Speeder and hi-rail wheels

[sirenwerks]

This is a long shot but does anyone make spoke-d wheels for speeders and speeder trailers and hi-rail wheels, or made them?  I'm hoping for working wheels, as I want to explore real small moving things.

[narrowminded]

Here is something I've done in the course of developing my Nn3 projects.  The small wheels can be printed BUT... printed or not, weight in the devices this small is a very real issue.  If you look through that thread you'll see one of the real little wooden mine cars I was working on and while it could be made it was sooo ridiculously light that there was no way that a train of them could be made to function.  They literally could be blown off the track in a small wind.  A solid metal weight filling the cavity might work but all cars would have to be run with "full loads" all of the time or just used as static display pieces. 

The Nn3 tipper cars earlier in that thread with 24" metal wheels and axles (33" Z scale wheelsets) worked fine and tracked fine but were about as small and light as could be expected to run reliably.  The bigger and all metal wheels and axles are what allow them to work but I think that package is at the limit.

If they were used for pilot wheels where a solid brass frame pivot piece could be used that might also be made to work but it would always be subject to the specifics of the application and the room for the hardware.

https://www.therailwire.net/forum/index.php?topic=46301.msg604401#msg604401

[peteski]

Micron Art (now defunct) made a photoetched brass kit #2013 "N scale hand-cars".  It includes NWSL 28" wheelsets, and etched spoke inserts to go over the wheel faces.


Micron Art kits show up on eBay from time to time, and Reynard's (company owner's) wife  sells the remaining Micron Art inventory on eBay. At least she was some time ago. See https://www.therailwire.net/forum/index.php?topic=47305.msg698620#msg698620

[sirenwerks]

Here is something I've done in the course of developing my Nn3 projects.

Those are beautiful.  The wheels I seek are 20" so those are close enough for me.


Did you ever consider printing them in metal through Shapeways?  Or would that be too minimal of a weight gain?

Micron Art (now defunct) made a photoetched brass kit #2013 "N scale hand-cars".  It includes NWSL 28" wheelsets, and etched spoke inserts to go over the wheel faces.

The 28" seems a bit large, but I will check them out.  The problem is I need a quantity of them.  I was thinking, however, if etching a series of layers with a shared center hole for an axle could yield what I need, like stacking washers.

[Jim Costello]

Have  a look at some of the British manufacturers like Graham Farish,Peco or Parkside Dundas.  I remember years ago Parkside had a
range of both spoked and disc wheels . The 2mm Society may be of help as well.

Jim

[Simon D.]

Most British N Gauge wheel are actually bigger (1:148 over 1:160).  The smallest diameter wheel 2mmFS do is 5.25mm = about 34" according to my calculations.


You could try some of continental makes?  I know almost nothing about them unfortunately.

[up1950s]

Shapeways  https://www.shapeways.com/marketplace/miniatures/trains?type=product&q=mow+wheels

[Maletrain]

It seems like if you really need something to roll well on track, it needs to have smooth treads and flange surfaces.  I don't see getting smooth surfaces with either etches or 3D prints.

But, making rough shapes with etches or prints and then facing them on a lathe or even a drill might make things work much more reliably.  That is basically what the prototypes did with cast steel wheel blanks.

And, if cost isn't a limiting factor, making the bodies of tiny mine carts could probably be done by casting metal into silicone molds made from plastic or even wood masters.  Making bottoms and flat sides separately should be doable to avoid any need to vent complicated molds.  And then the flat pieces could be assembled into models that weigh much more than the masters. 

If you really need high detail on the parts, it might even work to make the castings with epoxy, and set flat metal plates into it before it hardens.  Then details would be formed and glued to the outsides of the flat metal parts all in the same step.  Probably easier than melting and pouring low-temperature alloys like CerroSafe, and cheaper, too.

[narrowminded]

It seems like if you really need something to roll well on track, it needs to have smooth treads and flange surfaces.  I don't see getting smooth surfaces with either etches or 3D prints.

Much to my surprise those wheels actually rolled quite well.   The axles were .015" SS spring wire glued into the wheels with CA.  The whole thing rolled and tracked really well.  But the assembled weight was an issue and further aggravated by that particular car design's short wheelbase and large overhang at each end.  I'm also not sure that the same wheels in nickel silver would have been much better because of their miniscule size.  The tippers that worked well had brass 24" wheels and 1.2mm axles which makes for a pretty large change in volume, therefore weight, with all else being equal.

But, making rough shapes with etches or prints and then facing them on a lathe or even a drill might make things work much more reliably.  That is basically what the prototypes did with cast steel wheel blanks.

Wheel inserts for metal wheels could be made and having a lathe for minor touchups would certainly be handy.  I've actually planned on doing just that but have also been adding in house capabilities for miniature parts that include CNC mill, injection molding for plastics including Delrin and ABS, as well as live gear hobbing.  That's a big part of why I haven't been around much lately.  A good part of that is travel and life issues but what time has been available has been spent on developing these machines with modelling in mind.  Another reality is that most if not all of this it has to be done as a hobby because, in general, the volumes and costs would be prohibitive as a viable business.  But it's what a retired machine guy does as a compulsion.

[Chris333]

Instead of gear hobbing wouldn't it be quicker to mill gear sticks and slice them to width? It is what NWSL does.

[narrowminded]

Instead of gear hobbing wouldn't it be quicker to mill gear sticks and slice them to width? It is what NWSL does.

You can do that with live hobbing.  Basically make any length you want limited only by the ability to support the length (and the machine's travel, same in both methods).  What you can't make with a dividing head and special ground single tooth hob is proper worm gears where the worm wheel tooth wraps around the worm to the depth of the gear mesh.  Then making proper bevel gears where the tooth is cut at an angle.  The error introduced with small angles in light duty can be tolerated but it's not really right and can also become very noisy as the angle is increased.  A live hob handles this as once again, the cuts are made in the exact fashion that the mating gears will mesh in service.

One of the biggest advantages of live hobbing is that one hob will make any diameter gear with all of the involute angles being perfect, not depending on the exactness of the involute grind on the various cutters needed for different numbers of teeth nor the exactness of the tooth advance divisions because the tooth angles are generated exactly the way they will run in service.  Makes for a more precision gear which runs much quieter than one running with variations, the amount of the variation directly effecting the amount of noise.  That precision will also add strength which can afford adequate gears in smaller sizes, especially with worms.  For our purposes the needed strength for the sizes used is seldom challenging because they are generously oversized for the service, but the noise can be an issue and any desire to make smaller components is limited.

The disadvantage of live hobbing is the initial complexity of the machine elements required.  After that it's all downhill. Simpler hobs, much higher productivity, accuracy, etc.

[narrowminded]

Those are beautiful.  The wheels I seek are 20" so those are close enough for me.

I made 18", too.  20" could be made but with all of the caveats already outlined. 

Some of the speeders I measured had 16" wheels and that with other issues convinced me to not pursue an operating "N" scale Speeder.  HO?   Maybe!