< Parts for the Main Frames >
The full size cylinder block is straight
bolted across the main frames. However, for
easier assembly, I prepared a cast iron stretcher
- green one in the CG - between the frames
and the cylinder block. The stretcher also
holds the leading truck.
After facing off the top surface in four-jaw,
the both sides were milled to a desired width.
Next, the spigot for the leading truck was
turned in four-jaw. To find the center, I
glued a small brass sheet on the spigot and
scribed the center on the sheet. Before cutting,
the sheet was removed. Finally, center screw
hole for leading truck pin was opened. The
photo shows the final operation.
The photo shows a view from bottom. Note
the casting is fixed with counter-sink screws,
because the cylinder block will sit astride
the casting and cover the outside faces of
the frames.
These are cast iron brackets for many kinds
of links. Left pair are brake lever brackets,
right top pair are front equalizer brackets,
and right bottom pair are back equalizer
brackets. Regarding brake lever brackets,
I already introduced laser-cut brake lever
brackets, but now I replaced them with cast
iron parts which can hold the brake levers
firmly with slits. As castings, there is
no slit yet. So I have to cut many slits
for them. I started with the front equalizer
brackets.
The illustration shows front section around
the front equalizer brackets. The four squares
(green) show main frames. The brackets (red)
are bolted onto the frames and have inside
and outside slits. The outside slits hold
brake hungers (cyan) while the inside slits
hold equalizer arms (blue).
First I cut bolting faces and steps with
an endmill, and then drilled holes for screws
and pins.
Both inside and outside slits were cut in
a time. Note the chucking strength is dealt
to the root of the slits, so as to avoid
the slack of the chuck.
Small screw holes across the pin bush were
opened. These are for securing the large
pins.
The castings were bolted onto the frames.
Due to a mistake of cast designing, I had
to pack brass plates between the upper frame's
bottom and the casting's top. The brass plates
were fixed with pins onto the casting.
The back equalizer brackets are still more
difficult to chuck. When cutting bolting
faces, I clamped with three bars and removed
one by one. I mean the job was always held
by two bars of the three.
The outside slit is V-shape slit. So the
casting was tilt and cut from both sides.
It is unhappy finish with unstable cutting.
I accept it because the damage is only at
the inside.
They were bolted onto the frames, too. Note
the screws come from inside of the frames,
so as to secure enough clearance for driving
wheels. A boiler barrel holder plate was
fitted right above the equalizer brackets.
The brake lever brackets have only inside
slits. The slits have 'mushroom' shape. First
I cut oval holes from the side, and then
cut square slits from the bottom.
The brackets were bolted on inside faces
of the frames. The photo shows view from
underneath. They were combined each other
with a round bar stretcher.
