Loco Suspension, fitting CSBs

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LesGros
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Re: Pick-ups for the J10 part 2

Postby LesGros » Fri Jan 18, 2013 2:36 pm

Will L" wrote:
Matters arising
In writing the material that appears as part 1, I found that I was including a lot of material which related to my rationale for doing what I did. The result was long, even by my standards. As I wanted there to be at least a fighting chance that some people would read to the end, I extracted a lot of the rationale stuff. This omission is already leading to comments. It is given here now, along with details of another application and, in the spirit of the best day time reality TV shows, ultimately, what happens under the J10 loco... ... ...

Will,
Thank you for posting such a useful summary. :thumb
LesG

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never made anything useful

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Andy W
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Re: Loco Suspension, fitting CSBs

Postby Andy W » Fri Jan 18, 2013 5:29 pm

Will, as a supporter of split axles I have to say that all looks splendid. You could even tempt me back to wipers - but not just yet. One rather inane question - why do you wind the pick up PB wire so that the natural spring bends away from the contact? Is that to soften the friction? If they were wound the other way wouldn't it help to maintain the connection? I'm not criticising - just curious.
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Will L
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Re: Loco Suspension, fitting CSBs

Postby Will L » Fri Jan 18, 2013 7:09 pm

Ealing wrote:Will, as a supporter of split axles I have to say that all looks splendid. You could even tempt me back to wipers - but not just yet. One rather inane question - why do you wind the pick up PB wire so that the natural spring bends away from the contact? Is that to soften the friction? If they were wound the other way wouldn't it help to maintain the connection? I'm not criticising - just curious.


Curiosity is perfect acceptable, it's what drive me too. I think if you look carefully you'll see I've done it both ways, and I'm not sure I've noticed a significant difference, but as measuring the tip pressure on the wipers is a might tricky it's hard to tell. You may or may not be right.

Actually because they are handed I get enough problems making them all the same way to worry too much about which way. Other users may care to comment

Will

billbedford
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Re: Loco Suspension, fitting CSBs

Postby billbedford » Sat Jan 19, 2013 10:29 am

Russ Elliott wrote:
billbedford wrote:If you are going to use pickup like that why bother with CSBs?

Because of the difference desired between the vertical force in the beam and the vertical force in the pickup. The beam force might be in the region of say 20 to 30g on the axlebox, but the pickup force will be, hopefully, at least an order of magnitude lower.

Hopefully? Well I suppose that will depend on whether cooker wire is used for the pickups.

If the pickup force were of a magnitude similar to that of the beam, the wheel wouldn't turn because the braking force on the wheel would be comparable to the frictional force (i.e., in the case of locos, the potential tractive force) at the railhead.


But Russ, I know you know that this isn't true because you watched a loco with just this suspension arrangement doing it's stuff last Friday.
Bill Bedford
Mousa Models
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David Thorpe
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Re: Loco Suspension, fitting CSBs

Postby David Thorpe » Sat Jan 19, 2013 5:42 pm

Getting back to Will's tender, I'd be very pleased to know the best way of taking the current from the tender to the loco while at the same time ensuring that the two can be parted when necessary without too much difficulty. My efforts at doing this have usually ended up with an unsightly jumble of unruly wiring. If you could go on to cover that aspect while dealing with this topic I'd be very grateful.

DT

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Russ Elliott
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Re: Loco Suspension, fitting CSBs

Postby Russ Elliott » Sat Jan 19, 2013 9:11 pm

billbedford wrote:Hopefully? Well I suppose that will depend on whether cooker wire is used for the pickups.

I must admit to being a bit surprised at Will using a diameter as thick as 0.35mm, but the strength of the spring contact is determined primarily by the number of coils (hence length) he uses, and Will confirms his overall 'pickup loss' is in the region of 10% of the tender weight. Which seems eminently reasonable. (Actually, I wrote my post before seeing Will's, so it was good to see the hopefully 'order of magnitude' being attained in practice.)

But Russ, I know you know that this isn't true because you watched a loco with just this suspension arrangement doing it's stuff last Friday.

I think you will find that loco is predominantly 'spring-assisted', so isn't the same suspension arrangement being addressed in this thread. (That loco has 9mm long 0.008" cantilevers. Notwithstanding the considerable preload, at approx 0.07N/mm, those cantilevers are in the region of an order of magnitude weaker than most 4mm CSB loco driver springs.)

And none of that detracts from me being impressed by the loco 'doing its stuff'.

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Will L
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Re: Loco Suspension, fitting CSBs

Postby Will L » Sun Jan 20, 2013 10:28 pm

Russ Elliott wrote:I must admit to being a bit surprised at Will using a diameter as thick as 0.35mm


Its what I had to hand really Russ, but I think the result have proved entirely practical trade off between reasonable robustness and a light enough touch. I've tried 36 swg (0.19mm) but that is just too unruly and hard to manage, and it gets pulled out of shape much to easily. I have used it under the Y5 when the pick-ups are inevitably quite short and they have been a pain.

Will

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David Thorpe
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Re: Loco Suspension, fitting CSBs

Postby David Thorpe » Mon Jan 28, 2013 9:18 am

Having been much impressed by your tender pickup arrangement, Will, I thought I'd try it out together with CSBs on an old tender chassis that had been pretty unsatisfactory. So I took it to bits and rebuilt it and the result is pictured below. Not as neat as yours, I'm afraid, but I'm quite pleased with it as a first effort. Making the springs was much easier than fitting them! FWIW, I used 0.7mm brass wire for the bus bars and 31 swg PB wire for the springs. The tube used to fit the springs was some stainless steel stuff that I happened to have handy, OD 1.6mm. For the CSBs I used modified MJT hornguides and blocks together with Markits handrail knobs.

Now I've got to find a way of transferring the current to the loco that doesn't involve an awful and unsightly jumble of wires.

tender1.jpg
tender1.jpg (191.34 KiB) Viewed 6343 times

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Mike Garwood
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Re: Loco Suspension, fitting CSBs

Postby Mike Garwood » Mon Jan 28, 2013 10:32 am

You might find these useful, given their size.

http://www.micronradiocontrol.co.uk/conn_pwr.html

Mike

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David Thorpe
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Re: Loco Suspension, fitting CSBs

Postby David Thorpe » Mon Jan 28, 2013 12:37 pm

Thanks, Mike. I've also seen these:
http://www.expressmodels.co.uk/acatalog ... ctors.html

DT

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Mike Garwood
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Re: Loco Suspension, fitting CSBs

Postby Mike Garwood » Mon Jan 28, 2013 3:41 pm

With the Micron models versions being only 0.8mm I was thinking that the wires could be mounted either side of the tender to simulate the water pipes running from the tender. At least that's what I'm going to try on the Hawksworth tender I have. Might be that the wiring will be too stiff to allow the tender to move freely. Not exactly going to break the bank if I'm wrong.

cheers

Mike

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David B
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Re: Loco Suspension, fitting CSBs

Postby David B » Mon Jan 28, 2013 3:54 pm

There were often small buffers between tender and loco. How about representing them with the plunger type of pick-up?

David

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Tim V
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Re: Loco Suspension, fitting CSBs

Postby Tim V » Mon Jan 28, 2013 4:45 pm

davidb wrote:There were often small buffers between tender and loco. How about representing them with the plunger type of pick-up?

David

So how does the water get from engine to tender? How does the vacuum/air pipe get from engine to tender? How about the steam heat (if fitted)? All these things can be represented by wires between engine and tender.
Tim V

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David B
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Re: Loco Suspension, fitting CSBs

Postby David B » Mon Jan 28, 2013 4:52 pm

Tim V wrote:So how does the water get from engine to tender? How does the vacuum/air pipe get from engine to tender? How about the steam heat (if fitted)? All these things can be represented by wires between engine and tender.


Indeed they can, Tim. I wasn't suggesting otherwise.

I was referring to DaveyTee's post and perhaps should have quoted him:

DaveyTee wrote:Now I've got to find a way of transferring the current to the loco that doesn't involve an awful and unsightly jumble of wires.


I was suggesting a solution which might solve this (particular feature) quite neatly.

David

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David Thorpe
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Re: Loco Suspension, fitting CSBs

Postby David Thorpe » Mon Jan 28, 2013 5:54 pm

Mike Garwood wrote:Not exactly going to break the bank if I'm wrong.


They do look very useful. Pity about the minimum postage charge of £5 however.

David's plunger pickup idea is ingenious - if I had any I'd be sorely tempted (thinks ruefully of the plunger pickups thrown away as useless in the past)

DT

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Mike Garwood
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Re: Loco Suspension, fitting CSBs

Postby Mike Garwood » Mon Jan 28, 2013 6:51 pm

DaveyTee wrote:
Mike Garwood wrote:Not exactly going to break the bank if I'm wrong.


They do look very useful. Pity about the minimum postage charge of £5 however.
DT


AHHHHH, hadn't spotted that...blast.

Mike

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Flymo748
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Re: Loco Suspension, fitting CSBs

Postby Flymo748 » Mon Jan 28, 2013 7:06 pm

DaveyTee wrote:David's plunger pickup idea is ingenious - if I had any I'd be sorely tempted (thinks ruefully of the plunger pickups thrown away as useless in the past)

DT

If you want some, I'll send you plenty!

My view is that they are so terrible as pickups that I won't even punt them off on the unsuspecting via Ebay...

Flymo
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Tim V
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Re: Loco Suspension, fitting CSBs

Postby Tim V » Mon Jan 28, 2013 7:26 pm

I use these plugs http://www.maplin.co.uk/2.54mm-0.1in.-pin-strip-1500
Used to be some sockets, but I can't see them in the current catalogue.
Tim V

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David B
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Re: Loco Suspension, fitting CSBs

Postby David B » Mon Jan 28, 2013 10:58 pm

Flymo748 wrote:
My view is that they are so terrible as pickups that I won't even punt them off on the unsuspecting via Ebay...

Flymo


I can see they might not be as good on the revolving tyre, picking up dirt which could then break the contact, but on a relatively static place like the footplate / tender join, a plunger on one side and a plate on the other ought to be better. It would also be easier to get a bit of wet & dry in there to give them a tickle from time to time.

If I had a tender loco to try them on, I would give it a go, if only to prove their usefulness or lack of it. Unfortunately, I don't.

David

billbedford
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Re: Loco Suspension, fitting CSBs

Postby billbedford » Tue Jan 29, 2013 9:44 am

Flymo748 wrote:My view is that they are so terrible as pickups that I won't even punt them off on the unsuspecting via Ebay...


The trick is not to use cooker wire to connect the pick ups to the motor. Use as fine a wire as you can and coil it.
Bill Bedford
Mousa Models
http://www.mousa.biz

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Will L
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Re: Loco Suspension, fitting CSBs

Postby Will L » Tue Jan 29, 2013 4:39 pm

DaveyTee wrote:.. I thought I'd try it out together with CSBs on an old tender chassis that had been pretty unsatisfactory. So I took it to bits and rebuilt it and the result is pictured below. Not as neat as yours, I'm afraid, but I'm quite pleased with it as a first effort.


That looks like a nice workman like job.

DaveyTee wrote:Now I've got to find a way of transferring the current to the loco that doesn't involve an awful and unsightly jumble of wires.


These are the two pin plugs and sockets I use. I got these, at 95p a go, from All Components Ltd. They attend some shows, I see them at Manchester. They also stock the 0.7mm multi-strand insulated wire I use on my loco’s which is also in the picture. This is fine enough not to qualify as cooker wire, whatever that is.
CSB J10T 20 plugs.jpg

I haven’t quite got round to electrically connecting the J10 tender and loco yet but this picture shows all the bits, all that remains to be done it to wire up the plug and socket.
CSB J10T 19 fullset.jpg

The centre section, which I haven’t introduced you to before, is an extension of the bus bars on the loco pick-ups. It carries them round the gearbox and rear axle, and terminates them under the loco draw bar, where the connections for the water pipes from the tender should be. This centre section uses a second PCB pad which is held in place under the draw bar by the bolt that joins the chassis and body. Note the use of tube to make simple plug and socket joints in the bus bar. This works fine so long as you remember to put a modicum of curve on the bit of wire that fits down the tube. I’ve used a variant of this approach to join loco to tender in the past but in the end its simpler to use the cheap plug and socket.

Here they are all installed on the chassis.
CSB J10T 21 installed.jpg


davidb wrote:There were often small buffers between tender and loco. How about representing them with the plunger type of pick-up?


Interesting idea, but I’m not sure I fancy it. Could you actually get sufficient free movement between loco and tender? Sounds like a recipe for unexplained derailments to me.

Will

Chris Mitton
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Re: Loco Suspension, fitting CSBs

Postby Chris Mitton » Tue Jan 29, 2013 7:43 pm

billbedford wrote: Use as fine a wire as you can and coil it.


Not that I'm an expert on these things, I suspect Bill's advice is mechanically sound, but if using DCC, ie alternating current from the wheels through the pickups to the decoder chip, won't coiling them turn the pickups into induction coils and generate strange and unhelpful back-emf? Or is this a non-problem?

How fine is "as fine as" that will still carry the requisite current?

Regards
Chris

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Horsetan
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A dissenter: Re: Loco Suspension, fitting CSBs

Postby Horsetan » Thu Mar 31, 2016 10:01 am

That would be an ecumenical matter.

dal-t
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Re: Loco Suspension, fitting CSBs

Postby dal-t » Thu Mar 31, 2016 11:06 am

Ah, but they've not yet tried running it over scale RSGs across the lines, or hauling 'equal to 20' up a 1in6 gradient at 70mph, have they? Whoever heard of the idea that a model's tractive effort should be proportionate to that of the prototype, anyway? Without CSBs we wouldn't be able to watch a fully loaded mineral behind an asthmatic 1F nudging its own taillamp around a forty-foot test track, would we?
David L-T

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Will L
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Re: A dissenter: Re: Loco Suspension, fitting CSBs

Postby Will L » Thu Mar 31, 2016 5:01 pm

Horsetan wrote:Meanwhile, in another place, someone who thinks the whole CSB thing is overrated....


But then just look who it is.


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