Rolling Stock for the Garden

[JimG]

A few weeks ago at the S scale Autumn Meeting, I swapped a Mike Williams G3 wagon kit for two 1/32 scale wagon kits. The kits were a combination of underframe kits and one piece resin bodies with work being started on one of the underframes. Both kits are of a GWR two-plank wagon - not very Caledonian but I am intending to have a fair mix of other companies' vehicles on the layout so these two wagons would be the first "visitors".

The underframes are from the Old Originals stable...



...and provision is made for various forms of springing on the etch.



I want to fit a similar system to that which I've used on my S scale wagons so I will have the axle bearings sliding in the "W" iron slots and I will extend the slots by cutting round the semi-circular etched line above the existing slot.


The first thing was to design a carrier to hold the bearing behind the "W" iron and I started off by trying out various sizes cut from styrene sheet.



This was the final design before going to metal...


...and here are the four carriers being cut from 12 thou nickel silver...


...and the finished parts at the end of the cutting process.


I also decided to turn up my own axle bearings since there would be about a 2mm gap between the Slater's bearing (shown on the left) and the boss on the wheel face.



The first job was to solder a small piece of brass angle just inside the bottom edge of the solebar . This would perform the dual function of guiding the top edge of the carrier and providing a lower end stop for the carrier.


The next job was to solder two spring supports made from brass angle drilled with 0.8mm holes to hold the spring wire. The supports are 40mm apart to be used with 0.5mm spring steel wire which will give ~1mm deflection with a wagon weight of around 200gms. The spring data was worked out using Russ Elliot's formulae on the CLAG web site.


At the same time as the spring hangers were being fitted I was also working on the studs on the bearing holders which would act on the spring. I started off with 0.9mm wire soldered in a hole in the 12 thou nickel silver, but that didn't seem strong enough to stand up to the rough and tumble when running since the joint would break fairly easily with a bit of finger pressure. I machined up some 2mm rod with a 1mm end to go in the hole in the carrier and that was much stronger but there was also the problem of the possibility of the spring wire going over the end of this rod. So MkIII is shown above with a 1mm diameter stub to go in the bearer hole, a 2mm diameter body and a 3mm diameter flange to keep the wire in place.


Here are the four bearing holders with the MkIII studs soldered in.

With all the messing around with the studs, I had to adjust the settings for the spring hangers so that there was just a small amount of pre-load on the spring, but not too much that teh rate of the spring was altered too much. It became a bit empirical, with a fair bit of unsoldering, filing and re-soldering until I got a good setting.


Here's the full assembly with the spring and carrier in place.



The last to fit was a small clip at one end of the spring so that the bent end of the spring could be clipped under it to retain the spring in place. The spring is held in the clip quite loosely and there isn't any effect on the normal action of the spring.


The chassis with its wheels in place and all working as designed. I've still to cut out the semi-circular extensions in the axle slots in the etch to give full length movement of the springs and bearings and I'll do that in the morning

The white rings at the back of the wheels are spacing washers cut from styrene to adjust for the Slaters wheels which have been re-profiles to ScaleOne32 - a temporary measure until I get something better.

Jim.

 

[Dikitriki]

Hi Jim,

That's super work, and shows what a versatile machine your miller is.

And of course you can copy the designs as often as you need

Richard

 

[JimG]

That's super work, and shows what a versatile machine your miller is.

And of course you can copy the designs as often as you need

Richard,

It was also an exploratory run for producing "W" irons on the mill. I was intending to do artwork for an etch for 1:32 scale "W" irons for some Caledonian wagons when I thought that doing it on the mill might be feasible. I actually got a sheet of 28 thou nickel silver from Eileens a short while ago with "W" irons in mind but hadn't actually got round to doing anything. Springing these underframes gave me a chance to explore the possibilities and it has worked out well so far.

Jim.

 

[JimG]

I managed to file out the crescent shaped parts at the top of the axle slots this morning so that the bearings can now have about 3mm travel. The fixed axle position is +1mm on the lowest point so the provision on the kit allows for 2mm movement above normal - more than enough for some bad trackwork.


The underframe was loaded up with the resin body, the ironmongery with the kit and a piece of sheet lead under the bag of bits to bring its weight up to around 200 gms. The Slaters wheels and axles weigh in at 47 gms, so I've got the body weight just about right. Not included are bits from the etch - like brake gear parts and couplings - which will add another gram or two.


Before filing out the axle bearing slots I marked up the fixed centre on the "W" iron with a couple of scratches either side of the bearing, and the sprung centres are pretty well spot on with the calculated load. So another thumbs up to Russ Elliot's spring formula. I've used it on my S scale wagons and four wheel coaches and it has worked very well with them as well.

Normally I would use fixed values for weight and distance between spring hangers and use the wire diameter as the variable but in this case I had several yard lengths of 0.5mm spring steel wire which I had got many years ago for some other project and I'm trying to use up materials that I have accumulated over the years to try to lessen the pile before I shift off this mortal coil. The brass angle and strip used in the spring assemblies were got from John Flack (remember him?) many years ago.



So I set up a small spread sheet to work out combinations with the 0.5mm wire to give me 1mm deflection. The first column applies to the present wagons under construction with 50gms per wheel and 40mm between hangers. But I would rather get the distance between hangers in to around 36mm so that they can sit on the ends of a normal "W" iron, so I'm looking at going up to 70 gms per wheel for subsequent wagon construction if I still want to use the 0.5mm wire. This may be going too heavy, but I do remember someone experimenting with springing in Scale7 back in the 90s and he recommended quite heavy wagon weights to get the best performance out of the springing.

Jim.