Kozo K-27 Valve Gear
This construction segment will
concentrate on the valve gear for the locomotive. A photo of
K-27 463 is provided for reference.
This is one of the valve stem
crossheads that slides in the valve crosshead guide immediately behind
the valve cylinder. The combination lever, vertical lever behind the
cylinders in the photo above, will pivot on a shaft that will be added
between the two holes. The valve stem will screw into the back end of
the part. December 31, 2021.
The valve stem crossheads have been
completed along with the stainless steel valve stems. These are shown
assembled in the valve crosshead guides. The valve body will be mounted
to the top end of the stems. January 29, 2022.
This is the start of a radius rod with two slots and a hole cut at one end of the 3/8" thick stock. The other end
has been profiled down to about 1/8". The next step will be to cut off
the lower section that was used to hold the piece in the milling vise
during initial machining. The thin portion will then be tapered down
and each end will be treated to a radius. February 5, 2022.
Machining of the radius rods has been
completed. They had to be cut to width, a radius added to both ends and
a taper cut from the big end to the small end. April 17. 2022.
The heavy machining of one of the
combination levers has been completed. The bottom portion used for
holding the part in the vise will be cut off. One end will need to have
a radius cut and taper cut will also be made to the thin section. May
The machining of the two combination levers has been completed. May 29, 2022.
This is the start of a pair of eccentric cranks that mount on the main crank pin and drive the valve gear. June 26, 2022.
The completed set of eccentric cranks which are mirror images of one another. July 4, 2022.
A completed set of crosshead links made out of 1/8" thick stock and machined as a matched set. July 9, 2022.
This is the start of one of the
eccentric rods. This is about as far as it can go at this point since
the other end will need to be drilled with a jig after the valve
position has been determined on the engine. July 24, 2022.
The center sections of the link
assemblies have been milled to the basic shape as a pair on a fixture.
the link block will slide up and down in the slot as the Johnson Bar is
adjusted. Further machining will be required after they are bolted to
the outer shells of the link assembly. July 31, 2022.
This is the start of a matched set of
outer link pieces. A center section from the prior photo above will be
sandwiched between two of these. August 14, 2022.
These are the roughed out pieces that will make up the body of one link assembly. August 20, 2022.
The two link bodies have been cut to
the final shape and assembled. A radius rod has been inserted to give
some perspective. The link bodies will still need the pivot
points/trunnions soldered in the hole at the center and a phosphor
bronze link block will be machined to provide the bearing for the
radius rod. August 21, 2022.
The phosphor bronze link blocks that
slide up and down in the slot of the link assembly have been completed.
These are complicated little parts since the sides must have the same
arc as the slot. The next step is to file the ends of the slots square
so that the link blocks can go all the way to the top and bottom.
August 28, 2022.
A set of trunnions have been machined
to provide the pivot points for the link assembly. These will need to
be soldered to the outer shells. September 11, 2022.
The bushings for the large end of the eccentric rods made from phosphor bronze stock. September 25, 2022.
The trunnions have been silver soldered to the out link shells to provide the pivot points. October 1, 2022.
These two pins will attach the link blocks to the radius rods. October 1, 2022.
More pins for the valve gear. October 23, 2022
The remainder of the pins for the valve gear. October 30, 2022.
The valve set with each being about 3/4" diameter and about 1.5" long. November 6, 2022.
The ends of the slots in the link
centers have been filed square to allow the link block to travel from
end to end. A few photos above you can see how the slot ends were still
shaped like the cutter used to mill the slots. November 20, 2022.
The valves have been secured to the
valve stems and a slot cut on one end which will allow a screw driver
to be used to screw the stem into the crossheads. November 27, 2022.
This is a setting gauge that will be
used to position the eccentric cranks relative to the cranks on the 3rd
driver. November 27, 2022.
The eccentric crank setting gauge in
action. The crank on the driver is at rear dead center and the pin
through the eccentric crank is lined up with the hole in the gauge. The
eccentric crank screw is then tightened to secure the eccentric to the
crank pin and then a small pin hole is drilled through the crank and
crank pin to further secure it. November 27, 2022.
The right eccentric rod has been
completed and the bushing fit to the large end. These take more time
since the distance between the pins must be determined according to the
as built rod assembly. An adjustable drilling jig is used to find the
correct length and then the jig is used to drill the large hole.
December 4, 2022.
Both of the eccentric rods have been completed and the valve gear can now be assembled on the locomotive. December 11, 2022.
The valve gear fitted to the rest of
the assembly. This took segment took me quite a bit of time to
complete. The next segment should go quicker with the building of the
axle pump. December 11, 2022.
Another view of the valve assembly.