Wagon springing and compensation - Newbie questions

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junctionmad

Wagon springing and compensation - Newbie questions

Postby junctionmad » Wed Mar 09, 2016 9:44 pm

Sorry about this but Im new to p4 and am doing my first scratch built wagons that will either be sprung or compensated

questions

1. With compensated W irons, these rock, so how are the springs and axleboxs attached, I presume a gap is left and the springs and boxes are attached to the W iron ??, or are people slotting the axle box and fixing it and the spring to the sole bars

2. in sprung wagons that have roller bearings, I can't see room to slot the axle boxes , what are people doing ?

apologies if there are threads on this , I searched and havent found this


thanks for your patience

Mark Forrest
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Re: Wagon springing and compensation - Newbie questions

Postby Mark Forrest » Wed Mar 09, 2016 9:49 pm

Which roller bearings are you using on your sprung wagons? Are you using normal or waisted pinpoint bearings in the spring carriers?

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James Wells
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Re: Wagon springing and compensation - Newbie questions

Postby James Wells » Wed Mar 09, 2016 10:07 pm

Mark Forrest wrote:Which roller bearings are you using on your sprung wagons? Are you using normal or waisted pinpoint bearings in the spring carriers?


I think he means the prototype has roller bearings - castings for these have much less metal in them. I'm building a couple of BR brake vans which use MJT roller bearings, I have slotted them, with care it's quite straight forward, the margin for error is just a little smaller.

junctionmad

Re: Wagon springing and compensation - Newbie questions

Postby junctionmad » Wed Mar 09, 2016 10:11 pm

James Wells wrote:
Mark Forrest wrote:Which roller bearings are you using on your sprung wagons? Are you using normal or waisted pinpoint bearings in the spring carriers?


I think he means the prototype has roller bearings - castings for these have much less metal in them. I'm building a couple of BR brake vans which use MJT roller bearings, I have slotted them, with care it's quite straight forward, the margin for error is just a little smaller.



yes , so I was looking at compensation W irons, but how do people fix the springs and axle boxes in this case

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Will L
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Re: Wagon springing and compensation - Newbie questions

Postby Will L » Wed Mar 09, 2016 10:14 pm

junctionmad wrote:S...1. With compensated W irons, these rock, so how are the springs and axleboxs attached, I presume a gap is left and the springs and boxes are attached to the W iron ??, or are people slotting the axle box and fixing it and the spring to the sole bars ..


Some people have a gap between the spring and the axle box, some have the gap between the spring and the sole bar. This is with traditional leaf springs, what could happen with a more modem wagon I am not competent to say.

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James Wells
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Re: Wagon springing and compensation - Newbie questions

Postby James Wells » Wed Mar 09, 2016 10:44 pm

With more modern pedestal suspension, I think sprung suspenion is a lot easier than rocking w-irons.

junctionmad

Re: Wagon springing and compensation - Newbie questions

Postby junctionmad » Wed Mar 09, 2016 10:47 pm

Will L wrote:
junctionmad wrote:S...1. With compensated W irons, these rock, so how are the springs and axleboxs attached, I presume a gap is left and the springs and boxes are attached to the W iron ??, or are people slotting the axle box and fixing it and the spring to the sole bars ..


Some people have a gap between the spring and the axle box, some have the gap between the spring and the sole bar. This is with traditional leaf springs, what could happen with a more modem wagon I am not competent to say.



Thanks, but to have a gap between the spring and the axle box with a rocking W iron , it means the spring is attached to the chassis via a very flimsy link , i.e. the real life spring holders, which in 4mm provide very little glueing/soldering surface ?

junctionmad

Re: Wagon springing and compensation - Newbie questions

Postby junctionmad » Wed Mar 09, 2016 10:49 pm

James Wells wrote:With more modern pedestal suspension, I think sprung suspenion is a lot easier than rocking w-irons.



I agree, how ever I have a number of rocking W iron etches , so was wondering the best way to either fix the springs and the box to the W iron and leave the " rocking " gap at the sole bar, or to fix the spring to the chassis and attach the axles box to the rocking w-iron

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grovenor-2685
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Re: Wagon springing and compensation - Newbie questions

Postby grovenor-2685 » Wed Mar 09, 2016 10:58 pm

In general I think springs are easier and work better in general.
Once upon a time rocking W-irons were the thing, but now we are spoilt for choice with springing systems.
If new to P4 its worth reading the P4 Manual and the original articles from the MRN and MRC.
See for example http://www.scalefour.org/history/p4rscomponents.html

Your last response came in while I was writing this, I have always fitted the axlebox and spring to the W-iron with a gap at the solebar. I thought the alternative was more work and more fragile.
Don't use waisted bearings for these, its best to keep the full fat 2mm bearing as it makes a good peg to hold the axlebox in place.
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Keith
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Will L
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Re: Wagon springing and compensation - Newbie questions

Postby Will L » Wed Mar 09, 2016 11:07 pm

junctionmad wrote:
Will L wrote:..Some people have a gap between the spring and the axle box, some have the gap between the spring and the sole bar...



Thanks, but to have a gap between the spring and the axle box with a rocking W iron , it means the spring is attached to the chassis via a very flimsy link , i.e. the real life spring holders, which in 4mm provide very little glueing/soldering surface ?


Think your seeing problems that don't exist. Where this was a practical choice, it was never fragile enough to cause a problem.

Which way you go depends on what form the springs come in. If, as was often the case, you had to remove them from an integral W iron, it was usually easier to put the gap between the spring and the box. Also some wagon kits came cast with separate axle boxes and the springs attached to the sole bar. If you start with separate spring/axlebox casting, it was usually easier to put the gap between spring and sole bar.

Where you have a choice I would put the gap between sprig and axlebox because it looks better, as with care you can hide most of the gap. However you don't always get the choice.

junctionmad

Re: Wagon springing and compensation - Newbie questions

Postby junctionmad » Thu Mar 10, 2016 1:16 am

Thanks everyone, I'll try some springing systems next

junctionmad

Re: Wagon springing and compensation - Newbie questions

Postby junctionmad » Thu Mar 10, 2016 7:28 am

James Wells wrote:
Mark Forrest wrote:Which roller bearings are you using on your sprung wagons? Are you using normal or waisted pinpoint bearings in the spring carriers?


I think he means the prototype has roller bearings - castings for these have much less metal in them. I'm building a couple of BR brake vans which use MJT roller bearings, I have slotted them, with care it's quite straight forward, the margin for error is just a little smaller.


Hmm , looking at mine , I see so little vertical space in the axle box casting , I think I'll fix the box to the hornblock and allow it to float with the springing unit, rather like when using compensation

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David B
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Re: Wagon springing and compensation - Newbie questions

Postby David B » Thu Mar 10, 2016 8:48 am

Can anyone suggest why the axlebox shouldn't be attached to the spring rather than the W iron? I doubt the gap behind the axlebox, once adjusted, should be very noticeable once painted and dirtied.

The first post in this thread asked about slotting the axle boxes. There is room to make a groove to allow the bit of the bearing that protrudes to move. I posted about making the grooves here last November. Finding things on this Forum is not easy so it is often quicker to ask and rely on someone else's memory.

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jjnewitt
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Re: Wagon springing and compensation - Newbie questions

Postby jjnewitt » Thu Mar 10, 2016 10:02 am

David B wrote:Can anyone suggest why the axlebox shouldn't be attached to the spring rather than the W iron?

No reason what so ever why the axlebox can't be attached to the spring carrier and move like the prototype. I think it's the only really practical solution for roller bearings and sprung chassis and is what I've started doing with mine. Slotting them sounds like really hard work if at all feasable.

The following is of one of my Plate wagons. The Exactoscale parallel bearing has been extended with 1.5mm x 1mm tube to give something for the bearing casting to locate onto. No reason why you can't do the same thing for pinpoint bearings or indeed oil type axleboxes. You need to file down the top of the casting a little to allow for the vertical movement but you don't need much.

Roller Bearings Forum.JPG

Appologies for the poor quality of the photo but it was the best one I could find.

Justin

billbedford
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Re: Wagon springing and compensation - Newbie questions

Postby billbedford » Thu Mar 10, 2016 10:09 am

James Wells wrote:
Mark Forrest wrote:Which roller bearings are you using on your sprung wagons? Are you using normal or waisted pinpoint bearings in the spring carriers?


I think he means the prototype has roller bearings - castings for these have much less metal in them. I'm building a couple of BR brake vans which use MJT roller bearings, I have slotted them, with care it's quite straight forward, the margin for error is just a little smaller.


You can always fix the axlebox to the bearing, but you will have to leave a small gap between the axlebox and the cosmetic spring.
Bill Bedford
Mousa Models
http://www.mousa.biz

junctionmad

Re: Wagon springing and compensation - Newbie questions

Postby junctionmad » Thu Mar 10, 2016 10:13 am

David B wrote:Can anyone suggest why the axlebox shouldn't be attached to the spring rather than the W iron? I doubt the gap behind the axlebox, once adjusted, should be very noticeable once painted and dirtied.

The first post in this thread asked about slotting the axle boxes. There is room to make a groove to allow the bit of the bearing that protrudes to move. I posted about making the grooves here last November. Finding things on this Forum is not easy so it is often quicker to ask and rely on someone else's memory.



As I see it there are these options

For compensation style rocking W-irons

1. fix the spring to the solebar and attach the axle box to the rocking W-iron, gap between axle box and spring
2. fix both spring and axle box to the rocking W-iron and gap is between spring brackets on solebar and spring
3. Fix both to solebar and slot the axle box

for spring based W-irons

1. Attach the spring & axle box to the W-iron/solebar, and slot the axle box
2. attach the spring to the W-iron/solebar and separately fix the axlebox to the "horn block", gap is then between axle box and spring

personally for roller bearing box representations, I favour the second #2 as I find it difficult to find the space in the casting for the slot for the bearing, for oil axle boxes there its typically enough space


No reason what so ever why the axlebox can't be attached to the spring carrier and move like the prototype. I think it's the only really practical solution for roller bearings and sprung chassis and is what I've started doing with mine. Slotting them sounds like really hard work if at all feasable.


+1

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James Wells
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Re: Wagon springing and compensation - Newbie questions

Postby James Wells » Thu Mar 10, 2016 8:21 pm

billbedford wrote:You can always fix the axlebox to the bearing, but you will have to leave a small gap between the axlebox and the cosmetic spring.


I have done that in the past with oil axleboxes but with the roller bearings, seeing the hornguides moving up and down with the axle box, might look a bit odd!

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grovenor-2685
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Re: Wagon springing and compensation - Newbie questions

Postby grovenor-2685 » Thu Mar 10, 2016 9:16 pm

Which bit do you mean by 'Hornguide' ?
The cast housing which holds the roller bearing moves up and down in the slot in the W-iron just as a plain bearing axlebox does.
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Keith
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James Wells
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Re: Wagon springing and compensation - Newbie questions

Postby James Wells » Thu Mar 10, 2016 9:18 pm

I must be showing my ignorance of wagons - my background is p-way and I spend my time pulling levers and ringing bells now!

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David B
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Re: Wagon springing and compensation - Newbie questions

Postby David B » Thu Mar 10, 2016 10:01 pm

I am getting confused with the vocabulary here.

'Roller bearings' - are these what we know as pinpoint and plain bearings? I always thought 'roller bearings' had small rollers in a casing, like ball bearings.

I thought hornguides are on locos. On the model wagons (and coaches), I think you are referring to the bearing carriers.
Last edited by David B on Thu Mar 10, 2016 10:41 pm, edited 1 time in total.

Mark Forrest
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Re: Wagon springing and compensation - Newbie questions

Postby Mark Forrest » Thu Mar 10, 2016 10:06 pm

billbedford wrote:
James Wells wrote:
Mark Forrest wrote:Which roller bearings are you using on your sprung wagons? Are you using normal or waisted pinpoint bearings in the spring carriers?


I think he means the prototype has roller bearings - castings for these have much less metal in them. I'm building a couple of BR brake vans which use MJT roller bearings, I have slotted them, with care it's quite straight forward, the margin for error is just a little smaller.


You can always fix the axlebox to the bearing, but you will have to leave a small gap between the axlebox and the cosmetic spring.

The brown VDA below has the axlebox fixed to the pinpoint bearing so it moves up and down with the suspension, the red/grey VDA has the axlebox (these being plastic ones from Chivers) opened up to allow movement of the waisted pinponit bearing behind it.
25656404936_1c838a70fb_o.jpg

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grovenor-2685
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Re: Wagon springing and compensation - Newbie questions

Postby grovenor-2685 » Thu Mar 10, 2016 11:00 pm

David B wrote:I am getting confused with the vocabulary here.

Watch out for prototype vv model terminology.
'Roller bearings' - are these what we know as pinpoint and plain bearings? I always thought 'roller bearings' had small rollers in a casing, like ball bearings.

The prototype may have roller bearings, as you describe them (and as on the VDAs above) or plain bearings inside an axlebox.
On our models these parts are normally cosmetic castings and the actual pinpoint or plain bearings are hidden behind
I thought hornguides are on locos. On the model wagons (and coaches), I think you are referring to the bearing carriers.

I understand hornguides as the two bearing surfaces either side of the axleboxes on steam locos, these have to take all the traction forces, piston thrusts etc. and are substantial, 6 inches or more wide. The axleboxes on wagons are located under the springs and there is normally some clearance between the sides of the box and the W-irons contact only being made from shocks or when the brakes are applied. The edges of the W-iron slots sometimes have reinforcing strips to take wear, particularly on vac or air brake stock.
The reference to bearing carriers above meant the etced frames linking the model bearings to the guitar wire springs, hidden on the model as they don't exist on the real thing.
Regards
Regards
Keith
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junctionmad

Re: Wagon springing and compensation - Newbie questions

Postby junctionmad » Fri Mar 11, 2016 2:06 am

Just to clarify

Roller bearings , refer to modern ( ie post war ) axle boxes on the prototypes as opposed to traditional oil axle boxes. There's no equivalent in modelling. Our model bearings are either pinpoint or parallel bushed bearings

A horn block ( I'm not sure it's correct to say horn guide, I don't think it's a word ) is any specific bearing surface that prevents horizontal ( lateral ) movement of an axlebox. It's usually a wear item and is replaceable. They can be on locos , carriages or wagons. Typically in modern roller bearing axleboxex there are horn blocks that provide a bearing surface for the axle box , the horn block taking the lateral forces but allowing vertical spring related movement.

I beleive the term hornblock , is used incorrectly in model loco terminology as a synonym for bearing carrier.

" block" in horn block being the same idea as brake " block " , the block being a bearing surface

In the real life , only the roller bearing moves the horn blocks obviously do not , but in 4mm the horn block and roller axlebox tend to be cast together.

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David B
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Re: Wagon springing and compensation - Newbie questions

Postby David B » Fri Mar 11, 2016 8:22 am

Thank you for the clarifications. I was getting confused between the real thing and models. As the latter appear to be modern stock, something I know nothing about (not my scene), I will quietly retreat.


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