CSB Starter - LMS 4F Tender

[peterbkloss]

Having read through the guides on the forum about the merits of CSB vs trad 3 point compensation (that I've used so far) I thought it about time to dip my toes in and what better way than to use it on the tender chassis for my 4F (separate thread) as there are no worries to do with precise axle spacing or gearbox widths and I can concentrate on the basics of getting CSB to work and gain some experience.

Having said that, I've set myself a high bar by choosing to adapt a Comet tender chasssis etch that lacks meat in both the main frame and the sticky down bits for the wheels since 'Mr Comet' decided to make a chassis so you could simply drop the wheels into sans bearings or other complications. Why use a Comet chassis to start with - because before I even dreamed of trying CSB, many moons back, I bought a few thinking they were a good idea and now being an expat pensioner I can't afford to just trade them for something better like a full blown Lanarkshire models kit that would save me all this effort

For the adaption therefore I opted to use Highlevel miniblox and carriers since I could remove less metal from the rather thin axle slots. In fact I've tried to use the minblox themselves without the guides and make guides to stop them rotating from scrap brass strip. Nasty, but if I can get this to work then anything else will be easier. I had to wait for these to arrive with Lanarkshire models anchors and wire courtesy of my Christmas family visitors so in January, having reached the point with my 4F that I really needed to have the tender ready to roll I made a start.

Oh a disclaimer - eveything I've ever 'learnt' before this has come from the excellent blogs on the topic in this forum and I'm very grateful to Will L for his particular guidance that I hope I haven't trashed / ignored in the following

To the CSB experts this isn't rocket science but for me it is breaking new ground!

Firstly I tackled the anchors - drilling holes on the frame centre line, not optimal as I would probably need to use the carriers top slot but with so little frame depth and ready made holes on the centre line for the two mid anchors that was the way to go. I drilled holes for the outer anchors 7.5mm from the outer axle centre line as per the values from Will L's spreadsheet:

IMG_2268.jpg

Next I opened out the slots to about 3.5mm (just under) for the hornblocks to be a sliding fit. This is the least satisfactory part as I didn't bother to make a jig and I 'should have' as they are not that straight or accurate. Next time. (Or if they stick or drop out I'll widen the slots slightly more and solder in the hornguides I didn't use). Then soldered the anchors in with .45mm hard brass wire to hold them in line:

IMG_2279.jpg

Then afterwards soldered the frames to the supplied EM frame spacers. I used only one centre spacer as I thought two would make it too crowded. Here another problem emerged that the spacers (horizontal flat part) sit very close to the anchors (the lack of vertical meat problem here shows big) so bigger holes than I initally thought were required where the wire will go through, and indeed I had to make them bigger in the end spacers later on as the initial cut was too small ...

IMG_2300.jpg

Then hornblock and carrier assembly, for such small blocks quite fiddly, held together by a screw whilst soldering. I have to say I'm at the limit of my eyesight here even with a head magnifier so a challenge for me. I made the first fold in the carriers before soldering to avoid the that joint half etch filling before I could fold it (!):

IMG_2302.jpg

Then some scrap edge strip to prevent rotation had to be added to one side of each bearing slot, and then trial fit of the bearings (a bit of fettling with the file) and carriers, and then threading through the 10 gauge wire (another eyesight and hand movement challenge). 10 gauge is my starting point wire thickness (100-150 gram total weight per the spreadsheet):

IMG_2343.jpg

IMG_2345.jpg

at this cruel enlargement one of the centre axle carriers is not vertical - I've only just seen this as of writing!

then attaching wheels and even with no quartering I used the GW press:

IMG_2396.jpg

IMG_2400.jpg

a quick push around the layout and it didn't fall off with my most indifferent trackwork, so in that sense it has proved itself

Then a trial fit against the Airfix tender base to see how much plastic needs to be removed. At bit of cutting and filing and here it sits very roughly:

IMG_2398.jpg

The frame sat too far forward and so I needed to cut some off the back as the back edge of the guard irons are almost flush with the buffer beam edge. Trial fit again with some fixing screws front and back and with the tender top:

IMG_2445.jpg

plus a ride height check with my coupling height gauge. No additional weight inside yet so this will need adjusting (maybe putting the CSB wire in the next hole down ...)

IMG_2443.jpg

And then sitting against the loco on track:

IMG_2447.jpg

So good so far, now to make a pickup pcb with coil sprung pb wire just like Will L and Barrow Road have exemplified ....

[Winander]

Then some scrap edge strip to prevent rotation had to be added to one side of each bearing slot

Wouldn't the wire through the carrier be sufficient to prevent rotation?

[Will L]

Having read through the guides on the forum about the merits of CSB vs trad 3 point compensation (that I've used so far) I thought it about time to dip my toes in and what better way than to use it on the tender chassis for my 4F (separate thread) as there are no worries to do with precise axle spacing or gearbox widths and I can concentrate on the basics of getting CSB to work and gain some experience.

A tender is a great place to start so its a good choice. All seems to be going well so far.

A quick tip for the future (I'm not suggesting you change anything), when fitting the fixed fulcrums, life is simpler if you make sure the wire path is as strait as possible, as this makes putting the wires in easier. Before you solder in the fixed fulcrums, thread the axle blocks and fixed fulcrums on the wire in the right order and then assemble them them loose on the chassis side, the distance of the wire from the chassis will be set by the axle block fulcrums. Then solder the fixed fulcrums in like this.

[peterbkloss]

Having read through the guides on the forum about the merits of CSB vs trad 3 point compensation (that I've used so far) I thought it about time to dip my toes in and what better way than to use it on the tender chassis for my 4F (separate thread) as there are no worries to do with precise axle spacing or gearbox widths and I can concentrate on the basics of getting CSB to work and gain some experience.

A tender is a great place to start so its a good choice. All seems to be going well so far.

A quick tip for the future (I'm not suggesting you change anything), when fitting the fixed fulcrums, life is simpler if you make sure the wire path is as strait as possible, as this makes putting the wires in easier. Before you solder in the fixed fulcrums, thread the axle blocks and fixed fulcrums on the wire in the right order and then assemble them them loose on the chassis side, the distance of the wire from the chassis will be set by the axle block fulcrums. Then solder the fixed fulcrums in like this.

Aha Will I have the 'opposite' problem in that I bought Lanarkshire models CSB Anchors that (by the looks) expect that one will have fitted hornguides of some kind inside of the frames to which the anchors are attached. As I 'cheated' and just filed slots for the bearings the anchors stick out further than carriers. I thought I might hit that problem but the misalignment is not as bad as I feared and it all seems to slide OK. Else I would either need to insert the miniblox hornguides with a little more filing of the slots to take the outer face of the bearings or source anchors with no flange (some kind of plain shanked handrail knob). Thanks for the tip anyway, much appreciated!

BTW what is your feeling about Winander's comment about the wire 'holding' the carriers/blocks vertical? I found that my bearings 'flopped' without guides, but I am using the thinnest wire ....

[ianpenberth]

BTW what is your feeling about Winander's comment about the wire 'holding' the carriers/blocks vertical? I found that my bearings 'flopped' without guides, but I am using the thinnest wire ....

I wondered too - tried it on the first PenBits test etch. They flopped...

[Paul Willis]

Aha Will I have the 'opposite' problem in that I bought Lanarkshire models CSB Anchors that (by the looks) expect that one will have fitted hornguides of some kind inside of the frames to which the anchors are attached. As I 'cheated' and just filed slots for the bearings the anchors stick out further than carriers. I thought I might hit that problem but the misalignment is not as bad as I feared and it all seems to slide OK. Else I would either need to insert the miniblox hornguides with a little more filing of the slots to take the outer face of the bearings or source anchors with no flange (some kind of plain shanked handrail knob). Thanks for the tip anyway, much appreciated!

You're clearly going great guns at the moment, so no comments on the tender under construction.

For future reference, I get around exactly this "depth" problem by using Alan Gibson shoulderless handrail knobs. Having just a long plain stem, the depth can indeed be set to match whatever your wire and bearings need it to be, if that makes sense.

Once the handrail knob is soldered in at the correct depth, the excess length protruding from the outside of the frames is simply snipped and filed off. This is just another case of being aware of the right tool/part for the job makes it so much easier.

HTH
Paul

[Jol Wilkinson]

London Road Models supply an etch of hornblock CSB adaptors (which fit their own and HL hornblock bearings) This includes a variety of etched wire retainers that have short horizontal slots for wire (which are aligned with the bearing adaptor) so allowing a small amount of horizontal movement (there are also other items on the etch for using wire springing).

CSB adaptors.pdf

[Will L]

London Road Models supply an etch of hornblock CSB adaptors (which fit their own and HL hornblock bearings) This includes a variety of etched wire retainers that have short horizontal slots for wire (which are aligned with the bearing adaptor) so allowing a small amount of horizontal movement (there are also other items on the etch for using wire springing).

CSB adaptors.pdf

Sorry Jol the PDF that loads for me is blank

I assume you mean this

[Jol Wilkinson]

I don't no what happened there, Will.

The download was just the drawing of the CSB single point mounting from the instructions. I felt that was the most relevant bit to the discussion. Clearly something went wrong with exporting from CorelDraw to a pdf.

It was meant to be this.

CSB adaptor and mounting.pdf

[zebedeesknees]

The download was just the drawing of the CSB single point mounting from the instructions. I felt that was the most relevant bit to the discussion.

CSB adaptor and mounting.pdf

Shouldn't that be described as a 'DSB' Jol?

Discontinuous...

Ted.

[Jol Wilkinson]

Ted,

the drawing simply shows how the hornblock, etched adapter and the etched csb mountings relate to each other. I would have thought that was obvious.

Jol