Ivatt Class 2 2-6-2 tank

Dave Holt
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Ivatt Class 2 2-6-2 tank

Postby Dave Holt » Fri May 03, 2019 7:44 pm

Having completed the BR Standard 2 tank recently. my attentions have turned to finishing the Ivatt version, which I actually started before the Standard. For some years it has remained as a running loco but devoid of the finer details but I have now made some progress towards completion.
The model consists of a Bachmann body mounted on a much modified Comet chassis. This latter has much in common with the BR standard version, including the suspension arrangement and drive, but has full length frames to suit the body and detailed differences, as per the prototypes.
The detailing work so far includes the buffer beam gussets, foot steps and their support struts, the injectors ans associated piping. The steps are Comet brass castings, the piping is brass wire and the other parts are made from custom etchings produced to my specifications by Rumney Models. The injector bodies are certainly fiddly, being made from multiple layers of etched shapes to give the appearance of castings.
Here's the model in the semi-completed state it's been in for years, prior to dis-assembly to add the details.
Ivatt_2T_001.JPG

This what the prototype injector looks like, although this one is on a 2-6-0 tender loco (at the Severn Valley Railway). The mounting bracket and water feed pipe are different on the tank engines.
Ivatt_injector.JPG

From this, and some measurements i had previously taken from one of the preserved tank engines, I made various sketches to define the parts. This one shows the assembly and its position on the loco.
Ivatt_2T_004.JPG

Here are the made-up injectors on their mounting brackets with connecting pipes for one of them, laid out in roughly the correct positions.
Ivatt_2T_003.JPG

The RHS injector fixed in position below the cab.
Ivatt_2T_007.JPG

And the LHS with all the pipes bent to shape and attached, with representations of the securing brackets and clips. Also shown are the cab steps and the rear buffer beam gussets.
Ivatt_2T_005.JPG

On now on to the the sand pipes and brackets, which are fixed to the keeper plate.
Dave.
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Andrew Ullyott
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Re: Ivatt Class 2 2-6-2 tank

Postby Andrew Ullyott » Fri May 03, 2019 8:55 pm

Looking forward to seeing what you make of it Dave!
Is it me or did you cut down the coal bunker?
My injector looks nothing like the real thing I feel! I shouldn't have copied that article in the Modeller.
IMG_2276.jpg
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Dave Holt
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Re: Ivatt Class 2 2-6-2 tank

Postby Dave Holt » Sat May 04, 2019 8:39 am

Hi Andrew.
The coal bunker is off at present. It's a separate moulding and hadn't been well aligned at the factory on my model. Luckily, I managed to prise it off without damage, to be re-fitted later.
I wouldn't worry about the injectors. To be honest, from a couple of feet away, you can't really make them out anyway. It's just probably some mild form of OCD on my part.
Dave.

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Julian Roberts
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Re: Ivatt Class 2 2-6-2 tank

Postby Julian Roberts » Sun May 05, 2019 8:02 pm

OCD or not, and aren't we all in that boat in varying degrees? - it is very useful that you've commissioned those injector details Dave. The problem seems to me, if I am making kit x, how can I know that somewhere there may already be obtainable(through the good offices of someone like yourself) just the detail that I may spend hours making...or reluctantly deciding to leave off for lack of ultimate determination/time/rountuit...?

Your knowledge of the prototype is invaluable. As well as this beautiful modelling I like those articles visible in/behind the hornways!

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Horsetan
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Re: Ivatt Class 2 2-6-2 tank

Postby Horsetan » Sun May 05, 2019 10:38 pm

Dave Holt wrote:.....I wouldn't worry about the injectors. To be honest, from a couple of feet away, you can't really make them out anyway. It's just probably some mild form of OCD on my part....


....that said, it's probably the only correct set of injectors out there.....
That would be an ecumenical matter.

Dave Holt
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Re: Ivatt Class 2 2-6-2 tank

Postby Dave Holt » Sun May 12, 2019 2:22 pm

The chassis is almost complete, now. Just the cylinder drain cocks to represent. Needless to say, rather like the injectors, I cannot find any suitable commercial product for these. Brassmasters do a very neat cast brass LMS drain cock casting, but unfortunately they have a different operating arrangement from those fitted to Ivatt locos. This same issue arose on the Caprotti Black 5, so I already have sketches and a construction method for creating the correct type.
I took all the chassis components out into the garden to photograph them in the bright sunshine, resulting in the following photos. Hope they're of some interest.
First, the full set of chassis parts, laid out roughly in their relative positions.
Ivatt_2T_008.JPG

Next, two shots of the frames, which carry the bearing pintles for the pony trucks, injectors and pipes, foot steps, AJ couplings, steam heat pipes and the pick-ups (bearing on the top of the driving wheels).
Ivatt_2T_009.JPG

Ivatt_2T_010.JPG

Here's a rather better shot of the injector and support bracket than the one I posted previously (better contrast). The fairly innocuous looking injector feed sieve boxes caused no end of problems. I initially made them to scale and positioned them in accordance with the LMS GA drawing. Unfortunately, they fouled the crank pins on the rear coupled wheels by quite a bit. I tried to move them out but could not move the first one, even though the solder had melted. As I pushed out with iron tip, the block pinged off to reveal that I had pinned them in position, not just soldered! Having successfully moved them out, I eliminated the side play in the rear axle with thin washers, shortened the length of the crank pin bush to the minimum and replaced the nut with a modified 16BA. Even then, I had to grind away the rear of the re-positioned filters using a mini drill mounted disc. Phew! An awful lot of work for such small items.
Ivatt_2T_011.JPG

The keeper plate carries the sand pipes and rear sand boxes and also the mounts for the pony trucks.
Ivatt_2T_012.JPG

The brake gear is split into two sections. This is necessary because the single rear pull rod passes through the "A" frame of the rear pony truck!
Ivatt_2T_013.JPG

The cylinders and valve gear are a single unit to facilitate assembly and painting. The up-stand is the torque reaction arrangement for the Portescap gear box.
Ivatt_2T_014.JPG

The wheel sets have balance weights from custom etchings (by Rumney Models). All the commercial versions were the wrong shape and size.
Ivatt_2T_015.JPG

Finally, the two pony trucks. These represent the two different methods of side control used on these locos. The left hand truck has swing link control and fits at the front on Ivatt locos (at the rear on the BR Standard version, for some reason. Also used on the BR STd Class 3 tanks.). The right hand truck has spring control and is at the rear. This latter type was also used at the front of Flying Pigs and BR Standard locos with just one truck. The trucks are sprung using hair-pin wire springs and the top plate bears against the pintles mounted under the frames (mentioned above).
Ivatt_2T_016.JPG


Dave.
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Andrew Ullyott
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Re: Ivatt Class 2 2-6-2 tank

Postby Andrew Ullyott » Sun May 12, 2019 3:41 pm

Very impressive Dave. Yours seems to have a lot more bits than mine!

essdee
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Re: Ivatt Class 2 2-6-2 tank

Postby essdee » Sun May 12, 2019 5:12 pm

Super. Simply superb.

Cor!

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Julian Roberts
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Re: Ivatt Class 2 2-6-2 tank

Postby Julian Roberts » Mon May 13, 2019 7:03 pm

Fantastic, Dave. Thank you for putting all this here.

One aspect I'd be interested to understand better.

The trucks are sprung using hair-pin wire springs and the top plate bears against the pintles mounted under the frames (mentioned above).

I think I can see these springs. But on the Crab thread you said you also spring the axle within the pony truck. Is any of that springing visible here at all still, and is this a spring at each end of the axle or just at the centre?

Dave Holt
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Re: Ivatt Class 2 2-6-2 tank

Postby Dave Holt » Mon May 13, 2019 7:29 pm

Julian.
Sorry if I've caused any confusion by using different terminology but the method of springing is exactly the same as the Crab, or rather the Crab is the same as this, as this was the first loco to use the diagonal hair pin springs (also recommended by Brassmasters for their Ivatt truck etch). There are two springs, inside the front and rear faces of the truck, as mirror images. The short vertical leg is soldered into the corner. At the top are two or three small coils to give flex, then a diagonal leg runs down and across the truck, ending in a tail at right angles to and bearing on the top of the axle, so the axle has a spring at each end.
That is the only springing in the truck, so each spring pushes one end of the axle down onto the track and the opposite end of the truck up against the bearing pintle.
Hope that clarifies the arrangement.
Dave.

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Julian Roberts
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Re: Ivatt Class 2 2-6-2 tank

Postby Julian Roberts » Tue May 14, 2019 6:30 am

Thanks Dave. I've looked up the Brassmasters Ivatt truck instructions - they give this link which I think illustrates your description above

http://www.clag.org.uk/comet-pony.html

If required I suppose the spring force can be adjusted by varying the wire thickness and/or number of coils?

Philip Hall
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Re: Ivatt Class 2 2-6-2 tank

Postby Philip Hall » Tue May 14, 2019 3:12 pm

Lovely work Dave. I have one of these to do, having acquired a spare body recently, and I already have the wheels. I will use the Comet chassis, but won’t go anywhere as far as you have!

Philip

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Hardwicke
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Re: Ivatt Class 2 2-6-2 tank

Postby Hardwicke » Tue May 14, 2019 9:11 pm

This gives me hope (eventually) for my Bachmann Ivatt tank. I'm lead to believe it is not possible to covert the chassis easily and a replacement one is the only way to go. Very impressive work.
Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

Philip Hall
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Re: Ivatt Class 2 2-6-2 tank

Postby Philip Hall » Tue May 14, 2019 11:46 pm

Michael,

From the reviews I have seen it seems that the present Bachmann chassis fitted to the most recently released model is fully in line with their current standards and therefore should be no problem to convert. I could be wrong, and it depends of course how up to date your model is. Where I believe it falls down is that the body is virtually unaltered from the old model (the moulding that Dave is using here) so a fair bit of detailing would be needed. As I managed to get a spare body cheaply and have the wheels I fancy having a go at an etched chassis for a change. If I was starting from scratch I would be tempted down the conversion route.

Philip

Dave Holt
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Re: Ivatt Class 2 2-6-2 tank

Postby Dave Holt » Wed May 15, 2019 9:57 am

As Philip says, the body moulding is rather old (and not much improved on the latest version, as I understand) and is definitely not up to current RTR standards. Interestingly, on another web site, Larry Goddard made one of these tanks by replacing the boiler unit (not sure if it included the front part of the foot plate) with that from the much more recent and finer detailed 2-6-0 tender loco. Sounds like a lot of work but did result in a very nice looking model.
I'll just stick with the old Bachmann and try to improve the details - new chimney, top feed, dome, remove the moulded boiler bands, new hand rail stanchions, lamp irons, etc. The biggest structural job is to inset the cab doors which are wrongly moulded almost flush with the tank/bunker side on the Bachmann body. To allow the cab opening hand rails to be correctly located, I've had some custom etchings done for the door area, but fitting these will involve quite a bit of plastic surgery and, no doubt, some filling and rubbing down to hide the metal to plastic joints. I'll find out how hard this is to get a neat result in due course.
Dave.

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PeteT
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Re: Ivatt Class 2 2-6-2 tank

Postby PeteT » Thu May 16, 2019 9:32 pm

Inspirational stuff Dave!

I think I'm going to use the Millholme injector, it doesn't look bad but does need the bracket & possibly a bit of sprucing up.

Interesting to hear that you've done etches for the doors. I've got as far as cutting the old ones out, & was planning on drawing something up (the other alternative, as per the MRJ article, would be to re-mount the original moulding packed inboard with plasticard).

Talking of drawings, I have made some progress with the bunker ladder. I printed it out on paper & it follows the contours of the body well (having worked from the drawing) so that is a good start. I need to go & find a prototype to sort out some of the finer detail, and the bottom mounting bracket, so not sure quite when it will progress further - but hopefully in the not too distant future!

Dave Holt
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Re: Ivatt Class 2 2-6-2 tank

Postby Dave Holt » Sun Jun 16, 2019 8:39 pm

After a period of reluctance to actually do anything, I've finally roused myself to make and fit the cylinder drain cocks and operating mechanism to the cylinder/valve gear unit. To be honest, my efforts probably fall into the "artistic impression" category, rather than a scale reproduction. That said, the results better represent the type of cocks fitted to these locos than any of the commercially available versions, that I am aware of. Just need to re-fit the front cylinders cover , which fell off several years ago, to the LH cylinder to finish the chassis parts.
Then to the body. Argh......
Some shots of the drain cocks.
Ivatt_2T_018.jpg

Ivatt_2T_019.jpg

Ivatt_2T_020.jpg


Dave.
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Mike Garwood
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Re: Ivatt Class 2 2-6-2 tank

Postby Mike Garwood » Mon Jun 17, 2019 7:02 pm

Dave
Great work, really impressive. I don't know if you've been asked this before, but what do you use for rivets on the valve gear? The heads look way smaller than I've seen. What's the secret please?

Hope you're keeping well.

regards

Mike

Dave Holt
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Re: Ivatt Class 2 2-6-2 tank

Postby Dave Holt » Mon Jun 17, 2019 7:12 pm

Mike,
They're filed down brass lace makers pins. Just held in a pin-chuck and rotated over a file to reduce the diameter and then thinned down.
Dave.

Dave Holt
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Re: Ivatt Class 2 2-6-2 tank

Postby Dave Holt » Mon Jan 10, 2022 11:40 pm

This loco has been in abeyance sine June 2019, or so it seems. Obviously, a rebuilt Royal Scot thingy has got in the way, but that doesn't account for the whole period, so I'm not sure what else I have or haven't done in the mean time (could be a Black 5 involved?). Actually, the chassis has been completely stripped to component parts and degreased/cleaned ready for painting, currently in a tub.
Ivatt_2T_025.JPG

Today, I started to think about the body and have decided to stick with the Bachmann boiler, having flirted with the idea of replacing it with a spare DJH white metal example. Still not sure whether to replace the chimney or not. However, I did make a start on thinning down the plastic moulding round the cab openings and side windows using a scalpel blade applied with lots of care. OK so far.

Dave.
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DougN
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Re: Ivatt Class 2 2-6-2 tank

Postby DougN » Tue Jan 11, 2022 6:35 am

Dave, I wish I could get back to things so quickly!!! only 3 years I have restarted a J26 from 2015 again. Looks like it may get completed.. I am working on the Locomotive body as the tender is complete just about ready for painting. The Chassis is all there but the "chunk" I have taken to finish is the loco body. I have things from 10+ years ago I am still trying to finish off. I appear to be getting better though as things are getting finishing now.

It is interesting to see that every one appears to have things started placed in a box and forgotten then restarted and completed years later. :thumb
Doug
Still not doing enough modelling

Dave Holt
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Re: Ivatt Class 2 2-6-2 tank

Postby Dave Holt » Thu Jan 13, 2022 9:02 pm

Yes, Doug, you're probably right. Mind you, for a long time I was very disciplined and didn't start a new loco till the previous one was finished. However, over the years I slipped down the slippery slope of having several on the go at once. I think my Jubilee was the most drawn out as it sat for about 10 years(ish) in a part completed state whilst several other projects overtook it. Did get there in the end.
The Bachmann Ivatt tank body is very good, dimensionally, but is a bit basic by modern RTR standards. One aspect which really can't be corrected without major work, such as etched overlays, is the lack of crisp corners to the moulding. This will very much have to be a layout loco to be viewed at a distance.
Besides the inevitable thick plastic moulding, visible at window and cab openings, one of the most glaring errors is that the cab doors are not recessed far enough and have poor, half-relief, hand rails and stanchions. This problem is shown in these photos.
Ivatt_2T_026.JPG

Ivatt_2T_027.JPG
.
The latter shot shows the rearmost window opening after thinning of the over-scale edges. The back edge of the cab opening has also been thinned down, but the front left as is, as the real locos had a sort of draught screen there.
To try to improve the cab door arrangement, I had some etched components made to better represent the recess and facilitate proper hand rail stanchions and rails. This requires the moulded door to be removed and the next shot shows the basic removal and the two new etched replacements.
Ivatt_2T_028.JPG

Quite a bit more filing required to let the etches fit into the opening. Just visible through the cab opening is the top edge of the frames, which gives an idea of the height of the new cab floor, yet to be made. The floor will carry front and rear bulkheads, firebox back-head, reverser, etc.
Dave.
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Dave Holt
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Re: Ivatt Class 2 2-6-2 tank

Postby Dave Holt » Wed Jan 19, 2022 11:11 am

The new recessed doorway has been prepared and loosely tried in position after filing the cab opening. I'm quite pleased with the fit I've achieved considering my filing of the plastic was a bit roughty-tuffty.
Probably ought to use a 5 minute epoxy to fix in positions as this will give a bit of adjustment time compared with an isocyanate superglue.
Ivatt_2T_029.JPG

Ivatt_2T_030.JPG

Let's hope the other side goes as well.
Dave.
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RAO
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Re: Ivatt Class 2 2-6-2 tank

Postby RAO » Wed Jan 19, 2022 11:32 am

If you require any photo's of the original locomotive, let me know.
There is an Ivatt 2-6-2T at Ropley MPD currently undergoing repairs.

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PeteT
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Re: Ivatt Class 2 2-6-2 tank

Postby PeteT » Wed Jan 19, 2022 7:07 pm

Looking good Dave, that door is going to make a massive improvement!

Mine has stayed similarly on the back burner for a while, but getting that ladder etch sorted is very near the top of the queue...


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