My expierience with big locos

[modelsof1900]

The rods didn't stay in their sunk holes.

If possible, remove the rods and the black plastic sheet, then solder the rods to the brass sheet through which they pass - you may have to remove or modify the bent-over ends. After doing so, you can then cement the black plastic back in place.

Doc, I think that this will not work. The bolts must be movable at the gliding plate. This plate will swing if the engine rolls into a bow. And there is a many more difficult problem if engine and tender moves literally against one another, in a switch connection as a sample.
But I do not have an idea for realisation, sorry! Maybe however that these bolts should be moveable connected to the pressure plate like heavier eye bolts?

[doctorwayne]

Perhaps I've misunderstood the set-up or misstated my suggestion: If the bent-over ends of the rods are supposed to remain in their countersunk positions, then simply cutting off the bent portion and soldering the rest to the brass plate at the front of the diaphragm should keep them in place. You could then enlarge the holes on the front of the tender itself to allow movement of the rods when the diaphragm pivots, as shown in the photo below. The black plastic plate could be cemented back into its original position:

   

If you require more movement, drill-out the rods vertically near their ends, as illustrated below, then pass a phosphor bronze or stiff brass wire through each hole. Bend each wire into a tight "U"-shape, as, shown, then drill the brass plate to accept the free ends of the wire. Slip the wires through their matching holes in the brass plate, bend-over the protruding ends (leaving a little space between the end of each rod and the surface of the brass plate) and solder the wires to the brass plate. This will form a loose-fitting hinge at the front end of each rod.

   

A more elegant version could be had by adding a bracket above and below each rod on the rearward-facing side of the brass plate, and slipping the pivot wire through all three pieces and soldering the wire to each bracket.

Wayne

[Schraddel]

Hello Bernhard and Wayne,

thank you for your efforts and thoughts you made. Some of your advices i have picked up, so e.g. the enlarging of the bores. But the soldering of the rods fixed onto the head, that will not work.
Sometimes you have to rethink a device, here it was to modify the existing device to make it work. The bend ends of the rods were clearly a failure.
- The ends have to be the shape of a somewhat "knob".
- This knob must be moveable as the angle of the guide rods, in relationship to the diaphragm head, will change whenever the loco begins to negotiate a curve.
- The knob must not slid out to the rear
- The knop must not slid of forward
At least i found a solution:


Here the bend ends of he rods were removed. Instead some pieces of 0,2mm brass sheet were drilled with 0,8mm (the diameter of the rods).
Those pieces were then soldered onto the ends of the rods. Mounting the rods into a drill chuck, take a rasp and make them round, here it is about 2mm. This will be a kind of an knob, a very flat one, but a knob.
Next take a milling cutter, one of this very small face cutter and mill
a) the styrene plate complete thru
b) the brass head end to a countersunk depth of app. 0.8mm.
This will guarantee the knobs have the movability they need and will prevent them to slid out to the rear.






Then make some bucklers out of the 0.5mm black styrene. Glue them with some styrene glue onto the sunks. But beware, that the knobs hav still enough space to take movement action. So the bucklers will not be pressed in flush. The overlaying can later, when the styrene glue is completely dried out, filed flush to the surface.
The use of styrene glue prevents the rods of going sticky or even solid, as the sort of glue does not adhere on brass.





One of the tasks was the repositioning of the coupler bolt, according RP37, to get an optimal loco to tender distance. Here it was simplier to make a new one out of brass stock.





So the modified plate looks like.





Next was test running.





Taking a Atlas #4 switch. This switch is in an industrial spur were such big loco do not belong to.





But she was able to take the #4 switch and the reversed curve. Here the limit is reached and you can see the start of gaping.





Another industrial spur. Here is the very limit. And this limit is determined by the long rigid wheelbase of the four coupled loco with it's 73' drivers.
The nuts on the rear end of the rods were after the test running secured by a little drop of AC.

My opinion, if this works in tight curves of industrial spurs, so it will work on mainline stretches with more gently curvatures too.


Cheers Lutz

[modelsof1900]

Lutz,
nice to read that you have found a workable solution!
Wish you success for next steps and enjoy with this model!

[doctorwayne]

I agree: that's a very nice solution, and should stand up well in service.

Wayne

[Schraddel]

Meanwhile i started the task equipping the 4-6-6-4 L-105 with a diaphragm too.


Here i have no help in shape of a brass casting. So i had to built it all from scratch.





The diaphragm head was made out of 0.5mm black styrene sheet and in this case hinges were made.





The hinges were glued onto the back of the diaphragm head with CA.





Then put together according the example ot the 4-8-4 M-68.





Theoretically it should work, not yet testet now.


Cheers Lutz