Advice on constructing a tipper

[duttonbay]

I am contemplating building an 009 (or HOn30) layout based on the Stannary Hills Tramway in Queensland (Australia). A previous attemmpt in On30 stalled for various reasons. I will need a number of tipper wagons (although it's not clear to me that they were ever tipped, rather unloaded in a "tumbler" above the mill. They have wooden frames (built at the tramway's workshops) while the tipper bodies came from Koppel.

I am wondering whether anybody knows whether these could be 3D-printed, and whether there is anbody prepared to custom draw and print these?   Oh, and another question: a wheel diameter of 18 inches equates to 6mm in 009. Are wheelsets with that size wheel available?

Stannary Hills Ore Wagon drawing by duttonbay, on Flickr

Stannary Hills Falcon Arbouin by duttonbay, on Flickr

Hopper near Rocky Bluff by duttonbay, on Flickr

Hopefully clicking through each image will bring up a higher resolution version. Any advice gratefully appreciated.

[JulienW]

6mm wheels shouldn't be a problem. Light Railway Stores do the (currently out of stock) Greenwich 6.2mm disc and Mosskito 3 hole jobs (also 6.2mm). the Greenwich wheels are also available from Dundas (shown as in stock at the moment).

There's also Mathieson Models, but I've not used them, and doing a google search for "6mm diameter N-gauge wheels" brings up a few other hits, including some by Fleischmann so it might be quite a common size with a source that easier to access from Australia.

As to the 3D printing side I'm a complete novice so can't be sure just what is possible, but I'd suggest it may be better to source the wheels first to get the axle length and work up the CAD for the chassis from there, as I suspect the N gauge pin point axles will workout longer than the scale 2' gauge equivalents. My immediate thought would be to make the chassis wide enough to take the axles, but there's not a huge amount of clearance to spring them in place so that may mean some form of separate axle box attached to the underside of the sole bars to trap the wheels in place.

It might be worth thinking about inserting a brass bearing cup too, but that's going to add to the overall width.

With the extra width on the chassis to take the axles the question then arises about the bucket and whether to keep this to 1:76.2 scale or increase its size to be in proportion to the chassis - but that might loose some of the character.

Thinking a bit more about making these and assuming you'll be needing a fair number of these I wonder if a better solution would be to have the chassis cast in metal (brass or white metal) with the axle boxes being a separate casting (that could incorporate the bearing surface) or etched with a hole for a bearing cup.  If casting the masters could be 3D printed, but the metal chassis would give a bit of weight low down where needed and be a bit more robust if the wheel sets are to be 'sprung' into place (as 3D prints tend to be brittle in my experience).  I'd suggest etched break gear with the 'bucket' being 3d printed or resin cast from a 3D printed master.  it's probably not a cheap process to make what in effect would be a (commercial) kit, but if there were sufficient interest once you've produced enough for your own use the could be sold on to help cover your costs (though how much someone would be prepared to pay for such a 'mixed media' kit is hard to judge, and it then becomes a bit of a balancing act).

Hope that helps John.

[B.Meldon]

Direct link to the full B&W photo: https://livinghistories.newcastle.edu.au/assets/display/337687-max?u=

[duttonbay]

Thanks Julien,

All your points are noted, and perfectly valid.

One of the many reasons (of many) why the On30 version did not proceed was that a bloke told me he could produce something along similar lines to your suggestion, but then despite a number of emails nothing happened. His plan was to 3D print the chassis including (from memory) the axle boxes as a master to then cast in white metal, but to split the chassis into two at diagonal corners, so that when the halves were joined the wheelsets were trapped.

My On30 "prototypes" used the O14 tipper bin from RCL. Not exactly correct, but it looked the part. I guess I was hoping that in the smaller scale there might be an easier way, but weight was always in the back of my mind.

Back to the drawing board, methinks.

[clayliner]

"weight was always in the back of my mind."

Always an issue with small wagons like this, I think. If you can run them loaded, of course, they will be heavier and probably run better. You can make mineral loads with domestic filler, which if you're careful can be removeable. If you can incorporate a small lump of metal within the filler the loads will be even heavier (and if it's ferrous metal you can use a magnet to extract the loads!)

David.