Passenger Truck Question

[EZnKY]

One of the biggest differences between the Ohio Falls trucks and many of the other prototypes out there is the use of flitch plates for the side beams.  You can see them in the photo.  On one of the trucks at Mammoth Cave the flitch plates were flush with the wooden beams, but on the other they were proud by about an 1/8 of an inch.  I chose to model them almost flush.

[EZnKY]

I cut them from 0.015 brass strip, and then drilled lots and lots of little holes for the various fasteners.

[EZnKY]

Once I had the flitch plates fit to the frames, I glued the upper wooden wheel guards between the transoms and the end sills.  That completed the basic truck frames, and that's where I am today.

[Ray Dunakin]

Beautiful work. I like the weathering on the wood parts, it looks like something that has a few years on it yet is still in good shape.

[EZnKY]

Had a good weekend and was able to get quite a bit done on the trucks.  (And still mow for the first time this spring, clean out the planter beds, and a few other honey-dos.)
I worked on two things:

1.  The pedestals for the journals.  Accurately placing these will be the most critical thing to make sure the trucks track well without wobbling or "hunting."
2.  The swing motion.  I'm working from the inside out on the trucks to make sure I can get to the bits and pieces as a finish and assemble everything.

I started with the spring plank.  I was able to use the laser cut piece from the Hartford kit, but I needed to narrow it by a scale four inches since the transoms are closer together due to the shorter wheelbase than the Colorado prototype.  I also needed to move the mounting point for the yokes that hold the spring plank.  The transoms are much deeper on the Ohio Falls trucks, which lowers the yokes by a corresponding distance.  This also shifts the mount point for the yokes from the sides of the spring plank to underneath it.  You can see this on this photo of the underside of the trucks at Mammoth Cave.

[EZnKY]

I made the new brackets for the underside of the spring plank by soldering a short piece of round brass tube inside a piece of square tube.  A couple of NBW castings and some CA secured it to each plank.  I drilled out the inside of the tube on each end and tapped them for 00-90 machine screws. 

[EZnKY]

I dressed up the Hartford spring castings by scribing lines on the edge to indicate the different leaves of the spring sets, as well as the joints between each spring set on the hinge pin that connects them.  We'll see how clearly this shows up when I paint them.

[EZnKY]

I cleaned up the yokes and yoke hanger castings to remove parting lines and temporarily mounted them to the undersides of the transoms.  You can also see that I'm painting the pieces with A.Mig 2005 black primer as I go.

[EZnKY]

The pedestals were next, and since they literally identify the trucks as Ohio Falls products, making them is probably the most important part of this little project.  The left pedestal on each side of the trucks has the name of the make along the top, and "No. 11" below, which I presume is the casting number for that size pedestal.  The right pedestal on each side only has the number, which means I needed to make four of each type. 

[EZnKY]

I decided to approach the pedestals similar to the wheelsets, photoetching a brass overlay to put on top of the Hartford castings.  So far this is the most detailed photoetching I've tried, and I think it came out fairly well.  I followed the same process as before by creating the masks in CAD, photocopying them on a special blue transfer film, and then laminating the blue film to the brass. 

The pedestals came out of the etch tank looking like this.  (You can see where I used black Sharpie to cover flaws in the blue mask.)

[EZnKY]

There are a few locations where the etchant started to erode the sides of the lettering, so next time I will increase the line weight a little on the drawings to compensate.

I cut the overlays from the fret and cleaned up the edges with files.  I also had to file the cast details from the front of the Hartford pedestals to create a smooth surface for the overlays.  I tried a couple of different glues using scraps and found a very thin CA provided the best bond once both surfaces were cleaned with alcohol.

[EZnKY]

After the glue had set overnight on Saturday, I filed the edges of both the overlays and the cast pedestals to make sure everything aligns and looks like a solid piece.

[EZnKY]

I made a little jig out of MDF to hold the front and back pedestals in position and epoxied brass spacers at the bottoms of each leg.  The pedestal brace that runs along the bottom will be attached to these braces.  I also formed a simplified fillet at the joints with epoxy so they look more like a single casting.  I think some paint and weathering will make it more believable.

I had problems with the first attempt getting stuck to the jig, so I shaved a bit off the top and used a narrower brass spacer to get back to the correct height.  This formed a small void at the interior corner between the pedestals and the braces that kept the epoxy from sticking to the MDF.

[EZnKY]

Here's how they look on the truck frame with a thin coat of primer.  You can also see I've started attaching some of the hardware to the flitch plates just to see how things are going to look.

[EZnKY]

And that's where I am today.  I wish the lettering was crisper on the pedestals, but not enough to do it all again.