Ivatt 2 2-6-2T

User avatar
PeteT
Posts: 375
Joined: Tue Jan 11, 2011 9:53 pm

Ivatt 2 2-6-2T

Postby PeteT » Mon Feb 11, 2019 7:36 pm

So some of this build has already been covered in https://www.scalefour.org/forum/viewtopic.php?f=135&t=5186, but picking up the topic in its own thread will save it meandering around quite as much as my workbench does!

So from where it was left in that topic, as an 0-6-0 with coupling rods and no valvegear it rolled round perfectly. The valvegear is as per the Comet kit, except for using a DJH crosshead. I'm not convinced by the etched valve spindle guides, and need to tap the return crank for the crankpin, and will then be in a position to get the 0-6-0 working well again but with valvegear. This is behind finishing the 1P in the priority list though...

20190128_202022.jpg


However, alongside the etches for the 1P arrived an etch to convert the Brassmasters sprung LMS pony truck to the swing link version. Dave Holt was kind enough to share with me the sketch of how he did his, and I converted this into a concept for a fold up and pinned assembly for etching.

20190206_103947.jpg


So this is the section from the Brassmasters assembly which needs removing. Ultimately it needs removing from front and rear of the truck, and 2 replacement assemblies will be required per pony.

20190210_220254.jpg


Starting to fold it up, the bottom section needs folding in a certain order to prevent collisions as it comes together...

20190210_220239.jpg
20190210_220239.jpg (249.27 KiB) Viewed 4229 times


Then the links are aligned and pinned through.

20190210_220311.jpg


As drawn, I had designed it to replace the entire front of the Brassmasters unit, as the links have 2 holes in the top which are pinned - however it actually makes the assembly process more straight forward to just utilise the central section as this slots home nicely into the gap left in the middle of the pony truck (I also got the width of the top fold over section wrong, not quite sure how as the bottom dimension was drawn correctly).

20190210_220217.jpg
20190210_220217.jpg (100.3 KiB) Viewed 4231 times


I do need to tweek the artwork slightly (and try and take a replacement photo which doesnt come out so grainy!), but am very happy with the way it folded up and slotted in painlessly, and I think looks the part.

This type was used on the front of Ivatt 2 tanks, the rear of Standard 2 tanks, and on Ivatt 2 2-6-0s (at least, possibly standard 3 (and an outside chance for the class 4) tanks too? The same type wasn't used on earlier LMS tanks including the Fairburns though).

Dave Holt
Posts: 258
Joined: Thu May 28, 2009 9:44 pm

Re: Ivatt 2 2-6-2T

Postby Dave Holt » Mon Feb 11, 2019 7:47 pm

Pete,
Your etch looks just the job, even if it needs a bit of a tweak to get the bends right. Wish it had been available when i was doing my trucks!
Regarding where else the swing link was used, it was just the rear truck of the Std 3 tank. All the locos with just one truck used the spring side control design. The only reason for different trucks on the 2-6-2 tanks was to guarantee a different natural frequency at the two ends, to prevent oscillations becoming additive. Obviously, this problem couldn't arise with just one truck or a truck and a bogie.
looking forward to seeing further progress, in due course.
Dave.

User avatar
PeteT
Posts: 375
Joined: Tue Jan 11, 2011 9:53 pm

Re: Ivatt 2 2-6-2T

Postby PeteT » Wed Feb 13, 2019 7:55 pm

Thanks Dave,

Yes, I thought that was probably the case with the standards. I understood/understand why the front and rear are different, but I don't think I've found out why BR swapped the front and back - though I suppose with the coupled wheelbase and distances from outer driven wheels to pony wheels - as well as the way weight is distibuted along the loco - it will make a difference to how they operate.

I'm not quite sure how many I will end up assembling, but certainly enough to make it a worthwhile etch - and if it helps anyone else along the way then alls the better!

Thanks,
Pete

IANATEXTON
Posts: 49
Joined: Sun Feb 20, 2011 10:12 pm

Re: Ivatt 2 2-6-2T

Postby IANATEXTON » Wed Feb 13, 2019 10:30 pm

Pete,
I have a Kemilway BR Standard Class 3 tank to build, so I would be interested if you are making the etch available. I already purchased 2 of the Brassmasters pony truck etches, but I didn't realise that the pony trucks weren't identical until I read Dave's thread on his brilliant BR Standard class 2 tank.
Ian

User avatar
Horsetan
Posts: 1117
Joined: Tue Jul 29, 2008 9:24 am

Re: Ivatt 2 2-6-2T

Postby Horsetan » Wed Feb 13, 2019 11:31 pm

IANATEXTON wrote:Pete,
I have a Kemilway BR Standard Class 3 tank to build, so I would be interested if you are making the etch available. ...


Ditto, though my Class 3 is the PDK/ex-Crownline kit.
That would be an ecumenical matter.

User avatar
PeteT
Posts: 375
Joined: Tue Jan 11, 2011 9:53 pm

Re: Ivatt 2 2-6-2T

Postby PeteT » Thu Feb 14, 2019 8:44 am

Hi Ian, Ivan,

Same, Dave has a lot to answer for ;) ! There are some things, pony trucks being a good case in point, that in a lot of photos they are hidden in shadows - but once you have seen them and seen the differences they do jump out.

Yes, I have the Brassmasters hornblock CSB adapters already available via Justin at Rumney Models, so I plan for the same with these. The only caveat is that I know Justin has removed a few of the smaller items from the catalogue (not enough sales to warrant a full sheet to themselves, which then makes stock control difficult to balance with the other items they share a tool with) but I'm sure we can work something out.

Any further expressions of interest would only help their case!

Thanks,
Pete

User avatar
Mike Garwood
Posts: 573
Joined: Sun Aug 03, 2008 4:51 pm

Re: Ivatt 2 2-6-2T

Postby Mike Garwood » Thu Feb 14, 2019 9:04 am

Pete

Count me in ; Std 3 and 4 in the to do pile.

Mike

Dave Holt
Posts: 258
Joined: Thu May 28, 2009 9:44 pm

Re: Ivatt 2 2-6-2T

Postby Dave Holt » Thu Feb 14, 2019 11:57 am

Mike Garwood wrote:Pete

Count me in ; Std 3 and 4 in the to do pile.

Mike


Don't need one for the 4, Mike. See my earlier comment.
Dave.

User avatar
barrowroad
Posts: 164
Joined: Sun Jul 20, 2008 5:28 pm

Re: Ivatt 2 2-6-2T

Postby barrowroad » Thu Feb 14, 2019 7:05 pm

Hi Pete,
Put me down for one for my Kemilway Class 3mt

Robin

Andrew Ullyott
Posts: 174
Joined: Fri Aug 08, 2008 2:31 pm

Re: Ivatt 2 2-6-2T

Postby Andrew Ullyott » Thu Feb 14, 2019 8:22 pm

Hi Pete
Another one for a Kemilway class 3 please!
I assume it was your comment earlier on my RMWeb blog?!

User avatar
PeteT
Posts: 375
Joined: Tue Jan 11, 2011 9:53 pm

Re: Ivatt 2 2-6-2T

Postby PeteT » Thu Feb 14, 2019 10:02 pm

Thanks All, sounds like it will be viable then!

Yes Andrew, I've just replied :)

Here is a slightly better photo, though to be fair at several times lifesize it is always going to look a tad rough...

20190214_204138.jpg

Jeremy Good
Posts: 130
Joined: Fri Feb 19, 2010 10:36 pm

Re: Ivatt 2 2-6-2T

Postby Jeremy Good » Thu Feb 14, 2019 11:07 pm

Pete

Can you add me to the list for one for a 2MT as well please?

Thank you

Jeremy

User avatar
BryanJohnson
Posts: 111
Joined: Wed Jul 23, 2008 7:45 pm

Re: Ivatt 2 2-6-2T

Postby BryanJohnson » Fri Feb 15, 2019 11:33 am

Hi Pete,

Another one for a BR 2MT please.

Many thanks,

Bryan

User avatar
PeteT
Posts: 375
Joined: Tue Jan 11, 2011 9:53 pm

Re: Ivatt 2 2-6-2T

Postby PeteT » Thu May 09, 2019 8:30 pm

Thanks for all the interest!

I've got the 2nd test etch back. I changed tack slightly for this version, in effectively bridging between the front & back parts. This allows, on the Brassmasters truck, for the top piece to be substituted completely - but it may also make life easier if the starting point is a different pony (Comet, DJH, etc). The theory, as last time, is that it should all fold up in one, and then pin the swing links in place.

20190509_140532.jpg


It soon became apparent though that the slot next to the top piece isn't wide enough to fold/roll the assembly through. However, while it removes the middle section, keeping two outer arms allows the folds to happen, and keeps the front & rear assemblies the right distance apart.

20190509_140450.jpg


20190509_140350.jpg
20190509_140350.jpg (244.97 KiB) Viewed 3410 times


20190509_140255.jpg
20190509_140255.jpg (229.54 KiB) Viewed 3410 times


20190509_210405.jpg


So, the slight geometrical issue in rev 1 has been corrected. I personally like the whole thing being as 1, and a solid top could still be etched to pin back on top of this assembly - allowing for a rubbing plate, secondary spring system, etc to be implemented. Does this approach sound sensible to everyone else?
Attachments
20190509_140409.jpg
20190509_140330.jpg
20190509_140330.jpg (93.19 KiB) Viewed 3410 times
20190509_140312.jpg
20190509_140312.jpg (147.76 KiB) Viewed 3410 times

User avatar
PeteT
Posts: 375
Joined: Tue Jan 11, 2011 9:53 pm

Re: Ivatt 2 2-6-2T

Postby PeteT » Sun Dec 15, 2019 5:43 pm

A couple of tweaks to the swing link pony etch, to allow it to fold up around itself ok. I have allowed anchor points for crossways spring wires, so need to form these and test the assembly - but the cosmetic bit looks the part.

20191204_192653.jpg


20191215_171830.jpg


20191215_171843.jpg


20191215_171858.jpg


20191215_171912.jpg


20191215_171925.jpg


20191215_171948.jpg


20191215_172010.jpg


I have also had attempt 1 of the bunker ladder etched. This has proved to be a bit narrow - not helped by a slightly over etched test sheet, but the design didn't help itself so beefing it up slightly will help. I also since had discussions about assembly jigs for some ladder etches which use this concept - and a separate jig rather than the built in cross braces which then need removing and tidying up may make life easier.

The intermediate body fixings fell off due to the width and over etching - but otherwise it did at least go together so is a good starting point for version 2!

20191204_192649.jpg


20191215_171808.jpg


20191213_161505.jpg


20191213_161536.jpg


20191213_161550.jpg

Dave Holt
Posts: 258
Joined: Thu May 28, 2009 9:44 pm

Re: Ivatt 2 2-6-2T

Postby Dave Holt » Mon Dec 16, 2019 11:06 am

Peter,
This looks to be coming along very nicely. The pony truck frame replicates the appearance of the real thing very well indeed. How does the remaining, un-folded part, which has been added since the earlier version, work? The ladder does look to need beefing up a bit but has great potential, so I'm looking forward to seeing your next iteration.
Dave.

User avatar
PeteT
Posts: 375
Joined: Tue Jan 11, 2011 9:53 pm

Re: Ivatt 2 2-6-2T

Postby PeteT » Tue Dec 17, 2019 8:07 pm

Thanks Dave,

The main purpose of the remaining part is to form the top - the failing of the version 2 etch was the need for it to fold up through the middle.

The two fold down ears though are hopefully of use for springing. They are in board so as to sit inside the Brassmasters hornguides, and I know in the clag article the coil is in the top corner of the hornguide, whether it would work inset by this amount - and whether it makes life any easier - remains to be seen. I hope to have a go at this before Christmas, but time is passing rapidly!

For completeness for anyone who hasn't seen the pony springing concept it is covered on http://www.clag.org.uk/comet-pony.html

Thanks for the ladder comments! :)

Dave Holt
Posts: 258
Joined: Thu May 28, 2009 9:44 pm

Re: Ivatt 2 2-6-2T

Postby Dave Holt » Tue Dec 17, 2019 8:21 pm

Yes, the CLAG explanation is actually my method of springing these open frame trucks which I passed to them some years ago. I put the coils in the top corner to give more spring length and ease of attaching the upright leg in the corner of the frame. Actually, the ideal position would be level with the top of the axle but might be a bit hard to judge and get both sides roughly equal.
Dave.

User avatar
PeteT
Posts: 375
Joined: Tue Jan 11, 2011 9:53 pm

Re: Ivatt 2 2-6-2T

Postby PeteT » Sat Dec 21, 2019 10:40 am

Yes I know your name was attached to the CLAG write up. As you say, my concern with moving it inside of the hornguides is reducing the spring length - but if it makes it easier to set up and equal between the two arms it may be a worthwhile tradeoff.

I am hoping to make time this afternoon to assess this...

User avatar
PeteT
Posts: 375
Joined: Tue Jan 11, 2011 9:53 pm

Re: Ivatt 2 2-6-2T

Postby PeteT » Fri Jan 24, 2020 6:15 pm

Hopefully the following images show the concept of the spring ears a bit more clearly - a little jig to get the length and angle of the V to locate over the axle the same between the pair - and with fitting in an open assembly it should be easier to set up equally.

This may still all fall flat on its face if the shorter run doesnt work, or there isnt the clearance for the coils next to the axle. I have started assembling the main Brassmasters frame, and have a rare weekend at home, so will hopefully find out soon!

The first three photos are with the basic frame assembled, the fourth has the equaliser arms and pivot rod fitted. With hindsight, these would be better fitted before the springs, to save deforming them or even just stop them getting in the way.

20200121_200158.jpg


20200121_200217.jpg
20200121_200217.jpg (228.86 KiB) Viewed 1739 times


20200121_200247.jpg


20200124_180336.jpg


20200124_180427.jpg

User avatar
PeteT
Posts: 375
Joined: Tue Jan 11, 2011 9:53 pm

Re: Ivatt 2 2-6-2T

Postby PeteT » Sun Jan 26, 2020 11:39 am

Now fully assembled, I think the springing is about the same as the previous test build which used Dave's original spring coil locations tucked into the top corners of the hornguides - but for me was easier to assemble and balance. Therefore I will include the fold down tabs for these, which will allow anyone else to make up their own mind as to whether to fold down & use these attachment points or not.

20200126_114210.jpg


20200126_113100.jpg


Edited to add 2nd (1st) photo

User avatar
PeteT
Posts: 375
Joined: Tue Jan 11, 2011 9:53 pm

Re: Ivatt 2 2-6-2T

Postby PeteT » Fri Mar 20, 2020 7:03 pm

I hope everyone is doing ok - I haven't yet seen an increase in modelling time, but it is now the weekend - I can't go to Porthmadog, and the pubs are shut - so the modelling bench calls! However, that should mean time spent detailing the 1P, not on this.

However, the reason for a quick update to this topic is to note (for those who haven't already noticed directly) that the pony swing link etch has now been released, and is available via Justin at Rumney models (alongside some other interesting looking bits & pieces):

viewtopic.php?f=30&t=2697&start=75

http://website.rumneymodels.co.uk/latest-releases


Return to “PeteT”

Who is online

Users browsing this forum: No registered users and 2 guests