Re: Rolling Stock for Banavie Road

ScottW

Western Thunderer
Jim,

Am I right in thinking that to get the vehicle at the correct height, and the bearing carrier sitting at mid stroke, you need to juggle with the diameter of the spring and the weight of the wagon?

Scott
 

JimG

Western Thunderer
Jim,

Am I right in thinking that to get the vehicle at the correct height, and the bearing carrier sitting at mid stroke, you need to juggle with the diameter of the spring and the weight of the wagon?

Scott,

Yes - that's about it. :) You may remember that I did a piece in the S Scale Gazette about springing using Russ Elliot's data from the CLAG web site whereby you can select the gauge of guitar string depending on vehicle weight, spring length, etc. (December 2011) However, I found from experience in Scale7 that
fitting springs then adding ballast to the wagon until the springs were at the correct height was a good method, with the ballast eventually being hidden as lead strip in the wagon underframe. So it can be a bit of a mix between spring selection and ballasting. Current thinking in Scale7 at the time I was fitting springs was to make the vehicle quite heavy to get the best effect from springing and I will be applying the same idea in S scale.

In the underframe I built to illustrate the Gazette article, I used Russ's formula to calculate the gauge required and it turned out to be pretty well spot on, with the springs in mid deflection where they should have been. I had made the underframe quite heavy, with brass section for solebars and buffer beams, so was going some way down the Scale7 thinking of a heavy weight vehicle, but I think I will add additional ballast to any further coaches and up the gauge of spring to get better running.

I suspect that in practice, since most S scale wagons weigh much the same in any case, that I shall ballast all my wagons to the same weight and work out the gauge of spring to suit this weight so that the same gauge of wire is used for everything.

Jim
 

ScottW

Western Thunderer
Jim,

Thanks for clarifying that, I'll have to re-acquaint myself with your Gazette article. I do remember seeing it but I think that I just browsed over it when I saw all the maths. ;)

Just over a month ago I added some lead to three Caley wagons I built, with adding lead only to the underside of the wagon I think they weighed in at around 2oz. One of the wagons was an open goods wagon with a 9' 0" wheelbase, the other two were short wheelbase mineral wagons. Despite the mineral wagons being slightly smaller the weight of them was only marginally lighter than the open goods.

Scott
 

JimG

Western Thunderer
Jim,

Thanks for clarifying that, I'll have to re-acquaint myself with your Gazette article. I do remember seeing it but I think that I just browsed over it when I saw all the maths. ;)

Just over a month ago I added some lead to three Caley wagons I built, with adding lead only to the underside of the wagon I think they weighed in at around 2oz. One of the wagons was an open goods wagon with a 9' 0" wheelbase, the other two were short wheelbase mineral wagons. Despite the mineral wagons being slightly smaller the weight of them was only marginally lighter than the open goods.

Scott,

I suspect that we will find a gauge of wire and a weight of wagon that works for us and will stick to that combination using ballast to adjust a wagon's weight to meet whatever combination is decided on. I will be looking at what weight of ballast I can get by filling the channel section in the base of the "W" iron assembly with strips of sheet lead. If this works it means we won't have to find other nooks and crannies in the underframe to plank the ballast.

I've just done a bit more modifying of the etches and I'm now looking at doing some trial etches of the modifications to see whether I can reproduce them in an etch. I'll see if I can do them in a smaller sheet - whatever PPD's minimum size is. I think I've worked out a way to assemble the bearing carriers and locate the springs easily and the trial etches will prove that - hopefully. :)

Jim.
 

SimonT

Western Thunderer
Jim,
thank you for the explanation. I too tried the Bill Bedford offering (soldered the wire to the carrier as the clamp didn't work) and the Exactoscale (the W-iron can flex outward allowing the carrier to drop out and unless the W-iron retaining tabs are folded exactly right they either make the non axle end of the carrier graunch, if tight, or let the carrier drop off the spring pivot if too loose).

I am building some 21Ton Minerals for Aberbeeg. Noone does a suitable W-iron for them so I am considering doing some etches. Would you mind if I adapted your design principle? I can already see another way of anchoring the spring that avoids having the tab sticking out where you might want to put framing or brake hangers. This morning I'll mock up a prototype to see if it works.

Simon
 

JimG

Western Thunderer
I am building some 21Ton Minerals for Aberbeeg. Noone does a suitable W-iron for them so I am considering doing some etches. Would you mind if I adapted your design principle? I can already see another way of anchoring the spring that avoids having the tab sticking out where you might want to put framing or brake hangers. This morning I'll mock up a prototype to see if it works.

Simon,

I have no problem with you adapting my design. In fact I might nick your wire anchoring if it works better than mine. :)

When using the Exactoscale 7mm "W" irons, I anchored the wire using insulation stripped from very small diameter electrical wire which I could push onto the wire ends and there was sufficient friction to prevent it coming off under usage. This meant that the wire only projected a small amount out of the side of the "W" iron at eah end, sufficient to hold the short insulation sleeve, and didn't tend to foul any underframe members. But with having to use smaller diameter spring wire in S scale, I couldn't find any small enough electrical wire whose insulation would stay on 0.008" - 0.009" guitar wire. There might be such wire around, but I haven't found it yet. :) I did get a bunch of assorted heat shrink sleeve a while ago to do another job so I might investigate the smallest size and see how small it gets when heated.

And I'm now beginning to question if the facility to change wire easily is really necessary - witness my recent exchange with Scott where we might decide on one wire gauge for our wagons and adjust the ballast on a wagon to suit. My original work on the "W" iron etch was done a couple of years ago when building the four wheel coaches and I think ideas change when you re-consider your original parameters. :)

Jim.
 

SimonT

Western Thunderer
Jim,
thank you. I am thinking of putting a small fold out tab towards the centre of one of the cross members. It will have a hole etched into to it to take the end of the spring. Thread the L shaped spring though the mounting/pivot holes and then with a small pair of pliers at either end, flex the end of the spring into the hole in the tab. Alternatively make the hole in the tab a small notch into which the end of the spring can be lowered. If it is on top, gravity should keep the spring in the notch.

And yes, I too look back on old designs in my work and wonder what was I thinking!

Simon
 

Dog Star

Western Thunderer
Jim, Simon,

I have read the recent posts and I am puzzled by your experiences with the Exactoscale sprung axleguard product. The original design by the (late) Bernard Weller was etched in brass, material thickness was (in my opinion) too thin and with the spring wire clamped/soldered to the top of the cradle. The revised design by Len Newman is etched in nickel silver, of thicker metal to minimise flexing and the spring wire contained within a pocket formed by folding the top of the cradle through 180 degrees. Len''s design has the spring wire free-floating and removable so that the spring thickness can be changed easily.

Which design are you discussing?

regards, Graham
 

Overseer

Western Thunderer
The current Exactoscale W irons are very clever and very different to the original ones. I have 4 wagons at varying states of completion using the current ones - they are much easier to set up. They haven't had much testing yet but seem to work well.

With the older type soldering the spring to the slider completely changes the spring action so thinner wire would be needed to get a similar amount of deflection, but thinner spring wire is more prone to sagging over time.
 

SimonT

Western Thunderer
Graham,
I fought one of Bernards etch for a long time and then consigned it to the bin. Len's design is a vast improvement and I have around 28 sets of them on the layout. Changing springs can be a complete pain and at other times the old spring comes out first time. The springs are all cut to length in a simple jig yet occasionally I get one that won't spring; goodness knows why. I find the carriers can be 'delicate' in setting up, with a tendency to jump off the pivot and move inboard. The W-irons can be easy to splay and this encourages the carrier to move from it's normal position. I would prefer to have a design where the carrier slides in rather than having to splay the W-iron to get the carriers and wheelset in.
As I need the correct heavy duty w-irons for both the 21 tonners and the various coils that are planned, I am taking the chance to learn from my experiences and to improve the design. In the heat of an exhibition it is very easy for a wagon to placed on the track a little heavily and for the carrier to jump out. Cue layout owner faffing about to fix a wagon.

And yes, I would still recommend Len's design but would caveat the recommendation with some advice.

All the best

Simon
 

JimG

Western Thunderer
Which design are you discussing?

Graham,

In my case most of my experience was with the original Bernard Weller 7mm scale "W" irons and I modified them to get away from clamping the spring wire in the bearing carrier. I'm now back in S scale and we have had some re-scaling from 4mm products - mainly Bill Bedford ones - and I didn't really like those designs. I think we got Len Newman to do a test scaling of one of his 4mm scale sprung underframes but I haven't had a chance to see that to assess how well it worked.

Like Simon, I needed specific axleguards - to suit pre-Group Scottish stock - and there are none available in S scale so I am having to draw up my own artwork and incorporate a springing system. The one I've developed does work well although I haven't had a chance to test it to destruction on something like a busy three day stint on an exhibition layout. :) My main reservation at the moment is fitting the bearing carriers when using large diameter coach wheels where locating the spring is not straightforward. My further modifications might well get round that problem, and I'll wait and see what Simon comes up with to see if he has got a better solution.

Jim.
 

SimonT

Western Thunderer
Jim,
photograph of the trial. The spring pivot points are 28mm apart and the spring retention point is 11mm from the bend. The wire is 28swg spring steel and protrudes .5mm ish beyond the far face of the retainer. It bent in very easily and finer spring wire was very easy to put in with tweezers. I am going to put a fold out tab, with a hole for the spring to go through on the carrier. This should allow the spring to keep the carrier aligned with the w-iron.

I'll post a drawing in due course if you are interested and you can have a copy of the file, to adjust for S Scale, if it is of any use to you.

All the best

Simon
132.JPG
 

JimG

Western Thunderer
Jim,
photograph of the trial. The spring pivot points are 28mm apart and the spring retention point is 11mm from the bend. The wire is 28swg spring steel and protrudes .5mm ish beyond the far face of the retainer. It bent in very easily and finer spring wire was very easy to put in with tweezers. I am going to put a fold out tab, with a hole for the spring to go through on the carrier. This should allow the spring to keep the carrier aligned with the w-iron.

I'll post a drawing in due course if you are interested and you can have a copy of the file, to adjust for S Scale, if it is of any use to you.

Simon,

I've actually been thinking down the same road but with a slightly different way of locking the end of the spring. I'll try and mock it up in the next hour to show you.

And a copy of your drawing file would be nice.

Jim.
 

JimG

Western Thunderer
Simon,

Here's my effort based on your earlier suggestions. Excuse the slightly ropey piercing saw cuts - trying to do the job too quickly. :)

axleguards-10.jpg

The central fulcrum has a notch at the inner end to house the spring wire and keep it close to the "W" iron frame. the central tab could have a notch as well - slightly out from the frame edge to bias the operational end of the spring to stay in its holes.

axleguards-11.jpg

axleguards-12.jpg

Another couple of pictures from different angles. I hadn't quite cut the notch in the fulcrum wide enough with the 6/0 saw blade so I bent the fulcrum tab down a tad to bias the spring towards the base.

I've been a bit generous with the length of the tabs and they could be quite a bit shorter.

I thought I'd go for this method over your hole in a tab method as I thought it might be a bit easier fitting or removing springs, and I could apply a bit of bias against the spring working its way out of the hole at its other end. However I should try the "hole" method to see if it is more difficult to fit and remove springs. :)

Onwards and upwards. :) I've got rid of that outrigger stop. :)

Jim.
 

SimonT

Western Thunderer
Jim,
exactly what I was thinking and tidier than my scruffy bend up piece of etch waste;).

However, a new idea. If instead of a tab there is a a slot in side rail of the base into which a separate etched tab goes; this tab could be used in two places. Once on to the base to hold the spring and once on the carrier to keep the carrier on the spring. The carrier tab could be soldered on earlier and dressed/polished flat. The base tab is placed on after the spring has been threaded through the base - carrier - base and is held by a dab of solder. The tab could double as the brake swing arms. I'll try to get it drawn up today.

Simon
 

JimG

Western Thunderer
However, a new idea. If instead of a tab there is a a slot in side rail of the base into which a separate etched tab goes; this tab could be used in two places. Once on to the base to hold the spring and once on the carrier to keep the carrier on the spring. The carrier tab could be soldered on earlier and dressed/polished flat. The base tab is placed on after the spring has been threaded through the base - carrier - base and is held by a dab of solder. The tab could double as the brake swing arms. I'll try to get it drawn up today.

Simon,

I will await your drawing. I'm supposed to be editing the December issue of the S Scale Gazette this week, so I don't really have enough time to do other things until I've got that finished. But I am very happy with what I think is a big improvement on the spring holding so thanks for getting me to think again. :)

Jim.
 

SimonT

Western Thunderer
Jim,
.pdf of my thoughts so far. You can see the base unit that includes the W-irons, a carrier on each side and one of the brake hanger units that also retains the spring. The spring and bearing are both missing. There would be a simple spring carrier etch for where no brake hanger is needed. When the etch drawing is complete I'll PM you a copy in .dxf format.

Hopefully you will be able to enter the pdf and manipulate the view as you can in Acrobat/Reader. Mods, if this file causes problems, I would be grateful for advice on how to place 3D .pdfs into WT.

All the best

Simon
 

Attachments

  • Heavy Duty W-Iron 3D.pdf
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JimG

Western Thunderer
Jim,
.pdf of my thoughts so far. You can see the base unit that includes the W-irons, a carrier on each side and one of the brake hanger units that also retains the spring. The spring and bearing are both missing. There would be a simple spring carrier etch for where no brake hanger is needed. When the etch drawing is complete I'll PM you a copy in .dxf format.

Simon

I won't be going down the road of adding brake assemblies. A lot of pre-grouping Scottish wagons had one lever and one brake shoe pivoted from the solebar. :) However I am thinking of another mod to the spring mounting - primarily to make assembly easier, especially with larger diameter wheels. The change would be to change the spring hole at the clamping end to be a vertical slot. I envisage the assembly starting with the axle and bearing carriers being inserted in their positions in the "W" irons. The one end of the spring wire be entered in the hole at the opposite side to the clamping side , "wiggle" (technical term :) ) the angle end of the spring to get the wire above the tab on the bearing carrier, then drop the wire in the slot and set the angled part under the tabs.

When I get some time away from the Gazette, I can modify the "W" iron setup I've messed about with already and see if it does make fitting the spring easier. One thing I can see is a possible difficulty in threading the wire through the hole from the inside of the frame - i.e. not being able to see what you are doing because of a coach wheel in the way. But it might be possible to thread the whole spring wire through the hole from the outside of the frame. Or I could look at making the hole larger and of a triangular shape to make threading the wire through from the inside a bit easier.

Hopefully you will be able to enter the pdf and manipulate the view as you can in Acrobat/Reader. Mods, if this file causes problems, I would be grateful for advice on how to place 3D .pdfs into WT.

I'm using Foxit for PDFs at the moment on this PC so can't do the 3D rotation bit, but I could see exactly what you are doing with the drawing as it displayed.

Jim.
 
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