Each box
was then slid onto the dummy axel and the position of the axel
used to mark off the correct location of the mounting
|The photo on the above right shows a box in position to
mark the base. Once all six bases were marked, the dummy
axel was repositioned and the mounting holes in the six tops
marked off. The drilling of the mounting holes was
deferred until the Journal Boxes were test positioned in the side
As mentioned previously, when fitting the Journal Boxes to the
side frames I discovered
that one more machining operation was required on the top. The photo on the right shows this
Cover Plates: When I started to write this note I discover
that I didn't have photos dealing with the cover plates for the RH Journal
Boxes but did have some for the LH Journal Boxes so decided to use
them. The same technique was used on both sides.
always had trouble making square plates with straight edges.
The technique that works for me is to saw the plates a little oversize and
square them up in the mill as shown in the left photo below. I next
very carefully marked off and drilled the holes in one of the
plates. This plate was then used as a pattern to drill the holes in
the other five plates. Each plate was then used as a
pattern to drill the holes in the Journal Boxes. I carefully positioned
a plate on a journal box and drilled one hole as shown in right photo
below. I then tapped that hole and used a screw to
secure the plate. Once secured, the plate was used as a pattern to
drill the other five holes.
This wraps up the Journal Boxes. The machining of
the wheels are discussed in the next note.