Does Anybody Make a "Working" N Scale Switchstand?

[C855B]

The crank arm needed to turn 90 degrees on an indication only stand is nominally .028" with zero play in the pivots and based on a .040" throw. ...

Yeah, my numbers were pretty close to yours. The slop in the tabs on the points is somewhat vexing. Figuring on overtravel to hard stops in the switchstand itself with spring relief is maybe something we could manage with finer wire. I have some .010" phosphor bronze in a box somewhere for handrail projects and maybe should use that instead of the music wire for testing.

Yes, servos, but the way I've integrated them into the turnouts leaves nothing other than the throwbar to tap for moving the target. The throwbar is hard linked to the servo horn with no spring action, relying on the station-keeping function for points pressure.

I've been working on a scale 3D-printed lantern for a while:



It won't meet Shapeways' specs currently, but when I get the round-tuit to revise the artwork the intent is to try for illumination, 0.010 fiber or 0201 LED as you guys mentioned, using the 0.018" tubing ngineering.com has. I think it's doable.

[narrowminded]

If you proceed with the approach you had in your video this might make your life easier.  When bending your wire to make the throw arm, instead of trying to get the Z bend/ throw offset right at a number (like .028"), bend a comfortably larger offset that's easy to work with and will leave you enough material in the center of the arm to bend it again at roughly 90 degrees (whatever it takes) bringing the two verticals back in to the dimension you're seeking.  It will make getting accurate throw C/L's much easier, set very accurately with your calipers, and will also make them adjustable for the variations in the switch throws, corrected by how far you bend the arm.  On installation you could measure the throw at each switch and then calculate the C/L needed, set it accurately with your calipers, and you should be good.  The target must go on last, aligned in place. 

Edit add: In case you didn't know this method, easy to do trackside with your calipers and a pocket calculator, the throw you'll need will be the travel of the switch x .7071".  Add one wire diameter and you've got your crank arm number to the outside of the wire and to the tenths of thousandths.  I won't tell if you round it to the nearest thousandth.

[bman]

I've a couple of sidings on the Plywood Panhandle where I use NJ International switch stands on my Atlas code 55 turnouts.  I used a small piece of metal wire bent into a flat "U" to connect the stand to the switch then a bit of AC to hold it all in place.  It was a bit of trail and error to get the wire the right length to throw properly.

https://youtu.be/_76QJEzscMA

[alhoop]

Yeah, my numbers were pretty close to yours. The slop in the tabs on the points is somewhat vexing.

I don't understand unless you are using the turnout throw bar to actuate/turn the switch stand indicator.
Not a good idea IMHO.
The servos I've used are precise and repeatable. Would think Tortoises would be the same.

Instead of trying to illuminate the switch stand indicator why not use a dwarf signal in conjunction with the switch stand
or in lieu of same?
Al

[spookshow]

Micron Art used to make a so-called "Archimedean Ground Throw" (not sure if they still do) -



I don't know if you literally need to be Archimedes himself to put one together, but it probably couldn't hurt.



-Mark

[Maletrain]

I don't understand unless you are using the turnout throw bar to actuate/turn the switch stand indicator.
Not a good idea IMHO.
The servos I've used are precise and repeatable. Would think Tortoises would be the same.
Al

I would think that it is a lot easier and more robust to throw the points with something other than this tiny position indicator we all want to make, and then let the throwbar move the indicator.  Much less force involved on the indicator mechanism if all it needs to do is swivel a target by 90°.

Thinking outside the box for illumination: how about painting the lantern "lenses" with flourescent red and green paints, then shining a UV "black light" on them from the side that the engineer sees.  That way, the only part flourescing would be the lens aimed at the engineer, and the other lens would be dark.  That would only work in the dark, but lanterns on real railroads did not seem visible in bright daylight, either.

[alhoop]

The more I think about trying to get a protypical sized  operating and illuminated switch stand in N-Scale it seems to be
an exercise in futility, especially if more than a couple are contemplated.
If successful a wall of protective plexi-glass will have to built around it and there goes the prototypical look.
From someone who has snapped off his share of signal posts.

Al

[Maletrain]

Actually I was thinking of using a hollow shaft (stainless steel hypodermic tubing with a magnet wire (only one needed as the tubing would be the other pole) feed through it.  But that is just me fantasizing.

 

I have been thinking about that for scale lamp posts.  Do you know of a source for that tiny SS tubing?  [Having already bought grow lights for early-starting garden seeds and a ±0.01 gram precision scale for scaling cooking recepies, I am sure to be on the DEA surveillance list anyway. ]

[DKS]

 

I have been thinking about that for scale lamp posts.  Do you know of a source for that tiny SS tubing?

http://ngineering.com/

[C855B]

For @alhoop and @spookshow : https://www.therailwire.net/forum/index.php?topic=40197.0

... how about painting the lantern "lenses" with flourescent red and green paints, then shining a UV "black light" on them from the side that the engineer sees.  That way, the only part flourescing would be the lens aimed at the engineer, and the other lens would be dark. ...

I like your thinking. I already have UV lighting in the room, although it is not at a saturation that will make small spots of paint "pop". Maybe UV loco headlights?   Seriously, one of the main features I'm after with the illumination is night operations. This is the quality UV paint, too bad the variety pack is out of stock: https://www.blacklight.com/items/WF170005KT .

If you proceed with the approach you had in your video this might make your life easier.  When bending your wire to make the throw arm, instead of trying to get the Z bend/ throw offset right at a number (like .028"), bend a comfortably larger offset that's easy to work with and will leave you enough material in the center of the arm to bend it again at roughly 90 degrees (whatever it takes) bringing the two verticals back in to the dimension you're seeking. ...

Genius! However, the bent wire is proof-of-concept only. The goal is a bit of fine tubing with wire or fiber, and the crank offset will likely be an etched arm on that. I still have to mull 90° stops with overtravel.

I've a couple of sidings on the Plywood Panhandle where I use NJ International switch stands on my Atlas code 55 turnouts.  I used a small piece of metal wire bent into a flat "U" to connect the stand to the switch then a bit of AC to hold it all in place.  It was a bit of trail and error to get the wire the right length to throw properly. ...

Nice!

[Lemosteam]

What about designing a small sleeve that fits over the throwbar, and centers it between the two turnout guides, design a small rack on top that would engage a printed gear mounted on the hollow tube which would be positively located from the opposite side of the guide.   The gearing would be designed based on the turnout travel which is actually pretty consistent.  The targets could be the last thing added to the tube to ensure the proper angles.

It might not be possible given the sizes and radii, but might be worth looking into.


Like this (Not to scale and ratio not calculated).  Throwbar and guides would slide into the rectangular holes and glued to each one respectively:

[Maletrain]

That seems like overkill design.  And, maybe pretty bulky to be strong enough if printed in FUD. 

I was thinking of a cast "body" that sits on one of the "guide ties" with a tab down one side to attach to the side of that tie.  The other side would extend over to the far side of the "throw-bar tie" and be raised a bit off of it, so that a wire with a bent offset of about 0.03" would allow it to go through the throwbar hole, bend to horizontal to go under the casting, and then bend back to verticle to go up through a hole in the center of the casting.  So, assembly would be easy.  Put the wire in the casting, put the lower end of the wire in the turnout throw bar, position the casing on the other tie, and add a tad of CA to fix it there.  Then put the indicator of choice on the top of the wire, positioned to properly align as the turnout points move, and CA it in-place.

Bending the wire consistently could be done with a jig.  Casting and drilling the body should not be too hard once a nice pattern is made.  A lantern indicator could also be cast. 

What I am having some trouble figuring is how to make the unlighted, flat indicators that have the horizontal red and upward angled green vanes.  Making something that has that 90° connection, fits on the wire, and does not look too thick seems hard.  Is there any sort of cruciform extrusion small enough to cut those from.  It might look a little off, but just gluing that to the wire might be OK.

Whatever design is finally desided on, I think it needs to be pretty cheap to make, pretty easy to install, and robust enough to last.  Otherwise, it is going to be used only in competition diaramas, not operating layouts.

[svedblen]

The gearing would be designed based on the turnout travel which is actually pretty consistent.

From the previous discussion I got the impression that the non-consistent travel, comparig one turnout to another, was actually quite a large part of the problem. Otherwise a really nice desgin 

[C855B]

I think you're going to run into issues with Shapeways' FXD minimums, if that's your benchmark. A variation of this idea of this may work better in etched metal. The solid rack-and-pinion is good work and would result in something durable. But Lennart is right, the biggest challenge is 90° end stops and spring connection between the throwbar and post for the overtravel to flex for the stops.

It stopped raining, so I need to get my butt out of the house and over to the studio to take those pictures.

[peteski]

 

I have been thinking about that for scale lamp posts.  Do you know of a source for that tiny SS tubing? 

I used to get my SS hypo-tubing from Small Parts Inc. They had a *HUGE* selection of those and lots of other useful items. But several years ago they got absorbed into Amazon and it is a format shadow it itself (and last time I tried to shop on their website was not fun).  N-gineering has some of that tubing too, but you can always Google "stainless steel hypodermic tubing" for some additional sources.