Mickoo's BR modelling

mickoo

Western Thunderer
Well lets start with the class 40 this evening, sure enough there's not enugh rake on the windscreen, by a rough guess 1 - 1.5 mm.

It doesn't bother me enough yet (and may never do) but an option might be to use a thin slitting disc in a dremel and take a slice out and tilt the screen back. I think that might be preferable to trying to sand the screen back to a higher rake and keep the three faces flat and true.

Interestingly, the noses are all the same length, I'd have wagered the 40 was longer but I'm not quite sure which model has the correct sized bonnet doors, class 40, JLTRT 37 or Heljan 37 1st tooling.

Some highly scientific shots to show the difference.

IMG_3412.JPEG

IMG_3413.JPEG
 

timbowales

Western Thunderer
I'm actually not surprised that the noses are the same. From an engineering and production point of view it makes sense to maximise the use of standardised components. Swindon were doing it very successfully for years, until Collett came along :))
 

mickoo

Western Thunderer
Now the 37 frames and fuel tanks, lots going on here, primarily due to a moving goal posts depending on which model you're making them for.

Before going further it's probably best to try and explain why I'm doing all this, I did write that earlier but several people off grid told me I was wasting my time, I did explain I'd written what the loose scheme of things was in my head....ohh I don't read the words, just look at the pictures :rolleyes:

So in pictorial form it's here......


And here.


I've not decided which as yet, I never did Crimpsall but 10 shop I visited lots of times, just depends which new builds other stock I want to portray and which dates etc.

For the working models then a MPD somewhere is the plan; all pie in the sky no doubt, but dreams are free.
 

mickoo

Western Thunderer
Right class 37 tanks, first thing was to get a new chassis plate in so out with the Proxxon table saw, change of blade to monster eating metal one and carve off a big slab of 1.5 mm brass sheet. I've used the Heljan floor fixing screws and added long bolts in, by winding in and out I can level the floor where it needs to be.

IMG_3406.JPEG

The next item was the engine room floor block, this is screwed ( sub surface on the final run) to the brass chassis, it has a big hole in the middle, as will the brass plate so I can add the depressed engine section in as a 3D print when viewed from above. The primary object here is to get all the ribs, tanks and supports in the right places as well as the sand boxes.

I also need to remove the recessed plastic right that holds the skirts on the first tooling.....ro do I (more later). Once that ridge is removed then the ribs wiull be pulled out to the correct width and overlap the remaining shell edge.

It's not looking too bad and I need to cross reference the ribs with the bodyside features.....and here's where the :shit: hits the fan, all three models are different :headbang:

IMG_3407.JPEG

It should be noted that the tanks are not identical lengths, the diesel tank is longer, they're not bowed on the model, that's just the wide angle lens on the camera., the biggest concern is the position of the sand boxes, the tanks are in the right place (the outer brackets are eqi distance from the buffer beams) and that defines where the sand boxes go, but on the real engines the fillers are almost directly over the outlets.....but! I need to cross reference it all with the SRPS detail photos to be sure.

Either way the RH one looks miles out, as do the RH steps, filler hatch ang grills. The three grills is a known 1st tooling issue, they're actually a fraction too long, Heljan corrected this on the second tooling but then made them a fraction too short. The longer grills are clearly pushing the access steps and filler hatch out as well, not really a lot you can do abut that.

At this point the JLTRT model was pulled out and a direct comparison made.

IMG_3409.JPEG

Yup RH sand filler hatch is bleedin miles out, note also water filler hatch moved left and lower step also, that's all good and dandy, however the three grills are in the wrong place, they're the right length but too far left, the LH edge should line up with the cant rail edge above and the RH edge should extend just past the cant rail grill support, ideally all three need moving right 1.0 mm and they'd be perfect.

For giggles I stacked the second tooling on top.

IMG_3410.JPEG

Good news, the sand filler is now in the right place but note the short triple grill set, the LH edge is perfect but the RH edge is also level with the cant rail support, it should extend slightly past. They have also moved the lower water filler access step into the right location.

I used the JLTRT real thing tanks to work from when drawing up the replacement 3D ones, they're pretty accurate but I think the fuel tank is a smidge too long, the brackets are each end are identical but on the JLTRT one the #1 end has been truncated a bit as well as the inter tank bracket not being assembled correctly on the model, it's about 50/50 root cause as to why the JLTRT one extends further.

IMG_3411.JPEG

Anyway, using the JLRTR tanks as abasis the first ones I printed were woefully narrow on the Heljan first tooling. I figured it was down to the JLTRT thicker cill or side material, how incorrect was that!

To compensate I widened the 3D tanks by 2 mm and the side lined up perfectly with the sides on the shell, brilliant, everything sorted then, not so. The above photo shows that both sets of tanks when viewed directly below have the same sort mof relation ship with the body behind, the side walls were the same thickness, the kick in of the cills the same so why was the Heljan one 2 mm wider.

Then I measured the bodies overall width, yes you guessed it, the Heljan first toolling is wider, not just abit but rather a lot (relative), 1.5 mm to be precise. The extra 0.5 mm I added was just counteracting the material thickness at the base of the cill.

I measured the second tooling and found it to be the same as the JLTRT, so, for future tank packs I need to do two sets, one for the correct second tooling and a wider set for the fisrt tooling.

Summary, if you're going to expose the tank suppoorts and engine chassis in a workshop type repair scenario then the best option is the Heljan second tooling.

The next step is to decide which workshop and then work out which body support stands they used, 3D some of those up and start making holes in the body to daylight the areas I want to detail out.

The first tooling body will get replacement metal skirts fitted back on, I'll probably ditch the engine room 3DP chassis and ribs etc, drop the floor down and just bolt the tanks to the brass bit, or maybe a facsimilie of the underside like JLTRT; then work out how to get some bogies and power it, probably as a dummy in MU with another.

The JLTRT needs some work as well, bought fully built and powered one of the cabs is not straight and there are some ugly joints that need tending to as well as the chassis sitting high at one end (due to the misplaced cab no doubt), it's also still got a boiler and steps so not a refurb but the buffer shrouds have been cut back and headcodes plated over (all give away refurb signs). My gut feeling is that it's got the wrong noses on but I'll ave a trawl and see if I can find a boiler fitted 37 with plated headcodes and shrouds cut back, possibly one of the 37/4 (were they dual ETH and boiler?) large logos in Scotland in the early 80's. That would be grand as I do like them and traveled on them on several trips.

Onward.
 
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mickoo

Western Thunderer
I'm actually not surprised that the noses are the same. From an engineering and production point of view it makes sense to maximise the use of standardised components. Swindon were doing it very successfully for years, until Collett came along :))
I agree, but if you write on social media they're all the same you're bound to get hammered for it, hence hedging my bets unless I know for sure, in this case I didn't ;)
 

Eastsidepilot

Western Thunderer
Well lets start with the class 40 this evening, sure enough there's not enugh rake on the windscreen, by a rough guess 1 - 1.5 mm.

It doesn't bother me enough yet (and may never do) but an option might be to use a thin slitting disc in a dremel and take a slice out and tilt the screen back. I think that might be preferable to trying to sand the screen back to a higher rake and keep the three faces flat and true.

Interestingly, the noses are all the same length, I'd have wagered the 40 was longer but I'm not quite sure which model has the correct sized bonnet doors, class 40, JLTRT 37 or Heljan 37 1st tooling.

Some highly scientific shots to show the difference.

View attachment 233408

View attachment 233409
.....and a mil under gauge :)) .....got me coat !

Col.
 

mickoo

Western Thunderer
There are several 3D bogies kicking around EE Co Co is one, Western and 47 are others, they’re good but not optimized to get the best as a 3D print (my own personal perspective). There’s also several 3D engine blocks out there as well and suffer the same attributes. All good and well if you’re happy to sand smooth layer lines and artifacts.

But that’s my personal view, others mileage/satisfaction will vary :thumbs:

Having said that and viewed the above on the big PC, that's one of the better/best prints I've seen, which truth be told is inevitable as this aspect of the hobby advances. It's certainly a big improvement over their previous Western and 47 bogies.

FWIW 37, 50 and 55 bogies are all interchangeable and were swapped around, there are some detail differences to each type but the general mechanical structure and such like were pretty much the same.

That's a cast bogie for a Deltic but has steps for fitting to a class 37; I see one of the steps is already broken, that's the downside of 3DP and as discussed many times here, not everything is a nail.

There's not many configured like that kicking around, a 'very' quick check shows only 37 414 being a recipient of that set up, there will be others of course.
 
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Genghis

Western Thunderer
FWIW 37, 50 and 55 bogies are all interchangeable and were swapped around, there are some detail differences to each type but the general mechanical structure and such like were pretty much the same.
IIRC the bogies that were built for the 50's were swapped out with those from 37's for reasons I no longer remember.
 

mickoo

Western Thunderer
IIRC the bogies that were built for the 50's were swapped out with those from 37's for reasons I no longer remember.
The original Deltic bogies were fabricated and suffered cracks so took some of the class 37 cast ones.

The class 50 were cast from day one and stayed with the fleet as far as I can ascertain.

Initially the cast bogies were the same (37-50) with only one brake rigging guide bracket at the front end, later class 50's had a rear guide fitted (noted by the four bolt plate attached to the side of the casting) some 37's may have had that too but they may well be old class 50 bogies when they were scrapped, you'd need to check dates to be sure. I can't find any class 50 with fabricated bogies (as yet).....though that does not mean they never had them on occasion but I don't think it was the norm or common. My understanding was that the cast ones were prefered for the 100 mph machines.

Cast bogies with four bolt plates front and rear are late class 50's, single bolt plates at the front only are Deltics and early class 50 and whatever 37's had them fitted. As far as I can find pictorially, Deltics swapped out their bogies around 64-66, long before 50's were built. I've not sorted out yet which batches of 37 had the cast bogies from new or engines fitted in my date span (79-84), the tanks is a big enough headache to be getting on with.

Interestingly, the Deltics never had the brake rigging bracket fitted (that seems to only appear on the 37's and 50's) just a blank mounting pad. The same applies to the class 50 on the LMR, the bracket appears to have been fitted when on the WR around 73-75ish and then followed by the rear one some time later.

There are plenty of EE bogie anoraks out there and the topic has been done many times on RMWeb in depth.
 
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