Kozo K-27 Rods
Before I get too far with
the rods, I
need to quarter all of the drivers. This is the start of a jig to
perform the quartering. I didn't get too far on this today as the metal
shop took forever cutting of a length of stock for the rods. December
A V-notched plate will be
each end of the jig to set the 90 degree angle. A clamp will be added
to the center plate to strap the axle into position. December 31, 2020.
The V notched end plates have been added which will allow the cranks to
be set 90 degrees apart from one another. A pin will be slipped into
the left crank and be clamped down to the block at the front left side
of the jig. A pin can then be slipped into the right crank and brought
up against the V block to set at 90 degrees. The cranks are initially
locked into position with Loctite retaining compound. Once dry a pin
hole will be drilled through the back flange of the crank and through
the axle to insert a locking pin. January 1, 2021.
The jig has been
completed with the
two brass straps to hold the driver set into position. The left crank
has already been pinned and is strapped to the jig to keep it up
against the stop. Retaining compound has been spread on the right end
of the axle and the crank has been adjusted so that the pin through it
is advanced to the 90 degree stop. The assembly will be left in the jig
while the retaining compound sets and then a 1/8" pin hole will be
drilled through the crank flange and axle to pin it in place. The
remaining three driver sets will receive the same treatment. January 3,
This is about as far as I
able to get on the main rods since I am waiting on a special bit for
fluting them that must be on a slow boat from China. These things are
pretty hefty with a width of just over 3/4" x 10 1/4" long and 5/16"
thick. They will have bushings added at both pin locations. January 9,
Work is progressing on
intermediate side rods that will run between drivers 2 and 3. These are
about 5 1/4" long and 1" wide at the main crank hole. The lower piece
has been heavily machined as compared to the blank at the top. A slot
will be cut in the small end for the knuckle joint and then there will
to be some radius cuts to finish up both ends. January 10, 2021.
The second intermediate
side rod has
been machined and a slit cut in the knuckle joint of each rod. This is
the stopping point until all of the rods have been completely drilled
to match the crank pin spacing. Each rod will then finish shaped with
various radius cuts to match the prototype (they still look a bit
blocky). January 18, 2021.
The special corner radius key cutter
bit finally arrived so I worked on the fluting of the main rods. This
requires three different cuts with one straight between the centers of
the two holes. The second and third cuts require that the large hole
end be dropped down in the vise to angle them away from the center. The
small hole end is left at the same height for all of the cuts by
pivoting around a rod through the hole. The backsides of the rods will
require the same cuts to make them symmetrical. January 24, 2021.
With the fluting work completed
attention now turns to shaping the rod. This one has been tapered from
the big end down to the small end. Next the small end will get a radius
that will taper down to meet with the narrower fluted portion. January
Both of the main rods have been
tapered from the big end down to the small end. The thickness of the I
beam portion of the lower rod has been reduced to the final size. The
upper rod will need to be thinned and then both rods will be rounded at
the small end. February 7, 2021.
One of the main rods has been finished
to the final shape. This required a number of cuts on the small end for
the radius on the end, the taper and the fillets at the transition from
the small part of the rod to the end block. The other rod will receive
the same treatment and then there will be some appearance bolts and an
oil cup added to the big end. May 16, 2021.
Both of the main rods have now been
machined to the final shape. Oil cups have also been machined and added
to the big end of the rods. There is still bolt and nut detail to add
to the big end and bushings at each end. May 23, 2021.
The front side-rods are a work in
progress with each starting from a 3/8" x 1" x 6" piece of steel. Each
end is offset from one another so there is a heavy side cut started on
the upper rod. The bottom rod still needs quite a bit of machining. May
The front side-rods are mirror images
of one another so this view provides a look at both sides. This is
about as far as the machining can go until all of the rods are fitted
on the engine with final holes drilled for the crank pin of driver 1
and the hole in the tab for the intermediate side-rod. May 31, 2021.
This the start of the rear side-rods that will have a knuckle joint at
one end and a bushing for the driver 4 cranks. The top one will require
some milling on each side for the offset and then the grove for the
knuckle joint. June 5, 2021.
This shot provides a view of how the rod set will connect once
completed. Final drilling for the joints and the front driver crank pin
will be completed with a set of drilling jigs. Once fitted to the
engine the final profile of each of the rods will be completed. June 5,