Finishing Trailing Truck Wheels

    With the arrival of the Sherline model 4400 mini-lathe an effort was undertaken to us it to remove the adhered support material and round up the wheel diameter;

    After removal of the wheel from the raft and support, strips of support material remain adhered to the wheels.  During clean up of the locomotive drivers the excess support material was removed using a Dremel tool with a sanding wheel.  Although the sanding process works it requires great care on the part of the operator to avoid over-sanding and creating uneven surfaces.  The mini-lathe can be used to simply turn the part and remove the excess.

     The wheels were chucked up in the lathe three-jaw chuck in preparation to turning off the green support strips.

    The two trailing truck wheels above are shown after turning off the support material on the back using the lathe.

    Since the trailing truck wheels (and locomotive wheels also) were built using a series of short straight edges for the tire, the mini-lathe was used to fabricate a holding tool for the trailing truck wheels so the rim could be turned to a round shape instead of the series of short flats.  The above photo shows a drilling operation into the center of a piece of round Delrin stock being turned into the tool.  The drill is the correct size for a 8-32 tapping operation to be done later.

    After drilling a short section was cut off to make a washer used to clamp the wheel.  The above photo shows a portion of the tool turned down to the correct diameter to fit into the axle hole in the wheels.

    The above photo shows one of the trailing truck wheels mounted on the tool during a fit check. 

    The above photo shows the short flats that formed the wheel rim.  Apparently the Axon software used to convert the 3D CAD design into g-code for the 3D printer transformed the round surface into the series of flats.

    After fit checking the holding tool it was cut-off on the lathe to a length that will keep the wheel close to the chuck on the lathe.

    The above photo shows the overall group of parts that make up a tool mounted wheel to chuck into the lathe when turning the rim.

    The assembled tool above is ready for tightening to clamp the wheel in place.  Once the tool is mounted in the latch the wheels can be mounted and turned one after the other.

     The tool above is now tightened ready for turning in the latch.

     The wheel mounted on the tool is shown chucked up in the lathe ready for turning.

    The turned wheel above is finished turning round.  Note the strings of ABS plastic material removed from the wheel.  The wheel is now round and will roll smoothly on the track.  Should the rounding procedure on the lathe be used in future, the wheels should be made a bit oversize and the lathe then used to turn to final dimension.