Because of my love for the Southern Pacific Cab Forward I have a large fleet of HO scale Rivarossi AC -10s, 11s & 12s. I have done a lot of detail work on my fleet, the Rivarossi Shell detail is very good but can be improved with brass detail parts. Among those improvements are illuminated marker lights. I wanted illuminated marker lights but the Rivarossi lights are way to small to work with. The commercial marker lights such as Tomar are too large. I bought the Cal-Scale non illuminated lamps because I can drill them out and install 1mm micro bulbs. A second reason for using the 190-280 marker is because they're identical to the actual SP markers used on the Cab Forwards.
This post will show my modifications to the Cal-Scale Brass Marker lights.
This is what I will start with. I don't have a need for additional marker lights at this time so I'm doing this for this post.
The picture below shows the 1mm 1½ volt micro light bulbs that will be installed in the drilled out brass castings.
My experience has been that the 1mm bulbs are not all equal, I measure the diameter for each bulb and drill the correct size hole for a custom fit. These two bulbs measure 1.33mm so I will use a #54 drill bit.
This is a closeup of one of the marker castings before drilling. As you can see in the picture the Cal-Scale detail is very good.
The drilling process is very tedious to prevent destroying the casting. I use a #80-#50 bit in a micro chuck with a ¼" hex shaft in my mini 180 RPM Black & Decker 4 volt battery operated drill/screwdriver. The low RPM is a must!
These particular 1mm bulbs measure 1.33mm so I'm using a #54 bit or 1.4mm for the rear hole. The castings will be glued to the face of the locomotive front cab so the slightly larger hole won't show.
Next is holding the brass casting for drilling. To accomplish that I sandwich the casting in my Panavise with a 1" x ¼" piece of pine behind the casting for support as shown in the picture below.
I begin by drilling a #60 hole (.040"/1.0160mm) completely through the casting, front to back. Drill half way through the casting then turn it over and finish the hole, that way the hole is centered properly.
Next drill the top hole down to meet with the first hole using the bit in a pin vise as this hole is very drilling, this forms a 'T' opening for light flow. Before drilling the top hole move the casting down in the jaws of the vise to prevent the casting from twisting. The downward drilling can twist the fragile casting if the bit grabs it.
In the picture below all three lens holes have been drilled out to 1mm
The Cab Forward marker light has only two openings with lenses so I will enlarge the rear hole to fit the bulb. In doing so you must reverse the enlarged hole on the second casting so that you end up with a right and left marker light! With Cal-Scale reversing the fixtures on their casting it's simple to get it right.
The castings are now ready to be separated from the sprue. I use sharp flush cutters that I bought at Harbor Freight. If you cut super close to the lamp head it will require very little filing. The wire coming out of the bottom of the fixture is very frail and needs to be turned 90° using long nose pliers. I've never broken a wire but I'm sure you have to do it right the first time.
Here the castings have been cut off the sprue and the cut edge filed. Using a round toothpick through the casting hole helps to hold the very small object during the cleanup process.
The castings are ready to have the micro bulbs glued in place. I use super glue to hold the bulb in place and also to glue the fixture to the locomotive.
I buy my micro bulbs in bulk off e-Bay and they don't come with insulation so I strip small leftover pieces of #30 DCC wiring and slip the insulation over the bulb wires.
The Cal-Scale 190-280 Modern Marker Lamps are ready to be installed. I don't paint them until I have glued them in place. I paint the lamp housing flat black to match the locomotive then just a drop of transparent glass dye in the lens opening. After they have dried a second drop will look like a glass lens.
The picture below shows a pair of illuminated Cal-Scale Markers installed on a Rivarossi Cab Forward, the number boards are also illuminated.
My most resent and most likely my last up grade to my fleet of Rivarossi articulateds was to use DCC Function #3 to turn on and off the marker lights. All of my Rivarossi Locomotives are wired for DCC operation including speaker equipped tenders for sound operation. All of them have been remotored with Rare Earth Magnet Can motors, six have a single Faulhaber 2224SR, seven have dual Canon EN-22s and three have a single EN-22.