Etching concepts, and modelling! - currently 1P and Ivatt class 2...

[PeteT]

Having had various ideas for etchings over the last couple of years, but never having got round to reminding myself how to drive Autocad, this summer/autumn I finally got round to it!

The main driver was a set of window frames for Ilkley engine shed. Bill Bedford does Midland Engine shed windows, but the two types are larger and smaller than these - as one would expect! I have covered these in my layout topic, but include a photo here for info:

While I was at it, I got round to drawing a few other things. Here we have some concepts for Stones ventilators, aimed at LMS period 2 (and older) stock:

On the left is with vertical bars to represent the lines/gaps/joins between the sections. This will be easy to fit, and to my eye looks pretty convincing and would probably paint those bars black.

On the right is just a frame - this would need to work either with laser cut glazing, or potentially going back to the cable tie concept. When I was looking at those before, I was looking from the basis of using the edges of the tie as the border of the glasing unit. This mean it was fixed from the outside of the coach, so would need an awful lot of thinning down - very time consuming for a one off coach, let alone a rake or two. However with this frame fixed to the outside, the cable tie could be used mounted on the inside of the coach, which would remove the need for this thinning down.

I think the latter concept needs an actual test so I'll aim to get this done in the next day or two - but does anyone have any thoughts on either route in the interim?

Lastly, I am rather sold on the CSB concept, but also on the Brassmasters/Comet hornblocks. I did modify some with a handrail knob for my LMS 2P 0-4-4 tank (build covered on RMWeb) but thought an etched hanger would be a good idea, so that it could be designed to line up with a Markits WD handrail knob used in the frames.

This design has partially worked, though I neglected to notice that the two rings on each side of the block are actually different sizes! This is actually a good thing (if I had noticed it) as it means that rather than doing 1 design which leaves the springy beam marginally offset for hornblocks in the second orientation (the slot for the frames is not down the middle of the block, so that it can be turned around to allow for different amounts of side play) two different dimensions could be easily distinguished. The one I have done fits perfectly!

All in all a pleasing set of etches for a first set

[Steve Taylor]

Oh I might just have been led astray...... again.

You wouldn't be thinking of making those CSB hanger plates available would you?

[PeteT]

Hi Steve,

Now you're leading me astray - I'd only just convinced myself to leave those to one side for a while and come back to them once a few other projects had been finished! (ish!). They are something I am keen to play with though, so out they have come!

Theoretically yes I have no desire to keep things to myself, and am more than willing to make them available.

The minimum I want to do is sort a type A and type B (though the sideways offset is only 0.25mm so they will actually work fine as they are, but as they will be more difficult to line up on the side of the hornblock which has the smaller diameter boss, it seems silly not to do the job properly).

Another option I have been considering is adding cosmetic springs to the bottom (I think Chris Gibbons is doing (has done?) a similar thing with the spring hangers on the High Level options) - the logic being that if the CSB wire is holding the hornblock, then trying to fit in a keeper plate arrangement with the springs seems like doing the job twice. The question is how visibly different the springs are between different prototypes, and whether a generic offering would cut the mustard. However, a bracket on the bottom of the hanger could just be there to allow the springs from whichever frames are being used to be attached to it.

[martinm]

Pete,

Did you see Will's take on this?
Go to his post . . .

Buck Jumping on Mass - The Build Phase
Post by Will L » Fri Mar 25, 2016 1:16 pm
Part 4 – Preparing Highlevel The Horn Blocks…

i don't think HighLevel have produced any extended CSB plates yet.

The question is how visibly different the springs are between different prototypes, and whether a generic offering would cut the mustard.

There is a wide variance in springs, I think that

a bracket on the bottom of the hanger could just be there to allow the springs from whichever frames are being used to be attached to it.

This dropper would allow the easy attachment of the springs removed from the frames, or any other replacement castings.

regards,

martin

[PeteT]

Thanks Martin,

Yes Will's method is similar to what I was thinking - I was actually considering two tabs to feed out to the end of the springs to mount them, but a single tab down the middle would be a lot simpler. I had also forgotten quite what the High Level CSB drilling jig looked like - which as long as it allows for 3.5mm vertically from the axle centreline to the anchor hole then I can use this for my experiments. I have one somewhere so will dig it out when I'm home and check.

There is a lot of useful info covered in Will's topic so I'll make sure I go back for a thorough read to make sure I havent ignored anything before I proceed!

Cheers,
Pete

[PeteT]

I assembled a shed window before christmas, which looks good but has twisted a bit as I cut the support frame out. I like the two skin arrangement in terms of looking right from both the inside and outside of the shed, but it does mean that looking at it from the wrong angle you can see through what should be the full thickness frame of each pane:

The CSB hangers, other than the ring size issue, line up nicely with the handrail knob holes:

These are being tested on an Ivatt 2 tank (which I wasnt going to do until several other things had been finished, but there we are...) and I acquired a set of Markits double slidebar crossheads. These look a leap ahead of the cast Comet option, and come in two parts with a slide housing to sit inside the cylinder. The let down (for my prototype) is the shape of it - the Comet one (correctly, for an Ivatt 2) has angled corners of the central block, while the Markits one is square.

I am in 3 minds as to what to do:
- Use the Comet one for the Ivatt, and keep the Markits one for an application where square is correct (eg a Crab).
- Use the Markits one as is - accepting that the loss of 'look' will more than likely be made up for by smoother operation.
- Use the Markits one and work out a way to add triangles into the corners to improve the look.

[Mike Garwood]

Pete
Another option is to etch a cover to give the angled appearance of the Comet cross head...only need to be half etch. Solder to the Markit option - my preferred crosshead - streets ahead of anything else out there.

Mike

[PeteT]

Thanks Mike,

I had initially ruled out an etch due to adding bulk, but I've been back to them with my verynear & that looks like a good option.

I think for the look the running edges would need to be full thickness, which would also allow for the rivet runs to be depicted in between.

The Markits block could be thinned a bit without worry, & I agree that it's the best option I've seen on the market too.

Cheers,
Pete

[Andy W]

Surely you could simply file some thin overlays to solder on the cross heads rather than do an etch?

[PeteT]

Well I could, but there are some rivets ripe for representing (which I accept could be done with Archers), and I do have at least 2 tanks and a tender variant to do in time. An etch would be more precise than anything I knock up, but there is a lag in time and cost. Horses for courses...

I do appear to have found myself a can of worms here, however. I was principally working from the Ian Allan Locomotives Illustrated no 72 on the Ivatts, as it has the works photos whose colours nicely show things up (Page 7). In these, both class 2s have a solid crosshead, with a row of rivets top and bottom, and the drop link bolting onto the centre of the crosshead. The Ivatt 4 has a hole in the top of the crosshead, and the drop link bolts on with 3 bolts below the centre.

Going through other photos, in that book, in volume 5 of Essery & Jenkinsons illustrated history, and online, it appears that the class 2s gained the class 4 style of crosshead over time. I am currently unable to find a pattern - so it could be that they were all changed. Strange that they arent mentioned in the text of either book...

The early type is hard to come by in clear photos online (they can be spotted once youve determined the difference relatively easily) - but the best is here:
http://www.geograph.org.uk/photo/2781339

And 41324 3/4s of the way down this page, in 1953 - which is a late batch so it doesnt seem to be something that was only done on the first 10 (like the first chimney, for example):
http://glostransporthistory.visit-gloucestershire.co.uk/Push%20Pull%20YTT.html

The Later type is here:
http://www.train-photos.com/picture/number6138.asp

And nicely modelled in scale 7 in the bottom photo here:
http://www.cherryclan.com/2015/08/ivatt-2-6-0/

It could yet be a batch thing, so time to start myself a spreadsheet and see whether it tells me anything...

[PeteT]

So far it appears that all batches started with the 'type 1' and changed to 'type 2' in the mid 50s - but plenty more photos to peruse yet. I also notice, unsurprisingly, that the Brassmasters Ivatt 4, while keeping the original (Bachmann) cylinders, slidebars and crosshead, has a crosshead overlay. So one of tonights jobs is to dig out my kit for that and see how it comes. It does have the right look for the later variant. I'm not expecting to be able to obtain one separately, as being an etched part it will no doubt be in the middle of a sheet, but it should give me some ideas.

http://www.brassmasters.co.uk/images/Ivatt%20Mogul/Ivatt%20LHS.JPG

[45609]

Pete,

Here is a random survey of LMS crossheads for you. You might find it useful and I may have more when I get more time to look. Photo file names should be self explanatory. There appear to be a couple of types in general outline but the Jubilee cross head on the left hand side is different. IIRC this is a hangover for the crosshead driven vacuum pump drive arm that was removed early in the life of the loco.

Morgan

[Tim V]

Should have said Pete, I've got loads of photos of Ivatt class 2, of course, you're not around tomorrow....

[PeteT]

Thanks Morgan, useful selection - and all of the 'later' type Including the Ivatt 4, which looks identical as far as I can tell... The BR standards also use that type, so presumably someone was having an experiment on the Ivatt 2s initially and it was deemed enough of a failure to systematically replace them all.

I have so far only found 1 photo of the 'early' type after 1954, but I am nowhere near the end of the library yet. The date isnt specified, but it is of 46522 with a late crest on P242 of the illustrated history V5.

Thanks Tim, indeed I'll be up north (! - slightly less south...) tomorrow, but there is always next week. I presume most of your photos would be from this part of the world, but if you did happen to specifically have any of 41273, 41325 or 46493 in particular I would be especially interested.

Once I've been through the obvious candidates in my library I'll upload my spreadsheet in case it is of interest.

Cheers,
Pete

[PeteT]

Unfortunately (in terms of liking a bit of variety between locos of similar classes) all Ivatt's in my area had the later type crossheads by my period of interest...

My current thought is to draw up a complete new crosshead, using a layered etch approach. My only concern is how to design it in such a way that it can easily be cleaned up and so run smoothly. The Markits one is a brilliant thing, but doesnt have a slot wide enough for the Comet slidebars, and is the wrong shape, but gives some good ideas for the rod and tube for functionality.

Anyway, while that idea is sloshing around the brain, I have assembled the wheelsets onto the CSBs and successfully rolled the assembly around Ilkley, which it does very nicely. The motor mount has up and down movement with the axle, but is tethered by a wire soldered to the gearbox frame, which slides through a handrail knob in the frame.

The springs are hung off the bottom of the hornblocks, which was reasonably fiddly, but should be much easier with an etched support for these included on the hornblock CSB bracket so fewer pieces to clamp together for assembly.

I have built a couple of High Level Gearboxes before, and always gone down the glue route as per the instructions, but have never been entirely happy with it. Egged on by Morgan though, I gave soldering this one a go - I had been concerned about potential corrosion, or the steel needing more heat and so affecting the plastic gears - but I am very pleased with the result and really don't know what I was worried about...

The aim is to have coupling rods on for the next BS4 meeting at Gordons, which I guess will be the 31st, so it can be pushed around the curves on the test track. I doubt I'll have made much progress with the Brassmasters pony trucks by then, but you never know...

[PeteT]

Having progressed the rolling 6 coupled chassis to roll around including coupling rods (which took a bit of extra brainwork and chopping as the Comet coupling rods are not designed to be jointed properly at the knuckle (either on the crankpin or not at all!) my attention turned to pony trucks.

The first one (rear) has been built, as per the instructions. I next week to work out whether the pony or the frames need altering slightly to allow it to sit properly. The build was, in my eyes, definitely worth while - it looks much more prototypical than the comet version - but one of the hornguides is over etched and that was fairly difficult to form properly on the correctly etched one - but I think I got away with it! The springing method detailed on the clag site was employed, and also works well (on its own at least...)

The second one needs altering, as per Dave Holt's RMWeb blog, and I a decent photo from the KWVR restoration updates of 41241:

http://www.rmweb.co.uk/community/index. ... nk-trucks/

http://kwvr.co.uk/41241-ivatt-appeal/41 ... s-reports/

[Horsetan]

Fascinating

[PeteT]

Well theres been no direct progress on the Ivatt recently (a football related broken wrist/arm has hampered me, but I'm released from my cast next week). I have at least got around to playing with the CSB adapter plates for Comet/Brassmasters/Markits hornblocks.

These are lettered or numbered, to save them being marked on assembly to pair them to a slot, only for markings to be washed off while cleaning... it also readily shows which hanger is for 'thin' and 'fat' blocks in terms of which way around they mount in the frames. The boss on the hornblock is different each side, and I've done the job properly so that the hole in the hangers line up with the WD handrail knobs for both the fat and thin orientations.

The only planned tweek from here is to increase the length of the spring detail attachment spigot. It is fine for Comet designs where there is an upwards pin for use as the hornblock endstop, but not all chassis designs have these. Overlength is better to allow them to be shortened to length for a specific scenario, rather than having to lengthen them

All being well these will be available via Justin (Rumney Models) at Scaleforum, no idea on prices as yet.

(The other bits on the test etch are feet for the handrail stantions on my London Road 50' Cowans and Sheldon Turntable, so go with the stantions supplied by LRM. I'll hopefully get these fitted over the autumn).

[iak]

Mmmmmm, noted...

[Will L]

Excellent idea, I thoroughly approve

[PeteT]

Thanks chaps, glad they're of wider interest!

I'll make sure I have my Ivatt with me in September (though it hasnt progressed since a few people saw it at S4N!).

[PeteT]

After a so far flat out autumn, a day out with Clutton in Portsmouth on Saturday inspired me to get back to the work bench on Sunday.

This went back to the J39 rather than anything 'currently' progressing, but still. Good progress was made, which I'll update on tomorrow, but having got enough of the tender built to prove my tenderiser installation concept (aside from lateral play in the draft beam) this evening's task was to install some wheels...

I'm playing with Exactoscales for the first time on this, & presume there aren't any tender specific axles available - so thinned down the central plastic section on axles I have in stock for rolling stock wheels, which seemed to go ok. However, when installed the are an extremely tight fit in the Dave Bradwell tender frame.

I tried an Ultrascale wagon wheels, & that fits fine. Both ate 26mm axles (measured to confirm), so it appears to be the coning on the axle causing me grief.

I can't be the first person to try this wheelset/tender combination - has anyone else seen the same issue? & if so how was it solved? Is there a bearing out there whose cone matches Exactoscales wheels but which is deep enough to have the bearing surfaces in the right places in the hornguides?

[Guy Rixon]

Have you checked the pinpoints of the Exactoscale axles for malformation? I've found occasional units that have bad machining: the point has not been fully ground, leaving "wings" that make it look a bit like a spade drill. The length is correct, but the effective opening angle of the cone is much too large. I've had three like this in a few dozen axles, which is a bit poor for a high-end product.

[PeteT]

Thanks Guy - they didn't look bad, but a slight polish with wet & dry seems to have sorted it. As you say, a bit steep for a top end product... but who knows if Phil, or someone else, will bring the range back into production.

So the functional building blocks of the tender are not far off:

The motor fits within the superstructure sub frame with a couple of mm spare, which will allow for a flexible fixing to deaden the sound. Dave Bradwell's instructions suggest taking out an extra bit of the underframe base for a tender mounted motor, but I havent found this to be necessary - though to be fair the High Level tenderiser wasnt an option then!

The tenderiser has been built with the mid level drop. As can be seen, the motor shaft is just below where it will sit in the gear tower, which allows a base for the motor to sit on.

So far the only modifications to allow for the tenderiser are 2 holes drilled to allow the shaft to pass through, though this doesnt allow for any sideways movement within the tender so this will need to be rectified.

Lastly we have the difference in coning between an Ultrascale and Exactscale axle - though it appears this in itself isnt an issue.

Attention now needs to turn back to the loco... which has been started, and basically needs the hornguides and coupling rods assembing before the task of not mangling the Exactoscale driving wheels. I'll be honest though, things are pretty hectic so I'm not expecting to see a rolling loco chassis this year.

[PeteT]

While most of my modelling of late has been focussed on getting Ilkley as far as possible for its trip to Scaleforum, there was a bit of time set aside for putting a decoder and bogie pickups on the 1P. I'm pretty pleased with my method for the pickups. The coils are created by wrapping 33swg phospher bronze around a 1mm drill bit, and these extend to locate through small tubes on the loco mainframe. This not only allows the bogie to be easily removed but also creates a nice amount of centralisation springing.

Currently both pairs of pickups (these for the bogie, and those via the undertray from driving wheels) are both of plugs. These are in reality quite small at 1.25mm pitch, but still adds to the size inside the loco so for final assembly I may well go back to straight through wiring. There is a bit of room to be created as the cab floor is raised, and there is room in the bunker for the decoder.