Chassis Assembly

    At the front of each of the Front Driver springs a small link connects to the pilot crossbar.  This transfers equalization force to and from the pilot truck to the driver springs.

    Two copies of the pilot crossbar are shown above on the raft and support prior to removal.  Definition was good.  The crossbar combines the forces from Front and Intermediate drivers on each side of the frame to a coupling link which in turn connects to the pilot truck equalization lever. 

    The crossbar equalization link connects to the center of the crossbar and couples to the pilot equalization lever which will be added later after the cylinder assembly is added.  The pilot equalization lever pivots at the center of the cylinder assembly.

    The pilot crossbar equalization link printed with good definition.  Several copies were made in case of problems with yield.  In this case all copies were usable.

    After drilling and tapping all the trapeze levers, intra-chassis levers and chassis, assembly was done using mainly 1-72 screws and a few 3-48 screws for the intra-chassis lever pivots.  Each spring uses 11 leaves.  Also the chassis pedestal binders and chassis were drilled and tapped for 2-56 screws to basically complete all the parts needed to assemble the middle sections of the chassis frame mounting the eight drivers.

    Each spring couples via slots to adjacent trapeze levers except for the rearmost and front-most springs.  Those ends couple to crossbars, one for the pilot truck and another for the trailing truck.  The trailing truck crossbar lever is not yet designed or installed in the above photo.  The trailing truck is coupled via equalization levers to the rear two sets of drivers, Back and Main.

     The front springs of the Front driver couple to the pilot truck crossbar lever.  The Front and Intermediate drivers form an equalization chain with the pilot truck via the crossbar lever.

    The pilot crossbar is installed above linking to the front of each of the Front driver springs and coupling down to a point where the pilot truck equalization lever will be located.

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     The above photo shows a close-up of the pilot crossbar lever and links.  The two small links on the front of the Front driver springs are about 1/2" long and represent about the smallest part that can be made with the BFB-3000.  Yield of those parts was not good, only half of the six parts turned out good.

     The chassis has been assembled with the drivers above showing the location of the various suspension springs and other parts of the equalization system.  These small parts took considerable time to design and fabricate, many taking several attempts to build successfully.

    The chassis with drivers installed begins to look a bit more like a locomotive frame section.  The wheels turn freely and the spring and equalization system seems to work quite well.  The pilot and trailing truck portions of equalization are still to be built and attached.

The chassis center section above has many small moving parts and represents a significant amount of design and fabrication effort.

    Several more parts will need to be fabricated and added to the chassis for the crosshead links and boiler mounts.  Also, the side and other rods will be designed and fabricated to connect the drivers together.