< Brake System 1 >
The brake system of C53 locomotive is peculiar.
Leverage connection spreads vertically instead
of horizontally. Both 1st and 2nd brake hangers
are between 1st and 2nd wheels. On the other
hand, there is no space between 2nd and 3rd
wheels. So the 3rd brake hangers cross over
the 2nd and 3rd wheels from outside. The
following CG shows modeled brake system without
wheels and main frames.
I intend to employ working steam brake for the engine, in addition to a typical hand or foot brake for the tender. In order to prevent wear of wheels, the brake shoes are made of aluminum castings, and section of the brake shoes traces wheel contour as same as the prototype. In this case, the brake shoes must follow the wheels' side play. So the connecting pins in the hanger must be enough loose to allow the hanger to tilt in side direction.
I started from the brake shoes. With a chemical wood pattern made by MODELA, I ordered aluminum castings of 12 brake shoes including a whole spare set. Incidentally, if the wheels are not large, the brake shoes castings can be arranged in a diameter of the wheel, then the whole jobs can be turned in the lathe at a time.
I utilized the large face plate for wheel cutting again. After finishing top and bottom face in three-jaw, the castings are separated and bolted onto the face plate in a diameter of the driving wheel. I start cutting with arc steps in top face of the castings.
Here I made a tool for cutting the flange shape of the tire contour. A high carbon steel rod is turned in a desired shape, cut half round by end mill, hardened, tempered and oil-stoned.
The castings are reversed and bolted onto the plate. The straight tread face is taper-cut by a boring tool. After that the flange shape is cut by the made tool.
The brake shoes are finished by slitting with end mill. A number of parts could be finished in comparative short time, because the aluminum casting is very soft.
Next I made all kinds of brake rods with forked ends and eye bolts, except the last pair with U-shape castings. Large brake arms will be connected to the castings. Note the rod diameters are different in one another (1st < 2nd < 3rd), because the braking force is accumulated by the leverage.
The forked end is made from laser-cut flat plate, bended with the jig that I used for the wheel spring bracket. The photos show the jig without and with the job. After bending, holes for connection are opened.
The photo shows cutting the U-shape cast iron. After finishing the thickness, inner pocket is cleaned by end mill. A die block will fit along the pocket and be connected to the large brake arm.
All of forked ends and the others are silver soldered onto ends of the rods. So as to hold the job firmly during the soldering, the rods and holes are threaded. Note a fine groove is cut across the thread. It helps silver solder to flow through the thread. Care must be taken to silver solder cast iron, for its repelling surface and heat denaturation.
Hakuba Mini Train Park
In October I visited new 5 & 7 1/2 inch dual gauge track layout "Hakuba Mini Train Park". Hakuba is a famous skiing ground in Nagano. The layout was constructed cutting a path through the thick forest. It provides unique and nice feeling like a logging railway. Total track length is around 1000 meters. The layout has a station with four platforms, steam shed and traverser. The last photo shows a devise for connection between offset-reversed tracks.