Building and completing my 4mm 3D Printed GNR Coaches

[PGN]

Hi Mike,

 

I've been reading this thread with interest and have been enjoying seeing what you have been doing with the printed coach sides.

 

I thought I'd share my own effort at a GNR six wheel full brake in N gauge. This has been printed in FXD by Shapeways and is in the process of being cleaned up - almost there but not quite.

 

GNR Six Wheel Full Brake.jpg

 

It is a rather cruel close up (it's only c. 66mm long!) and shows that I've still got a couple of bits to sort out around a couple of the panels and re-scribe a couple of the doors. I've mainly used a chisel type attachment for the vertical panels and a sharpened jeweler's screwdriver for the horizontal ones. The roof was sanded using sanding sticks from Flory Models and Albion Alloys as they are quite cheap and foam backed so they follow contours pretty well.

 

Atso -

 

I really like what I'm seeing there. Is this a one-off, or are you doing anything else like this in N??

[MikeTrice]

A set of my Shapeways mouldings - GNR 6 Wheel Coach Fittings * 3 (https://www.shapeways.com/product/BUS5EW8N9/gnr-6-wheel-coach-fittings-3?optionId=60474530) sprayed matt black:

 

The lamps and ventilators have been carefully removed and glued to the roof. The lamps were done with superglue but for the vents I used 5 minute epoxy applied carefully into the holes from the underside of the roof. This allowed final alignment of the vents to be tweaked before the glue set solid:

 

For those desperate for me to cover the underframe, it is coming, promise!

[N15class]

These small details I think is where 3D printing comes into it's own. The large coach bodies will have a rough lined finish still after countless sandings and paintings.

 

these small fittings would even get me experimenting if they were the right railway and scale for my use.

[MikeTrice]

As promised, underframes.

 

I covered how to produce 6 wheeled chassis for GNR coaches in an earlier topic: http://www.rmweb.co.uk/community/index.php?/topic/112237-6-wheel-chassis-for-gnr-coaches-oo/. That topic went through the various options including suitability for narrow GNR prototypes and how they might perform on less-than-scale curves. I do not intend to repeat the various options here but instead will initially concentrate on my preferred option from that topic, using Bill Bedford sprung w-irons for the two outer axles and a simple free floating centre axle using internal bearings:

 

In the previous topic I tripped myself up by getting Bill's w-irons for 3'1" wheels mixed up with those specifically designed for 3'7" wheels which are required for these coaches. Bill very kindly identified which W-Irons I should be using:

 

BBWK003 RCH NPSC W-Irons

BBWF517 MR 6 wheel W-Irons

BBWF520 GWR 6 wheel W-Irons

BBWF031 LSWR 6 wheel W-Irons

 

Here is a photo of the MR I successfully used previously. The GWR version is similar with both having 3 W-Irons, fold down brake shoes and etched brake yokes:

 

Now if you model in P4 or EM then these are reasonable etches to go for, however if you are building your chassis for OO then the brake yokes are too wide and the brake shows do not fold down in the right place. One fret does 1 coach albeit with one brakeless w-iron left over.

 

On the other hand there is the RCH etch:

 

And the LSWR etch:

 

Interestingly these etches feature 6 w-irons and in the case of the LSWR fret separate etched brake shoes, so in my case the LSWR fret offers enough w-irons for 3 coaches given that I only use the w-irons for the outer two axles and positionable brake shoes.

 

Here is a MR w-iron as used previously with a Romford/Markits Mansell wheel. Note the clearance between the flange and the etching with the springs being at rest:

 

This is one of the LSWR w-irons to which I have fitted a Hornby wheelset. Note that the clearance from the flange to the w-iron is less:

 

If the wheelset is allowed to rise then there is the possibility of a short as the flanges touch the w-iron:

 

I will return to this issue a little later.

 

Meanwhile here is the RCH w-iron as supplied. Note that even at rest the flange of the wheels shorts on the etch and there is no possibility of the wheelset rising in its slot:

 

Even swapping a finer flanged wheel such as one with a P4 profile the issue with the RCH still exists. A search of the Internet identifies that this has also been noticed by the Scalefour Society: https://www.scalefour.org/forum/viewtopic.php?t=2205

 

 

 

 

 

 

 

 

 

 

Edited April 5, 2018 by MikeTrice

[MikeTrice]

Based on my experience in the previous post regarding the possibility of the wheelset shorting out when they "bottom" I decided to fret out the LSWR w-irons to provide more clearance and avoid contact:

 

A piercing saw made short work of the modification:

 

Could be neater but it serves its purpose:

 

In the earlier topic I used a simple jig to snip alternative w-iron wings. Needless to say both jigs used previously were sucked in by that black hole I mentioned so I had to make new ones. Herei s the new jig being used to cut the wings from 1mm N/S:

 

Hopefully you will get nearly identical wings:

 

To fit the new wings the old ones are snipped off and any remaining bits filed off. The new soldering jig has one of the cleaned up w-irons inserted:

 

The new wings can now be soldered to the w-irons:

 

Resulting w-irons after clean up of the excess solder and the bearing carriers ready to go:

 

The w-irons are folded up. Not an easy task and I have now invested in a folding tool which I have yet to try out. The rear face of the w-irons is masked off and they have been sprayed with primer:

 

For the floating axle in the centre of the coach I have previously used a modified version of a Dart/MJT internal wagon compensation unit so I was really pleased to notice that they had introduced a short version which should save messing around. I should add that I no longer have any involvement with Dart/MJT, they have done this themselves so many thanks:

 

They fold up like this:

 

 

 

 

 

 

 

 

[MikeTrice]

The spring wire supplied with the Bill Bedford w-irons has a distinct curve to it which I find almost impossible to straighten. Tarnishing is also often present:

 

That black hole having sucked up any guitar strings I might have bought in the past resulted in me having to order some replacements, in this Ernie Ball 10 thou (I also order 12 thou at the same time just in case). Much straighter (even though it comes rolled up in the packet, and no tarnishing:

 

New springs cut ready to replace the supplied ones:

 

Much happier with these:

 

Masking tape from w-irons removed, axle carriers and springs fitted and wheelset inserted:

 

No chance of shorting now:

 

Did I need to enlarge the cutouts in the w-irons? Having fitted Romford/Markits wheels with their finer flanges I might have got away by simply gluing a piece of paper to the w-iron bridge to avoid shorting.

 

With everything assembled I bend up the ends of the springs just to ensure they cannot slide out:

 

After trimming the excess bent ends of the springs the two outer axle units are epoxied in place between the solebars of the coach. Note that at the same time a piece of copperclad sleeper has been epoxied to one end to provide a solder point for the middle axle suspension wire:

 

The centre carrier has a piece of 0.6mm N/S soldered through the central holes which has then been sprayed black:

 

 

 

 

 

[Compound2632]

How do you get on with clipping the wire into Bill's three-fingered bearing unit? I'm about to do a dozen and from previous experience will be cross-eyed by the end.

[MikeTrice]

I don't have a problem. I use a fine pair of plier and bend back the three fingers slightly away from the half etched recess, place the wire in the slots and squeeze together. I don't bend them back too much, just enough to be able to insert the wires.

 

Thinking on this a bit more somehow I hold the carrier between my thumb and fourth finger leaving fingers two and three to hold one end of the wire in place while using the other hand to operate the pliers. Does that help?

Edited April 5, 2018 by MikeTrice

[Compound2632]

Yes thanks. Unfortunately I find I'm on finger twelve by the time it gets to slide the wire in...

[Dave John]

Ah , the same guitar strings I use for couplings and springs. I too leave them loose and bend the ends up . 

 

I'm following all this with interest, as I suspect most pre grouping modellers are. 

 

Though you got me addicted to the silhouette, and I haven't recovered from that yet ..... 

[MikeTrice]

A piece of sheet lead is cut and filed to fit in the recess of the internal compensation unit:

 

Then glued in place:

 

At this point I painted the solebars and headstocks Humbrol Acrylic 62 Leather having finally managed to purchase some following my earlier pots visit to the black hole. Ideally I would have painted these before adding the w-irons but managed to get away with it:

 

A paper template was knocked up to help me locate the centre axle which is then soldered to the piece of copperclad sleeper:

 

Next the swing of the centre axle was marked on the template to act as boundaries for drilling 0.6mm holes to take the strap that limits the central axle dipping:

 

A wire staple is added and raised/lowered until the centre axle can just drop below the outer axles and superglued from inside. This was my second attempt as the holes nearer the axle raised the risk of the wheelsets touching the wire:

 

So this is the point currently reached:

 

Point to note: for this centre carrier I soldered the N/S wire through the holes in the fold up sides of the MJT unit. In future I will remove those sides and solder the wire to the top of the saddle which will help reduce the amount of visible wire. Hopefully the axlebox/spring units will hide.

 

 

 

[JaymzHatstand]

This is looking incredibly good!

 

In certainly tempted to indulge, as I'll definitely need something to gang behind my Single and C1!

 

Looking forward to further updates

 

Cheers

 

J

[MikeTrice]

Adding the various springs and axleboxes makes it look more complete:

 

[MikeTrice]

Not a lot of progress.

 

A piece of lead weight has been epoxied to the inside floor. The vehicle now weighs in at 84gms which feels about right:

 

Holes have been drilled in the roof for the handrails. These have been countersunk underneath:

 

The new handrails are bent up, sprayed white and pushed through the holes and superglued underneath:

 

The tails have now been snipped off and filed flush.

 

To line or not to line? In for a penny so got out my lining tools which include a Kern pivotted blade ruling pen, some Humbrol enamel gloss yellow that has white added to it:

 

Now the long job of lining starting with the vertical lining on one side (really not enjoying this bit):

 

Need to let that go off before doing the next lines so it will be slow job.

[MikeTrice]

Photographic enlargements are cruel! Horizontals added:

 

Might have to go over a few again once these have dried.

 

[MikeTrice]

Second side lined. On Sunday I decided I should hone by Kern bow pen and played around with the paint thickness. Paint now flows much smoother, however the lines this side are slightly thicker resulting in a brighter line. Hopefully these will tone down when weathering is applied. Oh and it would have been MUCH easier to line if I had done it before adding the various chassis components and weight:

 

[MikeTrice]

Larry Goddard and Ian Rathbone, please look away now!

 

For the ends the lower beading was lined and put aside to dry (I said this was a long drawn out process). The step end was fiddly:

 

By comparison the non step end was much easier:

 

For the step end there are lots of bits that get in the way of the lining so I started as best I could leaving gaps the bow pen could not reach:

 

Turning the model round some more bits were added:

 

Turning round again the last bits were added. What a mess:

 

Inspired by Ian's book/video the lines were cleaned up using a fine brush dipped in clean white spirit and wiped almost dry then drawn along the edge of the beading:

 

By comparison the plain end was a lot easier:

 

And after cleanup:

 

Having looked at the enlargement I decided I could not live with that lining that missed the beading so have cleaned it off pending yet another lining session.

 

For cleanup I am using a Daler Rowney Gradual Round 1 brush:

 

And my old faithfull (now I have honed it) hinged Kern pen. The hinged blades allow me to open them up for cleaning without having to reset the lining width which is useful session to session:

 

 

 

 

 

 

[jwealleans]

Are you sure the ends were lined, Mike? On the assumption that you're going for the 1938 train, the photos I've looked at suggest not - at least for the leading BZ. The best I can find right now is the one on Steve Banks; site, which blows up quite large if you click on it. There's also the YFA film which only gives a very oblique view of the ends, but to my eye looks as though they aren't lined.

[MikeTrice]

I am not actually going for the 1938 train however I really cannot confirm one way or another that they were lined. NOOOOOOO!

[Bucoops]

I am not actually going for the 1938 train however I really cannot confirm one way or another that they were lined. NOOOOOOO!

 

Possibly not very helpful - but if they weren't lined they should have been because it does look good! I guess that as for the most part it wouldn't have been visible that may be why it may not have been lined.

 

I think that may be the vaguest paragraph ever?

[Compound2632]

Possibly not very helpful - but if they weren't lined they should have been because it does look good! I guess that as for the most part it wouldn't have been visible that may be why it may not have been lined.

 

I think that may be the vaguest paragraph ever?

 

If comparison with practice elsewhere is any indication it might be worth noting that the panel beading on the ends of Midland carriages was painted black, in the same way as for the sides, but the gold lining between the black and red was omitted. The LNWR went for plain brown or unvarnished lake ends without lining. So simplification seems likely. It looks to me as if the ends of the restored bogie and 6-wheel carriages are unlined but it's difficult to be certain from these photos.

 

EDIT: on the other hand, the end in the photo in your earlier post is lined...

Edited April 18, 2018 by Compound2632

[MikeTrice]

Well the lining has now been removed. A wash of white spirit and furious scrubbing with cotton buds seems to have got 99% of it off even after a couple of days drying. Phew!

[jwealleans]

The vehicle in the NRM photo (which is a D.303) is in correct ECJS livery. The 1938 train was made up (it is said) of old stock found lying round at Doncaster and was hurriedly restored to a version of ECJS livery. At that time the ends of non-vestibuled stock were not lined so it may be that it was overlooked, or that the expense of doing it was not justified for stock which only had a short anticipated service life, or maybe there just wasn't time.

 

I am doing the 1938 train, so these photos and film are pure gold.

[Compound2632]

The vehicle in the NRM photo (which is a D.303) is in correct ECJS livery. 

 

But (out of curiosity) is that the same as GNR livery in this respect?

[jwealleans]

In terms of lining, I believe it is, though the colours of lining and edging may have been slightly different.