Up one level Neidrauer Adventures Photo Album and Blog » Building a Live Steam Locomotive - the Mikado Project » Section 7 - Trailing Truck
Section 7 - Trailing Truck
Completed! The Delta Trailing Truck. May 2005 - Aug 2007

The delta trailing truck frame in cast iron. It has already been machined. 5-May-05 The next assembly to start will be the trailing truck. We start with the equalizing arms. 10-May-06 Here is a familiar process: rough boring the trailing truck axle boxes, after completing a truing cut on the face. 10-May-06 Checking the bore to match the bearings size. 10-May-06 Another familiar operation: turning a mandrel to mount on the angle plate to machine the axle boxes. 10-May-06 Milling the axle box openings using the same fixture techniques used on the main axle boxes. 17-May-06 Facing the front of the trailing truck axle box. A few tapped holes to mount the decorative box cover and we are done. 14-Jun-06 Now we get our chance to machine fresh cast iron wheels for the trailing truck. The four-jaw chuck is used. We machine the back first, then rough bore the hub. Turning it around, we indicate the hub back to center and rough turn the face closer to the finished thickness. 14-Jun-06 Turning the trailing truck wheels. The outer diameter has been rough turned, along with the hub and tire thickness. We add the decorative relief to simulate a shrunk-fit steel tire on a spoked hub like the prints call for. I'm happy to say the cast iron is good quality with no voids or hard spots. It's just 14-Jun-06 The two trailing truck wheels rough turned. We will finish turn the tread profile and finished thickness dimensions after they have been pressed on the axle. 14-Jun-06 Facing the end of the trailing truck axle. 14-Jun-06 Using the height gage on the granite block to get the correct length since the 9 28-Jun-06 Turning the trailing truck axle between centers. Same process as we used for the main axles. 28-Jun-06 Lacking a micrometer carriage stop, we use an adjustable parallel set to the correct offset. The parallel was set using a micrometer. 5-Jul-06 Making a fixture to hold the trailing truck Rockers for turning. We did not want to disturb the setup in the big Bridgeport, so the little mill/drill was put into service drilling and tapping the holes. 11-Jul-06 The arbor for turning the trailing truck rockers mounted in the six-jaw chuck. The chuck jaws are on the round portion of the mandrel. The quarter inch square stock is bolted onto the mandrel to drive the rockers, like a dog is used during turning operations. Bill pointed out I bolted it on up-side down, the notch in the stock is supposed to provide clearance against the casting. 11-Jul-06 The rocker casting on the mandrel ready for turning. 11-Jul-06 The finished trailing truck rocker. Looks good! 12-Jul-06 Preparing to turn the finished tread profile on the trailing trucks. Earlier that weekend I used the hydraulic press at Joel's shop and pressed the wheels onto the axle. Turning the 10 degree flange taper on the trailing truck wheels. 12-July-06 12-July-06 Turning the tread profile in the trailing truck wheels. This challenged machinist and machine, since this light-duty lathe is not really rigid enough to turn an 1/8 6-Dec-06 After leaving this section incomplete back in July while waiting for replacement brass parts to come in (I didn't want the aluminum parts originally purchased), we came back to it tonight. After machining the bottom and sides, we are milling pockets into the rocker guides so the screw heads wil be flush with the top of the guide. 6-Dec-06 While Bill was machining the rocker guides, I worked the slots in the rockers (labeled 6-Dec-06 Another part to bolt on! That always feels good. The rocker guide (top) has been bolted to the tail cradle, the rocker positioned in the guide and the rocker base (unmachined) placed in the trailing truck frame to check alignment. Bit of a problem, the base does not line up with the rocker. The truck frame came out of the foundry wider than called for by print, so we will have to make some adjustments.... 6-Dec-06 Machining the slot in the Rocker Bases. 6-Dec-06 The completed Rocker assembly. 30-Jan-07 After assembly, we find we have machine the pockets since the casting is slightly larger than the print, 30-Jan-07 Using round-nose bit to enlarge one side of the rocker pockets. 30-Jan-07 Milling the rocker pad pockets out so the rockers will line up and have enough freedom of motion as required by print. The raw casting is a little bit wide of print. 30-Jan-07 Test fitting the trailing truck. More clearance is needed. The truck looks good. 7-Feb-07. I've purchased some cup washers to use instead of the casing boss, so we machine the boss down and put a pocket in it for the washer. 14-Feb-07 Try #2 to widen the rocker pockets. Here we use a 5 degree taper mill that my brother gave me. We get the clearance we need. The taper mill we used. 14-Feb-07 Squaring the truck frame to the table to add more clearance between the wheels and frame. 14-Feb-07 using a long bit to add clearance for the wheels. Machining the spring hanger arms. 1-Aug-07 Machining the Equalizer arm again. This one is bronze instead of aluminum. 1-Aug-07 I was not convinced the original aluminum arms could really take the weight and wear, so I purchased replacement bronze arms from Bob Pederson at RailroadWarehouse, the supplier for the Heavy Mike castings and blueprints. The bronze arms are much more substancial. Checking the centerline and hole placement before drilling. The casting had a slight twist in it, like all castings of long thing parts do, so we shimmed it in the vise to get the holes to line up where we wanted them relative to the centerline of the casting. Milling a slot in the one end. A blurry action shot of the machining operation and the bronze chips shedding from the cutter.

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