Loco Suspension, fitting CSBs

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Flymo748
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Re: Wheels for the J10, part 2

Postby Flymo748 » Wed Feb 23, 2011 11:42 pm

Will L wrote:...The second is to have a sacrificial pair of wheels which you can assemble on the axle with the axle block and washers, repeatedly if necessary, so you can check it all goes in the frames with the required amount of free play. The sacrificial wheels have to be the same basic width as the real ones but need not be the same diameter. With Gibson wheels just make sure the raised hub at the back stands proud of the wheel rims by the same amount. Once you have one pair you can use them to make many chassis.


I wanted to say thanks very much for the tip! I've already had my Y14 wheels on and off the axles several times in the course of the build, so they are probably comprehensively "loosened" by now :-(

However I've used a spare set of Gibson wheels to set up the driving axle, trying a variety of washers to get to ones with minimal side play. And of course, with CSB suspension, I could do this out of the chassis just by pulling the wires forward and dropping the axleboxes out from underneath. As I ensured that the motor that I chose is narrow enough to go back in between the chassis sides, then re-installing it will be no problem either :-)

Here are a couple of pictures of the whole ensemble after it was assembled.

Slimliner 001.jpg


Slimliner 005.jpg


The trusty GW wheelpress was used for the quartering. When I've got the other two axles done, and it all back in the chassis, I'll see how competent I've been about it!

Cheers
Flymo
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Philip Hall
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Re: Loco Suspension, fitting CSBs

Postby Philip Hall » Thu Feb 24, 2011 1:58 pm

Another way to adjust sideplay is to use Peco fibre washers, with a small chunk cut out of them, to slip on and off the axle. Tim V put this on the Forum a while back now, but I can't remember where! I use brass washers to take up most of the sideplay but use a dummy axle, turned down to be a sliding fit on a wheel, to roughly work out the required number, then fine tune it once the job's properly assembled with the thin fibre ones. These can also be thinned down very easily. If you haven't got a lathe, a bit of rough filing on some 1/8" brass rod will do just as well.

Philip

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HowardGWR
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Re: Loco Suspension, fitting CSBs

Postby HowardGWR » Thu Feb 24, 2011 5:54 pm

Which gearbox is that Paul please?

I've got to ask this as well, why would anyone gratuitously call themselves flymo? :)

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Flymo748
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Re: Loco Suspension, fitting CSBs

Postby Flymo748 » Fri Feb 25, 2011 7:57 am

HowardGWR wrote:Which gearbox is that Paul please?


It's the HighLevel SlimLiner+ gearbox. I (hope that I have) attached a scan of the first page of the instructions so you can see the drivetrain layout. Of course, Chris also makes freely available a very useful sheet of all the gearboxes, their sizes and configurations on the High Level website.

HowardGWR wrote:I've got to ask this as well, why would anyone gratuitously call themselves flymo? :)


Well, I was explaining this to Jol from London Road only last Sunday, at the Watford show...

It goes back to one summer, about a dozen years ago. I'm part of a motorbike mailing list called Ixion (which was, coincidentally the same reason that I was chatting with Jol) and every year we privately hire Cadwell Park race circuit in Lincolnshire. It's our own private event, just us and invited friends, and we spend two days riding hard, or less hard, around in circles.

I was still to learn properly the hanging-off, knee-down style of riding quickly, and had repeated issues with riding off the edges of tyres when cornering. I'd crashed in the morning sessions, and been recovered back to the paddock. After replacing bent levers, footpegs, etc, I was back out again for the afternoon...

Where I promptly threw the bike into the scenery again, at the bottom of the Mountain. Once again, it was back to the paddock, but under my own steam, not in a recovery van. That area at the bottom of the Mountain had just been mown, and my bike (the same one that's in the avatar - I rather like that picture from Pembrey circuit) was stuffed with grass: behind the screen, inside the fairing, all over the place. I even removed a load from the airbox when I serviced it six months later.

As I rode into the paddock, one of my mates commented that I should be sponsored by Flymo. By the next morning, the name was in half a dozen emails talking about the day, and I've had it ever since :-)

It's remarkably useful, for at our social events we get several Pauls, but only one Flymo! I've also had it yelled at me across the floor of John Lewis in Bluewater and it gets my immediate attention. Even my wife uses it, generally in the race paddock. She passengers a Formula 2 Sidecar ( (http://www.lickracing.com) and it's very handy for her to be able to get my attention and no one else's. Her sidecar builder is also called Paul, but everyone calls him Herman!

So that's the story... The 748 is a reference to my premier road bike, even if it has now been re-engined with a rather special 916 lump :-)

Cheers
Flymo
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HowardGWR
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Re: Loco Suspension, fitting CSBs

Postby HowardGWR » Fri Feb 25, 2011 3:48 pm

Thanks Paul. I tried to come up with a suitable response but could only think of 'supergrass' which isn't very helpful.

The instructions for the High level gb are very comprehensive and I shall certainly look at the products for the next project. The varieties available are if anything too bewilderingly comprehensive so I think i will write to the owner and go by his suggestion.

Was there not a 'horizontal' position for the motor available? I don't know why one should worry about aesthetics when one can't see the thing anyway, but.....

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45609
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Re: Loco Suspension, fitting CSBs

Postby 45609 » Fri Feb 25, 2011 8:28 pm

Flymo748 wrote:So that's the story... The 748 is a reference to my premier road bike, even if it has now been re-engined with a rather special 916 lump :-)


Those capacities can only mean a particular brand of 2 wheeled Italian garage porn.....Ducati

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dcockling
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Re: Loco Suspension, fitting CSBs

Postby dcockling » Fri Feb 25, 2011 9:44 pm

mlgilbert30 wrote:
Flymo748 wrote:So that's the story... The 748 is a reference to my premier road bike, even if it has now been re-engined with a rather special 916 lump :-)


Those capacities can only mean a particular brand of 2 wheeled Italian garage porn.....Ducati


You've rumbled him Morgan :lol:

All the Best
Danny

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Flymo748
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Re: Loco Suspension, fitting CSBs

Postby Flymo748 » Fri Feb 25, 2011 10:16 pm

mlgilbert30 wrote:
Flymo748 wrote:So that's the story... The 748 is a reference to my premier road bike, even if it has now been re-engined with a rather special 916 lump :-)


Those capacities can only mean a particular brand of 2 wheeled Italian garage porn.....Ducati


<VBG> Amongst other things, yes... But those are the bikes that I'll keep.

After the 748 ate its crankshaft, due to a balls-up by a Ducati main dealer that blocked the oil passages, a certain drinking mate of mine on the Isle of Man found a 916 lump spare at Donington, threw a few parts that he had at the back of his workshop into it, and set it up rather nicely.

This is who did it... http://www.slickperformance.co.uk/10552.html. Bit of a pedigree :-)

I'm sure that it's not to everyone's taste, but I rather love it...

Flymo
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rule55
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Re: Loco Suspension, fitting CSBs

Postby rule55 » Sat Feb 26, 2011 7:50 am

Flymo748 wrote:
This is who did it... http://www.slickperformance.co.uk/10552.html. Bit of a pedigree :-)



Flymo


Bit of a pedigree? I should say!

Richard.Ough

Re: Loco Suspension, fitting CSBs

Postby Richard.Ough » Sun Feb 27, 2011 5:30 pm

Sorry guys,

We are drifting off the subject of CSBs here, Motorcycles are not my scene, but CSB in P4 are, can we get back on topic or start up another thread?

Again sorry.

Regards

Richard

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Flymo748
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Re: Loco Suspension, fitting CSBs

Postby Flymo748 » Sun Feb 27, 2011 9:59 pm

HowardGWR wrote:The instructions for the High level gb are very comprehensive and I shall certainly look at the products for the next project. The varieties available are if anything too bewilderingly comprehensive so I think i will write to the owner and go by his suggestion.


That's only the first page of the instructions... There's a second page as well.

They are not bewildering, but simply comprehensive. For example, much of that first page deals with how to use the gearbox with a remotely mounted motor and a UJ driveshaft. If you're not using one of these, then you can safely ignore large chunks of the text.

The gearbox itself all fits together so well that the instructions really could be written on the back of a fag packet. There are only two things to consider: all the etched holes are (deliberately, and properly) undersized for use, so ream them out carefully, frequently stopping and checking; and use the exploded diagram to get the gears in the correct orientation. The rest is simples!

HowardGWR wrote:Was there not a 'horizontal' position for the motor available? I don't know why one should worry about aesthetics when one can't see the thing anyway, but.....


It probably would have been possible, but then the motor would have been visible below what is a slim and quite high-pitched boiler. Okay, so I haven't built dummy inside valve gear, but not cluttering up that space with the motor was important enough to me to stand the motor up in the firebox.

Flymo
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Will L
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Re: Loco Suspension, fitting CSBs

Postby Will L » Tue Mar 08, 2011 12:16 pm

I have just returned from my holidays, and while I was away I came across an interesting class of steam loco still very much in action
Inda class X.jpg
Inda class X.jpg (159.06 KiB) Viewed 9536 times

I couldn't help wondering how A CSB plot for one of these would work out! To make it clear where the wheels are this is a picture of a member of the same class in the Delhi railway museum.
Inda class X old.jpg
Inda class X old.jpg (213.36 KiB) Viewed 9536 times

This particular one has been retired for some years. The one in the original photo has since been converted to oil firing, and has other interesting little mods, like the donkey engine installed in what used to be the coal bunker.

For those who want to know, this is a Swiss built Indian Railways class X meter gauge 0-8-2 ABT rack loco. A 4 cylinder compound, with the high pressure cylinders working the driving wheels and the low pressure cylinder driving the rack pinion. Built in 1898 to carry tea to the nearest railway and hence the coast, the Nilgiri Mountain Railway also made a good living transporting members of the Raj up to the hills station at Ooty (Or Udhagamandalam if you must be picky). Now like the Darjeeling railway one of India's "Toy Trains" and a world heritage site. They will hopefully be trundling up and down hill for a long time to come.

And yes I think I have a springy beam solution, but not a conventional or wholly continuous one. Any way I think making the low pressure valve gear look like it is doing something useful might be more of a challenge. Perhaps I need to go again and study the prototype in detail. The steam shed has a banner over the foot path entry that says "Welcome", and nobody bats an eyelid if you wonder in and have a look.

Will

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David Thorpe
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Re: Loco Suspension, fitting CSBs

Postby David Thorpe » Wed Nov 09, 2011 10:22 am

Having successfully equpped a tender with CSBs, and driven by the fervour of the Previously Sceptical But Now Converted, I've now taken to bits a previously poorly performing J15 chassis and am rebuilding it with CSBs and a High level gearbox. Fortunately I don't have to resort to spreadsheets or even paper and pencil as there's already a plot for this loco on the CLAG site.

Meanwhile, I was wondering if you've now finished with this thread, Will, as there hasn't been a posting on it for some six months or so?

DT

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Will L
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Re: Loco Suspension, fitting CSBs

Postby Will L » Wed Nov 09, 2011 4:48 pm

Well done Dave for progress made.

It is true I haven't posted here for a while but I have on CSBs and the Single Bogie, CSBs a question of Gravity, and significant chuncks of Abstruse CSB Theory in the mean time. I also got rather tied up with testing Alan's new spread sheet, preparing for the CSB workshops at Scaleforum, dealing with my fathers funeral and his estate, going on holiday (twice) and trying to finishing of a regrettably CSB free Y5. So basically a load of excuses for doing nothing really.

However I do intend to finish the J10 story in due course and that will generate posts here, though I'm not planning to make too much of it as the CSB element is now behind us. Then of courser there will be the interesting decision about which loco I'll start on next. Though which lifetime that will happen in I'm not sure.

In the mean time I shall be on the Society stand at Warley both days next week end so if anybody want to come by and talk suspensions...

Will

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David Thorpe
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Re: Loco Suspension, fitting CSBs

Postby David Thorpe » Wed Nov 09, 2011 5:48 pm

Will L wrote:I also got rather tied up with testing Alan's new spread sheet,

Thanks, Will. As to the spreadsheet, what is the current definitive version? I have discovered (and this is going to sound really stupid) that one of the reasons I haven't been able to work it is because, contrary to my belief at the time, I don't actually have Excel on my computer :oops: . My wife, on the other hand, does have it on hers, so I thought I might give it another go using her machine.

DT

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Russ Elliott
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Re: Loco Suspension, fitting CSBs

Postby Russ Elliott » Wed Nov 09, 2011 7:07 pm

All the current versions of the spreadsheets (Roger Wyatt's, Will's expanded version of it, and Alan Turner's) are downloadable from the CLAG CSB page. Although I haven't tried it myself, I think the free Open Office suite will be able to read the spreadsheets, so Microsoft Excel isn't really necessary.

Chris Mitton
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Re: Loco Suspension, fitting CSBs

Postby Chris Mitton » Wed Nov 09, 2011 8:07 pm

Russ Elliott wrote: Although I haven't tried it myself, I think the free Open Office suite will be able to read the spreadsheets, so Microsoft Excel isn't really necessary.


The spreadsheets do indeed work in Open Office, and from ten paces look just the same as in Excel. Open Office has the great advantage that you don't have to keep paying Bill Gates' crew squillions of pounds every couple of weeks to provide extra stuff you didn't want and make the things you do want work in annoyingly different ways.....

Some of the spreadsheets use macros to work, so unless you're less paranoid than me you may have to tweak your security settings in Open Office.

Regards
Chris

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David Thorpe
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Re: Loco Suspension, fitting CSBs

Postby David Thorpe » Mon Nov 28, 2011 9:45 pm

Well, I've come to an abrupt halt on my J15 basically because of the gearbox problems that have been referred to previously in this forum. I had hoped to use a Loadhauler+, which is 1mm narrower than the compact, but it still just falls foul of the Markit fulcrum points (and in any event is just too high to fit in the J15). The RoadRunner+ is 1mm narrower than the LoadHauler and might therefore fit, but I want an 80:1 gear ratio and the RoadRunner only goes up to 54:1. I read Will's explanation as to how to convert the LoadHauler Compact/D2 combination, but I'm afraid i didn't quite understand it fully though I suspect i wopuld have done had I had the components to hand. Similarly, I've read Flymo's post on the Slimliner, but I don't really like that because, again, it only goes up to a 54:1 ratio and I also much prefer the axle drive gear to be fixed by a grub screw, not adhesive as I'm bound to need to take it off again at least once during construction :( .

As things stand I'm going to have to get another gearbox in any event, so i have to decide whether to get the RoadRunner+ which I'm confident will fit and for which i already have a D1 Drivestretcher, but which doesn't have such a good gear ratio, or spend a bit more and get a LoadHaulerCompact and a D2 and hope that I can carry out the conversion suggested by Will. I've found the HighLevel gearboxes truly excellent so I do hope that Chris comes up with some new gearboxes that are rather more CSB friendly and have the final drive gear secured by a grub screw!

DT

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Will L
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Re: Loco Suspension, fitting CSBs

Postby Will L » Tue Nov 29, 2011 12:17 am

DaveyTee wrote:..or spend a bit more and get a LoadHaulerCompact and a D2 and hope that I can carry out the conversion suggested by Will.


Can I reassure you that it was easier to do than describe, but don't hesitate to ask if you not sure about any points. Filing down the spur gear was perhaps the most worrying part, but with a four cut fine file it was no problem.

I've still got the the Scalefour digest 41.7.1 (Highlevel gearbox profiles printed on drafting film) and I've tried this against the J15 diagram from the kit, and I agree that the amended Loadhauler compact + + D2 Drivestretcher should fit pretty well with the gearbox going up through the firebox so you can model he firebox front if you feel the need.

Will

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Pickups for the J10

Postby Will L » Thu Jan 17, 2013 7:21 pm

Long posting warning, reading should not be attempted if you’re in a hurry

Preamble

A long time ago, in a galaxy far, far away, or at least at the beginning of this thread in 2010, this photo of the tender chassis from my O4 gave rise to a couple of questions about the pick-ups I had fitted. These questions I dodged at the time.
csb 04 3.jpg

I think it is fair to say my pick-ups do have a style of their own, which may be of interest to other people, and I did promise further explanation. But, until now, that explanation has not been forthcoming. Well the J10 has got, slowly, to the stage when the CSB work is done, but the nature of the pick-ups is still relevant in the CSB world, and the relationship between the two even got a mention elsewhere recently.

So I've decided that the time has come to explain exactly what, pick-up wise, is going on under my locos, with particular reference to the J10. I‘ll accept right now that this will all look a bit over complex to some of you, but I would rather see it as a highly evolved approach to pick-ups, developed over a lot of years to meet a growing understanding of what I was trying to achieve. Or some load of bulsh1t like that.

Let’s start here

Just like the O4 the J10 tender does the bulk of the work pick-up wise. This is the CSB fitted tender chassis to which top wiper pick-ups are to be fitted. How it came to look like this is explained way back up this thread somewhere.
CSB J10T 16  Bare Chassis .jpg
CSB J10T 16 Bare Chassis .jpg (98.35 KiB) Viewed 7503 times

And, so you can see where we are going, here are the assembled pick-ups.
CSB J10T 18 tpicup.jpg
CSB J10T 18 tpicup.jpg (177.29 KiB) Viewed 7503 times

You will note that it features pick-ups made from Phosphor Bronze (PB) wire and incorporating a wound spring. These are mounted on to hard brass wire bus bars which I use to carry the fixed electrical paths round my locos, which in turn run back to a Printed Circuit Board (PCB) pad which bolts to a convenient place on the chassis.

I find that the spring wound pick-ups gives me much better control over their business end, while keeping the pressure placed on the wheel to a minimum. The longer the unsupported length of wire, the less the pressure applied at the tip. I.e. the pick-up is softer. However long strait(ish - PB wire is resolutely curly) wires are hard to convince they want to stay exactly where you want them and are highly susceptible to accidental “re-adjustment”. Including a wound spring section significantly increases the length of the wire. While the shape does lose some of the flexibility gained by this increase, it makes keeping the tip in play significantly easier.

I started fitting hard brass wire bus bars as part of my loco pick-ups, partly to minimise the amount of flexible wire floating around inside the loco and partly to provide a means of making a attachment points for the individual pick-up wires exactly where I need them. This being a preferable alternative to having either multiple PCB pads to mount the pick-ups on, or trying to bend complex shapes out of springy, not quite strait, PB wire to get from a centrally placed PCB pad to wheel rim, and missing all sorts of opportunities to cause short circuits on the way.

I claim nothing original in either of the above, but the thing which, as far as I know, is uniquely mine, is the way the ends of the bus bars are carried down the centre of the spring section of the pick-up wire. The observant will have realised that the PB wire is not solder to the end of bus bar wire it is associated with, it is actually attached some way from the end, and in this example could apparently have been fitted directly to the PCB pad. What those bus bar ends are giving me is both an assembly technique which means I can easily solder the pick-up wires in place with little further need for adjustment and a method of adjusting them easily if/when that does become necessary.

When I first fitted pick-ups with the integral wound spring section, I did find that the required final adjustments weren't all that easy. Typically you wanted to limit any adjustment to the last strait section of wire, but actually achieving this required you to find a way of holding the spring firmly in its place while you did it. My solution was to wind the springs round a piece of tube that was a sliding fit over the bus bar wire, and to run the end of the bus bar up the centre of where you wanted the spring to be placed. So for fitting and adjusting, slipping a piece of tube inside the spring and over the end of the bus bar holds the spring section in exactly the right place while you work on it.

Enough of my ramblings, let’s see that in pictures.

Making the springs
CSB J10T 14 pb 1.jpg

1. The spring is to be wound around a piece of tube which has an internal diameter which is a good fit on the 0.7mm brass wire I use for my bus bars. Mount the tube in a pin chuck and make a 90 degree bend in the PB wire with a tail of about 1 cm.
2. Push the tail of the wire down the side of the tube using the slot in the pin-chuck chuck. (couldn't resist it)
3. Form the spring by turning the pin-chuck while holding the wire taught
4. The finished article
N.B. the springs are handed, and typically you need equal numbers of both hands. The hardest bit is remembering to wind half one way and half the other.

Assembling the pick-ups
CSB J10T 17 pb4 .jpg

1. A left hand and a right hand spring, your choice which is which.
2. Start out with a PCB plate that fits the tray on the chassis. I use bits of a product called varoboard, used for building prototype circuits, because I have it about and it saves having to file gaps in the copper layer. The holes can come in handy too. I usually make do with one bolt to hold it down, but then I usually use a smaller PCB plate too. 0.7mm hard brass wire bus bars are bent up and soldered to the PCB, so as to produce ends where the spring wound section of the pick-ups are to be located. In this case in line with the wheel treads and 11 mm horizontally from the axle. I need one wire end per wheel, and conveniently the 4th end is used to mount the 2 pin socket which will eventually connect the tender pick-ups to the loco. The black and white lump in the original photo. The little kink in the middle of the bus bars is to ensure that both wires are soldered to two copper strips on the veroboard, thus avoiding putting too much strain in any one strip of copper.
3. The PB spring is mounted on the tube and the strait ends bent so that the business end of the pick-up lies in the angle between the wheel tread and the flange.
4. The tube holds the spring in the right place while the solder joint is made. You will remember that this is a sprung chassis, therefore, because the body weight is absent, the pick-up is now set so it is just in contact with the wheel tread when the suspension springs are uncompressed.

For further adjustment you simply reinsert the tube which holds the spring in place and gently tweak the tail.

QED

That’s more than enough for one post. There are some matters arising but they can wait for another post. Those of you wondering what, if any, pick-ups got fitted to the loco will find the answer there.

David Knight
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Re: Loco Suspension, fitting CSBs

Postby David Knight » Thu Jan 17, 2013 8:46 pm

Sorry if I missed it Will but did you mention the diameter of the PB wire? I've not been able to find it in any of the references. That said, 'tis an elegant looking solution to the problem of pickups.

Cheers,

David

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Will L
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Re: Loco Suspension, fitting CSBs

Postby Will L » Thu Jan 17, 2013 11:36 pm

davknigh wrote:Sorry if I missed it Will but did you mention the diameter of the PB wire?


No I haven't said yet but I will do in part 2 which will be along shortly.

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Re: Loco Suspension, fitting CSBs

Postby billbedford » Fri Jan 18, 2013 9:49 am

If you are going to use pickup like that why bother with CSBs?
Bill Bedford
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Will L
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Pick-ups for the J10 part 2

Postby Will L » Fri Jan 18, 2013 1:04 pm

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.

Using Rim scraper pick-ups

I’m personally not a great fan of live chassis locos. If they work for you, that's fine, and I suspect the 2mm brigade probably have little choice. Personally I think it easier to sort out unexplained short circuits if there are bits of your loco that ought to be electrically dead. I’ve found rim scrapers work for me, so I plan to stick with them. Proponents of split chassis, American pick-ups and the like are very welcome to explain their preferences, how can I put this, somewhere else.

Use of PB wire on steel rimmed wheels

I use phosphor bronze (PB) spring wire, usually 29 swg (about 0.35mm) because it combines good electrical conductivity with being relatively hard and wear resistant. I know it has been said that you shouldn’t be using PB on steel rims, and that we should prefer brass, nickel silver or such novelties as fitting little pads of gold at the business end of the pick-up.
While there is a whiff of truth in the idea that unlike metals can react,
- PB isn't notably different in this respect than brass or nickel silver
- The erosion effect requires the presence of an electrolyte, say salty water!
I tend not to run my pick-ups under water, salty or not, and despite having run PB pick-ups on steel wheels for a good few years now, I have seen no sign of any reaction.

If you want to know more, see this article on Wikipedia which, as I read it says that, were there was any truth in this idea, gold would be worse than PB.

Removable Pick-ups

I like my pick-ups to be removable. Like many people I started off sticking copper clad strips to various parts of the anatomy of my chassis and soldering the pick-ups there to. But since I worked out that life was simpler if I could drop out the wheels without disassembling them, it became clear it was better if you could remove the pick-ups as well.

Pick-up style

I always like my pick-ups to act on the running surface of the wheels, so that is only one part of the wheel I need keep clean. Putting this together with a preference for not putting my pick-ups where they are vulnerable to damage, i.e. hanging around underneath the chassis, has led to me favouring top wipers. These are particularly suited to fitting to tenders, and, in search of the maximum electrical track contact, I always fit pick-ups to tenders.


Use or top wiper pick-ups with CSB’s

We had to come back to CSB, but you don’t need to be all that clever to realise there are implicit contradictions in employing top wiper pick-ups on a CSB chassis. Having gone to all the trouble of accurately working out the fulcrum points for one set of springs, it does seem a trifle perverse to then stick on what are effectively an extra set. In my defence this has not been done without some soul searching, and I do take the following precautions so as not to upset the balance of my CSB calculations.

1. I ensure that the pick-ups are all the same length so that their contribution to each wheel set is roughly equal. Which is why in the example in part 1, each pick up is fitted the same distance from each axle, and 11mm was the longest pick-up length I could easily apply to all 6 wheels.
2. I ensure the pick-ups are as soft as possible, so the contribution of the pick-ups is negligible compared to the CSBs themselves.

As best as I can measure them, and its not easy, the pick-ups fitted to the J10 tender each apply a pressure of 2 to 3 grams at the CSB static deflection point, so the body will seem to the CSB’s to be 18 grams lighter than it actually is. Given that I’m expecting the all up weight of the tender to be in the region of 150 grams, the spread sheet tells me this is the equivalent to a change of 0.2 of a thou in the CSB wire size. I think I can live with that.

Other applications - The C12

The picture below shows the set of pick-ups fitted to the driving wheels of the C12 which featured in the CSBs and the Single Bogie thread.
CSB C12 pickup detail.jpg

Again top wipers fitted to a CSB chassis. This time they could be made even longer, so long in fact that keeping them on the wheel treads still proved problematic. As a result they are bent to hook over the wheel flange. These little bends are tricky to get right, which is why I don't use them if I don't need to. Note the use of the bus bar to carry the electrical circuit past the gear box and down to the rather different pick-ups fitted to the bogie. These have already been described in the thread referenced above.

Like the J10 tender, the feed to the motor connects to a two pin plug mounted on the pick-up PCB pad were you can't see it in this view. This is another consistent feature of my pickup design. Connecting your motor like that makes ensuring your locos don’t go the wrong way simple, and will make life much easier should I ever wish to go DCC.

And finally, so what about the pick-ups on the J10 loco?

On this occasion, it wasn’t practical to fit top wipers on the loco, which features a cast white metal footplate and hence no space to hide clever stuff between there and the wheel tops. In fact it wasn’t at all clear how best to fit pick-ups to the front axle at all, without un-prototypical appendages being clearly visible between the frames under the boiler. Ok, yes that space should be full of valve gear slide bars and other similar stuff, but just because there is an absence of stuff that should be there, that is no excuse for displaying all sorts of stuff which shouldn’t be. Given that there was going to be 6 wheel pick-up on the tender, the decision was taken to forgo pick-ups on the leading axle. There follows the view from below.
CSB J10T 13 pickups.jpg

The pick-ups are on the second and third driving axles. They are fitted below the frames and rub on the edge of the wheel flanges which is close enough to the running surface. They are arranged so as not to deprive the CSBs of any of the loco weight. The construction style should now be familiar, but in this case the bus bar ends and the spring wound section of the pick-up are mounted vertically. Also note the bus bars carrying the pick-up circuit to the flexible connection to the tender, masquerading as the water pipes, which you can see, and the two pin socket which connects to the motor and which is mounted above the PCB plate, which you can’t.

I think that's enough from me for now

Will
Last edited by Will L on Sat Jan 19, 2013 11:51 pm, edited 2 times in total.

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Russ Elliott
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Re: Loco Suspension, fitting CSBs

Postby Russ Elliott » Fri Jan 18, 2013 1:49 pm

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. 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.

beam-v-pickup-force.gif
beam-v-pickup-force.gif (4.77 KiB) Viewed 7338 times


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