Kozo K27 Cylinders



This is the start of the second part of the cylinder assembly construction. The holes have been drilled and tapped for the cylinder and steam chest covers as seen on the left. The right shot shows the two sight holes at the top, the snifter valve and lube holes in the middle and the steam inlet hole from the prior section at the bottom. Next will be the drilling of the exhaust passages which will require an interesting setup on the milling table. January 3, 2020.


Today was spent drilling the exhaust passages that run from the outside grove of the steam chest to the center of the backplate. This involved mounting the assembly rotated 36 degrees on a 90 degree angle plate to orient the piece for drilling. One of the more complicated steps in the machining of the cylinders. January 4, 2020.


Here is the view of the exhaust passage from the backplate side of the assembly. There is a second exhaust passage heading out to the other end of the steam chest. These passages will run through a T-pipe between the frame rails and then up through the bottom of the smoke box to exit at the stack. Next up will be another set of passages that will require a slightly easier setup for machining. January 4, 2020.


The project today was cutting various angles on the end plates. This will assist with drilling the steam passages between the steam chest and the cylinder and also brings the end plates closer to the final shape. The steam inlet, snifter valve hole and lube holes are visible at the top. The drain hole for the cylinder drain cock can be seen at the bottom. January 5, 2020.


The operation today was to drill the steam passages between the cylinder and the steam chest. This was performed with the cylinder assembly rotated 37 degrees on while mounted on a 90 degree angle plate. One assembly has been completed and the second still needs to be drilled. January 12, 2020.


The steam passages have been drilled at the ends of both cylinders. A rotary tool was used to round all of the edges inside the cylinders to prevent the O-rings from being cut as they are installed. January 20, 2020.


One of the end plates has been rounded and angles cut to the final profile. Only three more end plates to trim up. January 20, 2020.


Both assemblies now have the end plates finished to the final shape. Next I'll be working on the caps for the steam chests. February 8, 2020.


The front heads for the steam chests have been completed and the front outer covers are also done. February 15, 2020.


The outer covers for the back of the steam chests are completed. Work has started on the steam chest back heads which are fairly complicated due to having the support for some of the valve gear. February 16, 2020.


The lathe work for one of the steam chest rear heads has been completed and milling has been started. Another flat will need to be cut on the bottom side and then some angle cuts to taper from the large end to the flats. Then there will be some hole drilling for the mounting holes and covers. February 17, 2020.


One of the front steam chest heads has had most of the major milling with both flats and angle cuts. A small triangle will be cut in the angled portion and then the bolt holes will need to be drilled. March 15, 2020.


The pair of steam chest rear heads have been machined and drilled. The front one is shown without the decorative outer cover and the rear one has it set in place. There is one more machining step that will cut a small triangle in the sides near the cylinder assembly. March 21, 2020.


The steam chest rear heads have been completed with the machining of the triangle openings in the sides. March 22, 2020.


The two cylinder heads have been completed and test fit on the assembly. This is the front side and the center holes are for mounting the covers. March 29, 2020.


The two decorative covers for the fronts of the cylinders are complete and test fit along with the steam chest covers. March 29, 2020.


The lathe work for the rear cylinder heads has been completed. April 4, 2020.


The cylinder heads have been drilled and test fit on the assembly. The next step will be to machine the cross head guide bracket that will be silver soldered to the top side of the cylinder heads. April 4, 2020.


The supports have been silver soldered onto each of the rear cylinder heads and will need to be shaped while mounted on the cylinder assemblies. April 11, 2020.


A plate has been bolted onto the back of the assembly to allow for accurate measurement of the cut that will be made on the support. A pin will also bee inserted into the cylinder rod opening for the vertical measurement. April 11, 2020.


The blocks on the supports have been squared up and the mounting hole drilled. Final machining of the angled sides has also been completed to finish the parts. April 11, 2020.


The lathe work on one of the steam chest liners has been completed. The next step is to mill the steam passage slots within the grooves every 90 degrees. April 18, 2020.


Cutting of the steam passage slots in the steam chest liners has started. Only 15 more to go in the front piece and 20 in the rear piece. April 19, 2020.


The five slots every 90 degrees have been machined into the steam chest liners completing these parts. April 22, 2020.


The four plugs for the sight holes in the side of the valve cylinders have been completed. The plans had hex head but I chose square head like the prototype. Next will be the snifter valves that mount in the center hole in this view. April 25, 2020.


The two snifter valves have been completed with one in place and the second next to it showing the captive ball in the bottom that seals under steam pressure. These valves were made to resemble those found on 463 as opposed to a simple hex fitting with the vent hole in the top from the plans. May 3, 2020.


The decorative bolts for the cylinder covers in various stages in the machining process. The treaded end is extra long to allow holding in ER-40 collets while the hex head is cut and the end rounded. May 3, 2020.


The decorative bolts for the front covers have been completed and are shown here on the cylinder assemblies.. May 9, 2020.


The phosphor bronze bushings for the valve shafts and the piston shaft have been completed. May 11, 2020.


This is the main portion of the T-pipe that will direct the exhaust from the cylinders to the smoke box. The next step is to silver solder the T into the large hole. May 16, 2020.


The T-pipe after soldering the center piece and drilling the cylinder mounting holes. The center opening still needs to be tapped but I don't have anything larger than 1/2"! May 17, 2020.


This piece will bolt on to the bottom of the T-pipe above and perform two functions. The bottom portion provides the pivot point for the lead truck equalizer. The top portion deflects the exhaust from each of the cylinders upwards into the smoke box. May 23, 2020.


Today the top of the T-pipe was threaded and the whole assembly was test fitted to the frame. The equalizer lever for the lead truck can be see pinned at the bottom center of the T-pipe. The next step to close out this section of the build is to fabricate the cylinder assembly jackets to give it a finished look. May 24, 2020.


The first cylinder jacket has been formed and all of the mounting holes drilled and tapped in the cylinder assembly. It will still require cutting openings for the various items that stick out and there is the frame for the hydrostatic lubricator inspection hole in the center. May 24, 2020.


The openings in the first cylinder jacket have been completed. Two on the bottom for the drain cocks, two on the side for the sight hole plugs, two on the top for snifter and oil port and one at top back for the steam inlet. May 29, 2020.