Busy Making Locomotive Drivers and Axles

    During this past couple of months many attempts to make good drivers and axles were made.  The picture shows a collection of black PLA, Green ABS and one white ABS wheel, seventeen drivers in all.  Also shown are five axles on the table plus two more inside the assembled driver sets at the top.  Each driver takes about 3hr 30m to build and axles take a bit longer, so the BFB-3000 3D printer has been steadily in use.
    The main difficulties have been getting good definition of the wheel flange and good finish and detail on the wheel surface.  Attempts included using various combinations of raft and wheel material.  The best overall results are obtained using PLA raft and supports with ABS wheel material.  Conversely, for the axles, the best results are obtained using ABS raft and supports with PLA axle material.  All parts required post build clean-up to remove raft and support material and small strings of build material.
    The next step will be to glue together examples to determine the best method of permanent assembly.  BFB indicated that super glue is a good candidate for bonding.  At the top of the photo on the left side is a gluing fixture fabricated to space the wheels accurately and hold them squarely aligned during the gluing process.  That assembly with rubber bands consists of two half shells of a round spacing tool held with blue rubber bands, two wheels and an axle held with tan rubber bands.  Not visible are two bearings that are inside the clam-shell spacer on the axle.  At the right on top is an assembled wheel-axle pair with bearings on the axle shaft.  The bearings of course are free to rotate on the axle.  The bearings will interface with slots on the locomotive frame to provide a way for the wheels to slide up and down for operation of the equalization system and freely rotate as the locomotive moves on the rails.
    Glue procedures will be worked out using some of the wheels and axles shown above, but none of these will be used in the final model locomotive.  Black ABS material has been ordered from BFB to manufacture the final model wheels.  Black PLA is already on hand for the axles and bearings.