This is a fixed pilot, Kadee coupler conversion parts set for a Williams GP9. Front and rear pilots with coupler mounts and detail parts are included.
This parts set consists of front and rear pilots and various detail parts. The pilots are intended to be bonded to the underside of the chassis. The various air hoses are separate parts, to facilitate painting and weathering. The cut levers are part of the pilots and are fixed. The coupler mount is integral with the pilot.
Please note that due to their small size and intricate details, the pilots and detail parts are fairly delicate, and should be handled carefully. The coupler mounts, which handle the actual load, are quite sturdy.
This parts set is designed for a late 1990s Williams GP9 as shown here. It should fit different road names of the same model. It may fit other more recent GP9 models, as well as other Williams models using a similar stamped steel chassis. Please see the detailed dimension drawing here to verify that it will fit your model. In particular, please verify that the chassis height is within +/- 0.025” of the indicated value, as this will ensure the correct height of the couplers once they are installed. Please note that in addition to removing the original couplers and pilots, it may be necessary to remove the coupler mounting feature at the front of each truck, in order to clear the rear of the coupler and mount.
The coupler mount and the coupler position relative to the pilot are designed for a Kadee 740 coupler. Other couplers using the same mounting pattern should also work. I recommend bonding the coupler gearbox and cover together to ease installation and removal. Minor coupler height adjustments are possible using shims. The height of the mount is designed so that a nominal installation will require one Micromark O gauge Kadee shim (or equivalent 0.025” shim).
The Frosted Ultra Detail and Frosted Extreme Detail materials utilize a waxy support material that is dissolved after printing is completed. Because the support material slightly changes the texture of the product, and isn’t applied to the entire product, you may see some slight variability in texture over the surface of the model. Also, although the parts are ultrasonically cleaned by Shapeways prior to shipment, not all of the support material is removed. This may obscure fine details and results in poor paint adhesion. I recommend a 10 minute bath in acetone, followed by gently blowing fine holes and details dry with an air nozzle or empty airbrush. This will remove the wax substrate and provide a good surface for painting.
Next, check that the front and rear ends of the chassis are flat and level. The stamped steel is quite flexible and may not be true. Take measurements longitudinally and laterally at each end of the chassis. True it by bending gently or, if you have the engine completely disassembled, by putting it on a flat surface. The pilots will not bond well otherwise and will visually accentuate any defect in the chassis.
Finally, check the fit of the pilots to the chassis before painting and assembly. If it doesn't fit readily, please don't force anything! I have provided several features on the parts to locate them on the chassis. Due to manufacturing tolerances of both the chassis and the Shapeways part, it may be necessary to make some minor adjustments before installation. If so, use a small needle file on the locating features to adjust the fit.
The detailed assembly sequence for this kit is as follows:
- Remove the original couplers, hardware, wiring, and pilots from the trucks.
- Fit check the front and rear pilots against the chassis.
- Prepare the coupler mounts by tapping the four holes in each pilot using an M2x0.4mm tap. (A #2-56 tap may be used instead, if preferred.)
- Clean the parts in the kit as described above.
- Prime/paint and install detail parts on the pilots as desired.
- Prepare the mating surfaces of the pilot and chassis by wire brushing and cleaning with acetone.
- Bond the front and rear pilots to the chassis. Gap-filling CA glue works well.
- Install each Kadee coupler and its shim using four M2x0.4mm screws. Ensure that the screws are long enough to provide substatial thread engagement in the mount.
- Check the coupler height and adjust shims if necessary.
V1: Initial release.