< Wheel Assembly >
The front axle is equipped with one eccentric for axle driven pump, while
the back axle has four eccentrics for Stephenson valve gear. Gunmetal is
preferable as a material for the eccentrics but I employed brass because
of lower cost and easier cutting.
The eccentrics for the valve gear have single side flanges which can be cut by knife tool. The photo shows using 'wobbler' to allign the eccentric axle hole in four-jaw.
The eccentric for the pump has double side flanges. The driving circle is cut by parting tool.
Each eccentric is fixed around an axle with a set screw. Note the eccentrics for valve gear have screw holes in their flanges. It is due to adjusting valve phase after assembling valve gear set. After the adjustment, I will secure the eccentrics for valve gear with taper pins.
The cranks are laser-cut from 12mm steel bar. The distance from the wheel axle to the crank pin should be exactly the same in all of the cranks. I finished one crank and drilled other cranks through the first one, with the consequence that the first one's hole was a little expanded! I recommend to prepare a drilling jig instead of utilizing one crank as a jig.
Crank back face is thinned in part so as to clear the axlebox. After that, a crank pin made from silver steel bar is glued in the hole with Loctite.
Before assembling the wheel parts permanently, I painted the wheels, the axleboxes and the cranks. With simple masking, I painted them with heat-resisitant black splay paint and annealed by infrared heater.
The wheels are glued onto the axles with Loctite. Before that, each face is degreased by acetone.
The quartering is done in the lathe. Each crank is locked on the axle by a set screw. Both crank pins are aligned with a suitable blocks at both ends.
So as to fix the cranks permanently, I used taper pins, drilling straight hole and expanding it with a taper pin reamer.
The wheel sets are completed. Outside faces of the cranks are not painted yet. I will paint them in the same color as the loco body. For the present, I intend to paint red.