Chassis kits for CSB

NickM
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Chassis kits for CSB

Postby NickM » Sun Aug 04, 2019 7:13 am

Hi, I’m new to Scalefour and this is my first post.

I have read a fair bit on CSB in the Scalefour forum, and I think I have a basic understanding of the principles, but I have no experience building one.

I have built and converted to P4 a few locos, High-level (14xx, compensated), Comet (57xx, individually sprung) and CSP (Hawthorn Leslie, fixed) chassis.

I’m most interested in smaller locos and industrial, and slow running. I’ve been focussed on GWR 1920-30’s, but not limited to that region.

My question; is there a chassis kit that is particularly suited for conversion to CSB, or already includes CSB? I am not intending to convert any of the existing locos to CSB at this stage but may try later.

What are the things I should look out for? Are some hornblocks easier/work better for CSB?

I realise this is a very general question as I don’t have a specific loco in mind yet.

Nick

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grovenor-2685
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Re: Chassis kits for CSB

Postby grovenor-2685 » Sun Aug 04, 2019 9:23 am

Hi Nick, Welcome to the forum.
Bill Bedford does CSB chassis kits and this one is GWR http://www.mousa.biz/fourmm/loco/frames/gwr_loco_frames4.html
High Level does hornblocks and bearings designed for CSB as well as Jigs for using them, but I.m not sure if any of his kits are suplied with them.
http://www.highlevelkits.co.uk/hornblockpage.html
Regards

NickM
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Re: Chassis kits for CSB

Postby NickM » Sun Aug 04, 2019 11:36 am

Hi Keith,

Thanks, that's very useful, I had not spotted the Bill Bedford chassis - that 56xx may be exactly what I'm looking for as I have a heavy tank body waiting for a chassis.

Nick

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Will L
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Re: Chassis kits for CSB

Postby Will L » Sun Aug 04, 2019 12:58 pm

The Highlevel hornblocks are, as far as I know, the only once which directly support CSB use, and they also sell a jig for marking out the fulcrum points which I find very handy for adding CSB's to existing kits. Although only a very few of the the excellent Highlevel chassis and loco kits have CSB use designed in. The Bill Bedford kits are CSB based. They do the job in a slightly different way, but achieve the same effect.

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Noel
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Re: Chassis kits for CSB

Postby Noel » Sun Aug 04, 2019 1:12 pm

Rumney Models does two CSB chassis using Highlevel hornblocks: http://website.rumneymodels.co.uk/steam-locomotive-chassis
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Noel

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PeteT
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Re: Chassis kits for CSB

Postby PeteT » Sun Aug 04, 2019 3:25 pm

Rumney also do CSB adapter plates for the Comet/Brassmasters/Markits hornblocks. There is a topic on my workbench about using these with a Comet Ivatt tank chassis, with Markits WD handrail knobs.

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David B
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Re: Chassis kits for CSB

Postby David B » Sun Aug 04, 2019 5:19 pm

The Brassmaster horn blocks with carrier plates are used on Jeremy's new steam railmotor.

NickM
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Re: Chassis kits for CSB

Postby NickM » Sun Aug 04, 2019 8:31 pm

Thanks, everyone - really appreciate all the replies.

I'm going to be busy!

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JackBlack
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Re: Chassis kits for CSB

Postby JackBlack » Mon Aug 05, 2019 7:53 am

There's a good article here with photos showing conversion of a High Level Pannier chassis to CSB:

http://www.clag.org.uk/pannier-csb.html

davebradwell
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Re: Chassis kits for CSB

Postby davebradwell » Wed Aug 07, 2019 10:26 am

Now that this thread has settled, it's a good opportunity to remind a generation spared the task of routinely dismantling their car engine the need to number axleboxes and hornguides so that the chassis can be re-assembled with these bits in the same place and orientation every time. Each axlebox will be just a little off-centre by different amounts and the jigging compensates for this, or tries to. If you shuffle the bits round you're in trouble. Failure to carry out this basic procedure means when you're chasing that last little tight spot you'll be going round in circles chasing a ghost.

Referring to the last article, it would seem strange carefully designing your suspension and then adding pick-ups which also press downwards on the wheels. I can only see a safe use for such pick-ups on rigid axles. The horizontally acting type on the flange corner was Guy Williams preferred type and he claimed to have tried all types, which was good enough for me. It seem here, however, that they weren't acting very horizontally so perhaps needed more thought rather than replacement.

DaveB

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David B
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Re: Chassis kits for CSB

Postby David B » Wed Aug 07, 2019 11:04 am

davebradwell wrote:Referring to the last article, it would seem strange carefully designing your suspension and then adding pick-ups which also press downwards on the wheels.


I use top-wiper pick-ups where possible because they are less liable to be damaged being hidden and away from fingers. The phosphor bronze wire has no discernible effect on springing. The wire is very thin, brushing the tyre and exerting little downward pressure as it's ends are free, not restricted as they are with the CSB.

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PeteT
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Re: Chassis kits for CSB

Postby PeteT » Wed Aug 07, 2019 11:42 am

davebradwell wrote:Now that this thread has settled, it's a good opportunity to remind a generation spared the task of routinely dismantling their car engine the need to number axleboxes and hornguides so that the chassis can be re-assembled with these bits in the same place and orientation every time. Each axlebox will be just a little off-centre by different amounts and the jigging compensates for this, or tries to. If you shuffle the bits round you're in trouble. Failure to carry out this basic procedure means when you're chasing that last little tight spot you'll be going round in circles chasing a ghost.


The carriers I designed for the Comet/Brassmasters/Markits block, as mentioned earlier, (available through Rumney) have each one lettered/numbered for ease of identification - not that it isn't easy enough to mark each one while pairing them up.

Enigma
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Re: Chassis kits for CSB

Postby Enigma » Wed Aug 07, 2019 3:26 pm

The Branchlines/South East Finecast 16xx chassis has CSB points etched in - but as it was designed by Justin then I'm not surprised!

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Will L
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Re: Chassis kits for CSB

Postby Will L » Thu Aug 08, 2019 4:53 pm

davebradwell wrote:Now that this thread has settled, it's a good opportunity to remind a generation spared the task of routinely dismantling their car engine the need to number axleboxes and hornguides so that the chassis can be re-assembled with these bits in the same place and orientation every time. Each axlebox will be just a little off-centre by different amounts and the jigging compensates for this, or tries to. If you shuffle the bits round you're in trouble. Failure to carry out this basic procedure means when you're chasing that last little tight spot you'll be going round in circles chasing a ghost.

Absolutely right, you need to remember it during the original assembly process too. I centre pop the bottom of the axle boxes, 1 pop for the left side and two for the right (ensures they are on the corect side and the correct way up) then pop the outer face of the end bearings so the pop will be to the end. The middle one needs none (unless your building something with more than 6 couple axles). I also centre pop the frame sides the same way, and anything else you need to be sure its on the right side (coupling rods sometimes) and even my GW wheel press,
Referring to the last article, it would seem strange carefully designing your suspension and then adding pick-ups which also press downwards on the wheels. I can only see a safe use for such pick-ups on rigid axles.

I worried about that too, as yes I do appreciate that the two things do seem to be working against each other and might invalidate the big selling point of CSB, that it allows you to design in the correct spring rate on all wheels (hence avoiding the near impossible task of tuning individual spring to anything like the same accuracy).

However in the end I decided that,
1. given my design of top wipers gives a really soft spring, and
2. the resistance put up by the wipers is a differer order of magnitude less than the CSB wire (a lot longer, a lot thinner. only supported at one end and with a significantly lower modulus of elasticity if you use PB)
3. they don't significantly affect the design calculations to get the right spring size.
And any minor effect was far outweighed by getting the pickups on the one part of the wheel that needs to be clean, and out of the way of finger damage.
The horizontally acting type on the flange corner was Guy Williams preferred type and he claimed to have tried all types, which was good enough for me. It seem here, however, that they weren't acting very horizontally so perhaps needed more thought rather than replacement.

I agree this type are good too and I will use this sort if I cant get top wipers in. Of coarse it does cross the mind that there is an issue that anything that presses horizontally on a wheel hard enough will effect the action of any suspension system (sprung plunger pickups being the prime example) but, so long as they are soft enough...

davebradwell
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Re: Chassis kits for CSB

Postby davebradwell » Fri Aug 09, 2019 10:51 am

I'll repeat my assertion that having 2 different downward acting springs is not sound engineering design. The fact that one is probably much greater than the other doesn't really excuse it as there are other ways of implementing the pick-up function so the compromise is totally unnecessary. In any case Guy Williams warned against picking up on the tyre but doesn't give any reasons. I don't doubt that the model in the photo works, I just questioned whether the design was optimum. Perhaps it just needs another csb for the pickups to get the downward pressures all the same - or simple compensation.

The horizontal wire pick-up has significant vertical flexibility so can move with the wheel. Eventually you have to accept some compromise, and this type is probably just the best of a bad bunch as our split frame friends will soon be reminding us.

I note the unnecessary swipe at the mature design of springing which I use and which might threaten my commercial arm. You prefer a non-adjustable design, WillL, whereas I won't build a model without adjustments on the springs. Both are perfectly valid design approaches largely based on how we choose to build the rest of the model and what it has to do to justify its existence. It boils down merely to personal preference.

DaveB

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Noel
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Re: Chassis kits for CSB

Postby Noel » Fri Aug 09, 2019 11:56 am

davebradwell wrote: In any case Guy Williams warned against picking up on the tyre


Sorry, Dave, you'll have to explain that one for me, since there doesn't seem to be anywhere else to do it, plastic not being very conductive...
Regards
Noel

Philip Hall
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Re: Chassis kits for CSB

Postby Philip Hall » Fri Aug 09, 2019 1:21 pm

I think what Guy meant was picking up from the running surface of the tyre, as it tends be the part of the tyre that picks up the most muck. A wire bearing on the edge of the flange is in many respects self cleaning. I thought what Guy wrote made sense and have always avoided top mounted pickups, or any other position where the wire bears on the running surface.

I agree with Dave. There are many ways of suspending a set of wheels, there is no one best path. I prefer compensation, or in many cases a ‘rigid’ chassis if I am doing a conversion. They all work impeccably, or I wouldn’t do it!

Philip

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zebedeesknees
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Re: Chassis kits for CSB

Postby zebedeesknees » Fri Aug 09, 2019 2:08 pm

Dave Bradwell wrote: I just questioned whether the design was optimum.

Ahhh, optimum for what? Current collection, weight distribution, haulage, ease of assembly/adjustment, or something else?
Perhaps it just needs another csb for the pickups to get the downward pressures all the same - or simple compensation.

Some contrast there! Which optimum does simple compensation satisfy? And at the expense of which others?
The horizontal wire pick-up has significant vertical flexibility so can move with the wheel.

So does the horizontal part of suitably designed top wipers. A stylus design running on the tread keeps the that clean too. If there is room to make the horizontal part long, say 15mm, the downward pressure will be minimal compared with the weight of the loco bearing on the axle. Writing of which, do we have any actual measurements to support some the assertions that come from all sides on this subject? Like axle weights, and comparisons of pickup arrangements thereon. Assuming that the unsprung weight of a motor and/or gearbox rests on a sprung axle, would that have more or less effect on the measured weight on that axle than top wiper pickups? And does anyone take that into account?
Eventually you have to accept some compromise, and this type is probably just the best of a bad bunch as our split frame friends will soon be reminding us.

I would remind them that a rolling pickup is the worst possible way of current collection, especially if the chassis is rigid. Scrapers of some sort are better, they keep the contact point relatively clean. Far the best is battery power and radio control - no pickups at all, unless you model 3rd, 3rd and 4th, or OLE and get it 'all right', that is... Come and talk to Nick or myself at Scaleforum if you are interested.
It boils down merely to personal preference.

So true.. Do I want to fiddle with adjusters on each wheel, in the hope of getting it right, while looking for one specialised part that escaped during the process (Thanks to DB for replacing it, but would prefer that it was something I could obtain from stock or make myself) - or use a self adjusting design made from stock proprietary parts? My personal preference should be obvious...

WillL wrote:I agree this type are good too and I will use this sort if I cant get top wipers in.

Will, I had this issue with my High Level 'Coronation'. It is possible to coil the pickup behind the brake shoes and have a stylus pressing horizontally, as in the pix on the CLAG site. It needs some pre-planning though...

Ted.

Julian Roberts
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Re: Chassis kits for CSB

Postby Julian Roberts » Fri Aug 09, 2019 8:04 pm

Does anyone know how development for the High Level chassis kit for a J50 is coming on? Apparently it is going to be CSB only.

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Jol Wilkinson
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Re: Chassis kits for CSB

Postby Jol Wilkinson » Sat Aug 10, 2019 7:24 am

Julian,

why don't you ask Chris Gibbons, he will know.

Jol

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Will L
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Re: Chassis kits for CSB

Postby Will L » Sat Aug 10, 2019 8:20 am

Philip Hall wrote:I think what Guy meant was picking up from the running surface of the tyre, as it tends be the part of the tyre that picks up the most muck.

Is that as a valid objection Phil? I'm with Ted, If the wheel surface is dirty enough to stop the rubbing contact pickup working it will be quite dirty enough to prevent rolling pick up from the rail. So your wheel cleaning requirement are no different and top wipers are hidden where you are less likely to accidental adjust them while your doing the clean.

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Will L
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Re: Chassis kits for CSB

Postby Will L » Sat Aug 10, 2019 8:21 am

Woops I seem to have hiccups, or at least my internet does.
Edited to remove a duplicate post
Last edited by Will L on Sat Aug 10, 2019 8:37 am, edited 1 time in total.

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Will L
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Re: Chassis kits for CSB

Postby Will L » Sat Aug 10, 2019 8:35 am

zebedeesknees wrote:
WillL wrote:I agree this type are good too and I will use this sort if I cant get top wipers in.

Will, I had this issue with my High Level 'Coronation'. It is possible to coil the pickup behind the brake shoes and have a stylus pressing horizontally, as in the pix on the CLAG site. It needs some pre-planning though...

Hi Ted, it was a Highlevel Y5 I had in mind and getting any sort of pickups in there that were in keeping with the kit was an interesting challenge. I have since caught one of the pickups while cleaning the wheels and it is in need of repair, but it is such a fiddly job I have been putting it off.

Incidently I built the chassis to take CSB and found I had to revert to compensation as the loco fitted the motor like a glove and there was no room for the motor to move with a floating axle.

High Level Kits
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Re: Chassis kits for CSB

Postby High Level Kits » Sat Aug 10, 2019 8:56 am

I’m hoping to have the J50 model on the stand for Scalefourum, with the production versions to follow shortly after that. It will be CSB only, with removable cosmetic springs so the wheelsets can be dropped out.

CSBs have also been incorporated into the design of the J72.

4479
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Re: Chassis kits for CSB

Postby 4479 » Sat Aug 10, 2019 3:31 pm

You got there before me Chris. I've seen what you have sent to Mick W, which looks good.

For the benefit of Julian, who I know is interested in such matters, I can say that it ought to be fairly straightforward to convert the J50 chassis to adjustable leaf springs, using the High Level hornblock tags. Use a handrail knob on one side of the hornblock, and a short length of brass angle, drilled and tapped 10BA for a hollow grubscrew on the other - along the CSB datum. Individual springs can be 10thou guitar string with the end bent at a right angle, but you probably know that! The hornblock keepers should stop the springs from coming out of the bearings, but if you are worried, drill the grubscrew right through and use a longer tail.

Grubscrews are possibly the difficult item to source. I think Exactoscale may supply them, but DaveB might be able to advise. Alternatively it might be possible to use a short length of 10BA studding, or a take the head off a bolt, but drilling through could be an issue. I hold grubscrews in a collet in the lathe, but if you don't have the equipment you'll have to devise your own method. Maybe hold it in a pin vice clamped in a larger vice?

BobH


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