1P 0-4-4T chassis by Rumney

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Tim V
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Re: 1P 0-4-4T chassis by Rumney

Postby Tim V » Fri Feb 08, 2019 5:10 pm

How many times larger than life size are those pictures John?
Tim V

John Palmer
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Re: 1P 0-4-4T chassis by Rumney

Postby John Palmer » Sat Feb 09, 2019 3:41 pm

Tim, I estimate between 8X and 10X full size. :)

I have a question for Justin or Pete as to the queried dimension on this image:
2228 Bogie query.jpg
I take this to be the pitch of the CSB wire above the bogie wheel centre, and by scaling the drawing in the instructions into a CAD drawing showing the rudiments of a 2228 class engine, I have arrived at an estimate of 4.2 mm - is this correct?

The reason for my enquiry is that I am considering substituting eighth inch bore hornblocks for 2mm bore blocks on the bogie. The larger blocks should permit a double bushing arrangement, whereby a 2mm ID brass bush to carry the axle will be pressed into a one-eighth inch OD delrin insulating bush, which in turn will be pressed into a commercial hornblock. Potentially this looks like a reasonably straightforward way to combine a CSB suspension for the bogie with split axle current collection from the bogie wheels - the innermost brass bush can carry a feed wire to a bus on the bogie frame, whence a further plug connection to the main collector bus between the mainframes can be made.

Clearly this will involve attaching the CSB carrier tag to the commercial hornblock rather than the innermost brass bush - otherwise the axles/wheels will lose their insulation from the bogie frames. This approach will involve making four replacement CSB tags, which should be straightforward enough provided I know where the CSB spring is to be pitched, hence the enquiry.

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jjnewitt
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Re: 1P 0-4-4T chassis by Rumney

Postby jjnewitt » Sat Feb 09, 2019 6:22 pm

Hi John,

The cirtical dimension for the spring carriers on the 1P bogie is 4mm. This is the vertical distance from the axle centre to the bottom of the hole in the spring carrier onto which the spring wire bears. If you need to make new carriers then use this dimension.

Spring Carrier Dimension.JPG
Spring Carrier Dimension.JPG (29.53 KiB) Viewed 3082 times

Interesting idea. I'll look forward to seeing how you get on.

Justin

John Palmer
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Re: 1P 0-4-4T chassis by Rumney

Postby John Palmer » Sun Feb 10, 2019 1:33 am

Perfect, that's exactly the information I need. Adding the 4mm value to half the diameter of whatever drill I use should get the CSB wire to exactly the right pitch - thank you very much, Justin.

This is looking promising. I have taken an hour or so to machine six delrin bushes and found no difficulty in getting a wall thickness of .25mm, implying that there should be no problem in double bushing a one-eighth inch bore hornblock to produce a bearing with 2mm bore that is insulated from the rest of the chassis. I've made a batch of six because I am proposing a first test of this technique on the tender of a Brassmasters EasiChas kit for the Bachmann 3F. The suspension arrangement on the EasiChas kit is a little different from one having sliding brass hornblocks, but the insulation principle is the same.

For me the big plus point in the arrangement I am trialling is that it should simplify the process of isolating each half-wheelset from the rest of the chassis. No longer any need to insulate one mainframe from the other using gapped pcb or similar, and brake rigging can be a metal-to-metal connection across the frames - no longer any need to find a way of insulating one side of the brake rigging from the other. It's possible to do that by clipping the brake gear onto machined delrin mounts let into the frames, but I think what I am suggesting should be simpler.

I hope to be able to report a successful outcome in due course.

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MarkS
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Re: 1P 0-4-4T chassis by Rumney

Postby MarkS » Mon Feb 11, 2019 2:04 am

John, you are causing me to take another look at my model, and the list of 'failing-to-live-up-to-the-chassis' grows...

    The interior part of the tank needs to be cut back. (in the instructions...)
    Replace the brake handle LHS (bloated white metal thing, gets replaced with cut back tanks)
    Build and add screw reverser in cab RHS (noticeable in photos, especially with the tanks cut back...)
    Replace smokebox door and ring (Not sure if it bothers me enough, yet...)
    Replace tank filler caps (not sure what Craftsman was thinking...)
    Add rounded buffer beam ends (small scraps of plasticard)
    Add coal door back end to cab interior (what does this look like?)

I have not found a drawing or photo showing the coal door / back of the cab. was it flush or cut out like the kit?

BTW, thanks for the triple romans picture, was this a case of "double Romans look fine, but I can do one better"? :D
Cheers,

Mark.
"In the end, when all is said and done, more will have been said than done..."

John Palmer
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Re: 1P 0-4-4T chassis by Rumney

Postby John Palmer » Mon Feb 11, 2019 12:17 pm

Mark, if you don't already have it I highly recommend you to lay your hands on a copy of Wild Swan's 'Midland Engines No.1' profile, which covers the 1833 and 2228 class bogie tanks. Your 1823 class engine is substantially identical to the 1833s, the difference being the raising of boiler pressure from 140 to 150psi on the latter. How I wish this profile had been available to me when I embarked on my 2228 class engine!

I can imagine your reluctance to do anything that might affect that lovely paint job on 1350, as I am nerving myself to apply paint stripper to my model of 58086, lining and all, preparatory to an extensive rebuild to go with the new chassis. I don't have too many qualms about this, however, because it was the only engine of mine to receive Pressfix rather than Methfix transfers/lining, and I'm dissatisfied with the Pressfix transfers because they visibly stand proud of the panels to which they have been applied.

I can help a bit with the bunker configuration. I believe that enormous cutout in the Craftsman etchings was necessary to accommodate the magnet of the X04 motor for which the chassis was designed, so that would certainly benefit from being altered to a more accurate representation of the prototype. From the GA drawings reproduced in the Wild Swan profile I have developed some sketches (not to scale as reproduced here) of what I take to be the correct shape and dimensions of the bunker on an 1833 class engine:
1833 Class Johnson 0-4-4T bunker plan view.jpg
I've never yet seen a picture showing the empty bunker of a bogie tank from above, but the GA drawing does indicate that the bunker space had side tanks of the same height as the main side tanks. If the engine is fully coaled their presence becomes academic anyway.

The coal outlet cutout on the front plate of the bunker (i.e. within the cab) rose to 16.5” above floor level and was just under 27” wide, but apparently offset somewhat so that its left hand edge was 15.5” distant from the bunker centreline as viewed from within the cab and looking towards the rear of the locomotive. The aperture was closed off by means of a plate sliding vertically between guides rising to 30” above floor level.

Note that the centre part of the bunker front projects forward relative to the outer sidesheets, as the attached sketches show. I don't think I can have figured that out by the time I came to address the matter on my Craftsman kit, so in this respect my model of 58047 is wrong. Above the cutout in the front plate and extending the full width of the bunker between the tanks was a locker covered by a hinged lid. The GA drawing shows that the lower back corner of this locker space was radiused, presumably to assist coal dropping down onto the shovelling plate.

A replacement brake handle is a nice, straightforward exercise if your cab roof can be removed, and tank fillers shouldn't be difficult to replace either, if you can find suitable replacements (I couldn't see an alternative to turning my own). Possibly Craftsman's filler was intended to represent those found on the condensing engines, but why?!

Anyway, hope these ramblings may be of some help.

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PeteT
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Re: 1P 0-4-4T chassis by Rumney

Postby PeteT » Mon Feb 11, 2019 8:07 pm

Thanks for sharing that John, and for my 2 penneth please continue rambling away!

The other thing to note in the cab is the raised floor from just inside the cab doorway which is 3.5 inches high. This will be useful to give some trunking for my decoder wiring, as that is living in the bunker - keeping room elsewhere for weight - and helps keep the wiring out of the way from interfering with the chassis and/or becoming visible.

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MarkS
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Re: 1P 0-4-4T chassis by Rumney

Postby MarkS » Mon Feb 18, 2019 11:20 pm

Thank you John for the bunker configuration, Now I can finish the cab interior to a reasonable standard.
I don't have Midland Engines No. 1, but I do have many photos, and three sets of drawings. What I didn't have was photos or drawings of the back of the cab!

I will get to the body work later since the original thread is about the chassis - of which, progress continues.

First off, the brake gear, I soldered the the brake blocks to the lower cross wire, spaced to fit the wheel treads and added short lengths at the top.
Then, using the holes in the chassis as a jig, I soldered on the brake rods. (very carefully!)
Then I opened up the brake hanger holes to take short 1mm OD tubes and soldered them to the chassis. (The tubes cannot go through the chassis because the CSB wires are in the way.)
The result is that the brake gear is removable for maintenance, painting etc. (The rear cranks will be soldered on later and will have pins to go into the main brake pivot tube.
P1050812.JPG

On the kit, the ashpan seems to go too far back, and I thought that it was unlikely the main brake pivot rod went through the ash pan as this photo shows. (Note: the brake piston can be horizontal or vertical)
P1050820.JPG
P1050820.JPG (216.19 KiB) Viewed 2684 times

So I shortened the ash pan on the model accordingly and soldered in more 1mm OD tube...
P1050813.JPG

This is where I am currently, I really like the ability to separate the chassis into its component parts. I actually look forward to painting this chassis! BTW, the white piece of 40 thou. plasticard is the cab floor.
P1050818.JPG


Next up: electrical pick up and side control springs for the bogie. Don't hold yer breath...
Cheers,

Mark.
"In the end, when all is said and done, more will have been said than done..."

John Palmer
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Re: 1P 0-4-4T chassis by Rumney

Postby John Palmer » Wed Feb 20, 2019 11:39 am

MarkS wrote:On the kit, the ashpan seems to go too far back, and I thought that it was unlikely the main brake pivot rod went through the ash pan as this photo shows. (Note: the brake piston can be horizontal or vertical)

A word of warning: unless you have a photograph proving me wrong (entirely possible!), I think you'll find that only the 2228 class had their brake cylinders mounted vertically.

I conjecture that the diagonal bar visible directly below the brake cylinder in your picture forms part of a cradle to support the ashpan and may have been an in-service modification, as I can't see it in the GA drawings contained in the Wild Swan profile. Perhaps they had some failures of the lug and cotter arrangement by which I assume the ashpan was held up, and this cradle was applied to engines thought to be at risk of dropping the whole caboodle into the four foot. It doesn't seem to have been applied to all engines, but wasn't uncommon.

Further below-footplate details you might want to consider are:

1. The front damper operating lever along the left side of the ash pan (can't understand why the Midland didn't fit a back damper, given the amount of bunker-first running to be expected of these locomotives)
2. The brake release spring. This measured about 10-12" in length by about 6" in diameter. It was connected to the front of one of the r/h brake hangers above the brake block pivot and pulled into compression by application of the brakes. Most of these bogie tank designs feature a sandbox ahead of the trailing driving wheel, and on these the release spring was attached to the leading hanger. On my 58047 this space was occupied by a sandbox, so this engine has the release spring attached instead to the trailing driving wheel's brake hanger.

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PeteT
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Re: 1P 0-4-4T chassis by Rumney

Postby PeteT » Wed Feb 20, 2019 6:57 pm

Hi Mark,

Thanks for posting that photo - very clear on that how the ashpan sits. It is the one downside of the Wild Swan books, GAs are not always that clear (to me at least!) and while some detailed photos are included these are not all emcompassing!

Typically, I had just got around (last week) to accepting that the pivot points must be separate each side - which doesnt sound mechanically good, but I expect could be kind of balanced - and had put the ashpan wrapper as per the instructions, and cut my cross tube! At least it was then just waiting for all the other sub structures to progress towards the paintshops, so while it means unsoldering and fettling a few bits I will at least get it right without stripping and repainting to worry about.

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MarkS
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Re: 1P 0-4-4T chassis by Rumney

Postby MarkS » Wed Feb 20, 2019 11:21 pm

Hi Pete, John
I get it, sometimes it can be a case of solder it on, solder it off, solder it on... repeat.
The nice thing about substructures is that shortening the ash pan was easy - there was no chassis in the way.
Glad the photo helped. BTW, it is of LMS 1272, which was motor fitted.
Could the diagonal piece be part of the motor fitted gear?

As to the vertical brake piston, the photos I have shows it on LMS 1397 & 58091/LMS 1430 (both of the same series), I mentioned it because there are both type of brake lever on the etch...

I'm lucky I have a clear photo of the RHS of 1350 in front of those Triple Romans on the Mess room. ("Burnham to Evercreech Junc." Mitchell & Smith)
It also shows clearly what the rear lamp irons look like.

I'll take a look for a damper lever, but I suspect the release spring may be a 'detail too far'... :)
Cheers,

Mark.
"In the end, when all is said and done, more will have been said than done..."

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PeteT
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Re: 1P 0-4-4T chassis by Rumney

Postby PeteT » Thu Feb 21, 2019 9:26 pm

Hi Mark,

Interesting that it is 1272 - there are some very useful photos of that one in Midland Record Preview Issue (taken by AE West) so maybe more of his work? One of them is the best view I have of the cab of a Belpaire boiler fitted loco, though still not ideal from a backhead point of view. I think between it and the photo in An Illustrated Review of Midland Locomotives Volume 1 (Essery & Jenkinson) on page 87. This shows 1 of the gas fitted compounds - but the screw reverser, regulator, gauge glasses and most other fittings look like they havent been altered - just an extra pipe into the firebox!

All sketches in the GA of the ashpan, both from the side and above, do show the ashpan as enveloping the brake shaft - a good reminder that what is drawn and what is built are not always one and the same...

20190221_205722.jpg


Edited to add that my ashpan has now been dismantled, so now just need modifying and reassembling!

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MarkS
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Re: 1P 0-4-4T chassis by Rumney

Postby MarkS » Fri Feb 22, 2019 8:36 pm

Hi Pete,

the photo of 1272 is from "An Illustrated History of LMS Locomotives Vol. 4" - Essery & Jenkinson, so very likely the from the same source.

Looking at GA it certainly gives the impression that the ashpan envelopes the brake shaft but what a pain that would be to build and maintain.
The photo shows that they seem to have come to their senses.
Cheers,

Mark.
"In the end, when all is said and done, more will have been said than done..."

John Palmer
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Re: 1P 0-4-4T chassis by Rumney

Postby John Palmer » Sat Feb 23, 2019 12:42 pm

On the attached drawing extract I've marked in red my take on the cross-section of the ashpan that was originally intended, and in green the version finally adopted. Following my previous comment on the absence of a back damper, closer examination of the GA drawing also tells to me that the draughtsman originally intended the locomotives to be equipped with these, the location and operating mechanism for which I've shown in blue.
Bogie tank ashpan speculative cross sections.jpg

Fabrication of the original design doesn't look hard, and removal of the ashpan is straightforward enough as you can lower the back end onto the brake cross-shaft before drawing it forward enough for it to drop to the ground.

For whatever reason, a decision seems to have been taken to do without the back dampers, in the absence of which the 'bathtub'-like cross-section indicated in green replaced the original shape. Perhaps someone pointed out to the draughtsman that those square-cornered nooks and crannies at the back end of the original design were going to be a good place for deposits of wet ash to accumulate and remain, since their removal with fire irons was going to be problematic, and that this was going to lead to the back corners of the pan rotting away in short order. Perhaps this was instrumental in a decision not to fit back dampers.

The 'bathtub' shape finally adopted is MUCH easier to rake clear, but required more in the way of panel beating skills in its initial manufacture. Some of that final shape is pure conjecture on my part; it would be interesting to see drawing 91/3537 for the details.

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MarkS
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Re: 1P 0-4-4T chassis by Rumney

Postby MarkS » Sun Aug 25, 2019 11:39 pm

So after months of thinking about what I might do with this loco, I pulled out the fret saw and cut the tanks back and installed a cab interior. It was a bit like building a ship in a bottle, but it saved me from a complete re-paint.
I mostly fabricated the interior from plasticard and bits, with a backhead from gibson I believe, with added detail.
All very impressionistic, but with a driver and fireman, it will look the part.
P1050932.JPG


I also fabricated new water filler caps, finally finding a purpose for some old Ratio buffer heads...
P1050933.JPG

Some final touch ups and weathering to be done, and a chassis to finish...
More to follow, don't hold yer breath!
Cheers,

Mark.
"In the end, when all is said and done, more will have been said than done..."

John Palmer
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Re: 1P 0-4-4T chassis by Rumney

Postby John Palmer » Mon Aug 26, 2019 1:39 am

Really good work to have accomplished those changes without upsetting all the previous, equally good work on the painting and lining - congratulations! The first thing that caught my eye was the dramatic improvement of those tank fillers.

I've just discovered that my 2228 class engine's failure at Scaleforum 2018 was due to wearing out of the brushes in its Sagami can. The carbon on one brush had completely worn away, leaving only its carrier spring bearing on the commutator. Following failure of the previous motor on the Saturday of a Railwells to which we had taken the Burnham layout back in the 1980's, this can was installed as an overnight emergency repair. Held in place with sticky tape, so well did this lash-up perform that it remained unchanged for the next 30 years! I fear, however, that I shall now have to postpone its rebuilding with new etched chassis because I have to give priority to my role as Chief Property Developer for the Burnham townscape.


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