S7 scratch building

[airnimal]

I am not happy about the dimensions of my build. The drawing i am working from is to 8mm to the foot not 7mm which would have been more helpful. Before I decide to scrap it I will do what I should have done at the beginning and get the drawing reduced to 7mm. I will be going past the photo copying shop later. I am getting more railway stuff scrapped than Dai Woodham.

[airnimal]

As I suspected the body dimensions were a little out. I had the drawing reduced to 7mm which enable me to compare my efforts directly without guesswork. The drop down doors were wrong and were removed but the main mistake was the gap at the top of the body. I had to remove 2mm from the top upright timbers and fill in the holes where i had put the tie rods. The plank side panels were also out but not by much. These were also removed and a start has been made on rebuilding using some of the old bits.

Edited September 24, 2017 by airnimal

[airnimal]

I hope I have got it right this time. It does fit the 7mm drawing. I will keep my fingers crossed as with past experiences I have been here before.

[Western Star]

Mike, the sheeting looks like a single layer of blue 20th plastikard...  if that is the case, how have you done the plank lines on each side without breaking through the plastic?

[airnimal]

Graham, you are correct the side sheets are a single layer of blue 20 thou plastkard. I scribe the plank lines with my usual tool, a Olfa knife on both sides with just one stroke each side. I then lightly sand the burr off and clean out the grove with a old toothbrush. I had to be very careful not to put to much pressure on at any time because the parts are very fragile.

I will not be at the workbench for a couple of days as a new member of the family arrived last night, I have a second grandson. The next generation railway modellers ?

[Andy Hayter]

No congratulations icon to tick, so I will just have to write it,

 

Congratulations.

[N15class]

Looks good. Just one thing it's not actually a vee join between the planks. The top of the lower plank has a chamfer, but the bottom of the upper plank has a square corner. This help keeps the joint dry as the water will tend to drop off onto the lower bevel and run away from the joint. Two chamfered edges would tend to drive the water between the planks not ideal at all. I sharpened an ofla blade to only have one bevel, used with a steel straight edge it leaves a lovely grove. You can only cut with straight edge on the straight side or it wanders all over the place.

[airnimal]

Thanks Andy for your kind message. The little fella hasn't got a soldering iron in his hands yet but he will have in time. My other grandson who is 10 could solder by the time he was 8.

Peter, you are of course right about the plank grove. I will get around some time to grinding one of the Olfa blades as you described.

Hopefully I now have the basis for the right dimensions for this cattle wagon. I still have a long way to go but I hope I am going in the right direction.

[Western Star]

Mike, this post is not meant as a criticism...  more as a thought about how this wagon may behave over time.

 

You have used 20thou blue plastic for the sheeting of the opening doors and your last photo shows that you have fixed the sheeting to the back of the door framing so you have circa(?) 60thou of overlap between the sheeting and the framing.  You have used the same plastic for the sheeting of the quarter panels and the photo suggests that the sheeting is fixed to the frame by an edge butt joint.  What concerns me here is that if the sheeting "moves" - temperature / humidity / effect of paint solvent / finger pressure - then the butt joint is going to be put under shear stress and break.

 

Or have I failed to understand your construction?

[airnimal]

Graham, yes you are correct the ends of the blue planks are butt joined against the 60 thou frame. But the planks are also glued to the diagonal frame which will help with the strength. I have not had any problems over time with the way I have made this wagon but I do hear what you say about temperature / humidity. With the open nature of the construction that I am using this was the way I thought at the time to be the best.I am making the build up as I go along and hindsight is a wonderful thing and It may have been better to make the planks sandwiched between the uprights in layers but .....

[airnimal]

Now the end timbers are on and sanded to shape the basic body is now complete. I have put a couple of spacing bars to keep the body from folding inwards. I have seen photos of open cattle wagons with this feature but I can't remember where. Irish narrow gauge perhaps?

All the iron work has yet to go on with bolts and hinges and the other bits and pieces.

[Western Star]

I have put a couple of spacing bars to keep the body from folding inwards.

Given the open nature of this wagon you might like to think about using perspex sheet, say 125 thou thick and 1" wide, as a brace between the doors.

 

In the limit, the perspex could run end to end as a false roof...  in which case make the strengthener from 80th styrene for material compatability.  No worries about solvent fumes here.

[Regularity]

That's all rather nice, Mike.

 

One question about the side sheeting, based on ignorance (on my part) of the prototype, but 20 thou in 7mm scale works out as somewhere between ¾" and ⅞" thick. I presume that because of the bracing, this would not have been required for structural strength (unlike an open wagon) but would it have been that thin?

[Compound2632]

That's all rather nice, Mike.

 

One question about the side sheeting, based on ignorance (on my part) of the prototype, but 20 thou in 7mm scale works out as somewhere between ¾" and ⅞" thick. I presume that because of the bracing, this would not have been required for structural strength (unlike an open wagon) but would it have been that thin?

 

I do like the prototypical approach to construction Mike takes here - my instinct would be to start with a flat piece of plasticard for the planking and add the framework, but I'm a 4mm scale modeller; the stand-alone framing would be trickier. Looking at the Earlestown drawings for cattle wagons in LNWR Wagons, Vol. 1 (WSP, 2001), the thickness of the sheeting isn't given on drawings earlier than an 1897 drawing of a large cattle wagon, where it is given as 1 1/4", which is 0.73 mm / 0.029" or near enough 30 thou. The construction details of this later wagon are essentially the same as Mike's semi-sprung-buffered unroofed wagon, so although I would guess it dates from at least 30 years earlier, I would be surprised if the thickness was any different. It's not very clear from the drawings but I think the side sheeting fits into a rebate on the inside face of each vertical pillar, just as the end sheeting fits into a rebate on the outside.

[airnimal]

Graham, I do not like the idea of a perspex roof or as a brace between the doors. I think you would see both of these and would distract from the open look that I am after.

As for the planks being to thin, I do not think you would notice to much. I don't think I am going to loose much sleep over this.

I am going to Wigan show tomorrow to see some trains. Management has given me a pass out as I have been a good grandad doing all the right things at the right time. Mega brownie points.

[Western Star]

I am going to Wigan show tomorrow to see some trains. Management has given me a pass out as I have been a good grandad doing all the right things at the right time. Mega brownie points.

Mark on the 14th?

[airnimal]

Yes I hope to be there. My eldest daughter lives in Swindon so I will probably go there on the Friday night and drive to Mark on the Saturday morning.

[airnimal]

After a hectic weekend I am now able to get back to the workbench and do a bit more.

[airnimal]

I am slowly building up the details on the end, but it is a slow job and I can't work very fast.

[Coal Tank]

Just superb Mike

John

[airnimal]

Coal Tank, thank you for your kind words. Do you model the North Western ?

I did a little more on the cattle wagon this morning to the interior detail.

I then returned to the loco coal wagon because I was not happy how the brake rack was. I thought it sat to far out from the wagon body.

I removed the handle and rack and made a new one. I think it looks so much better now.

[airnimal]

I think I have gotten all the ironwork on but not the bolt heads. I now have to decide if it is worth trying to put the chamfer on the edge of the timbers. In the past I have done this on brake vans and other vans using a little trick of putting a backing piece of brass in to the opening for the blade to rest against. I mark the start and the end of the chamfer with a pencil and then put a small notch in with the blade before dragging the blade along the edge. This is a risky business that can go wrong. Decisions decisions ?

[Western Star]

Why did the LNWR put dumb buffers at one end...  and sprung buffers at the other end?

 

Might I get to see this model in just over a week?

[Caley Jim]

I think I have gotten all the ironwork on but not the bolt heads. I now have to decide if it is worth trying to put the chamfer on the edge of the timbers. In the past I have done this on brake vans and other vans using a little trick of putting a backing piece of brass in to the opening for the blade to rest against. I mark the start and the end of the chamfer with a pencil and then put a small notch in with the blade before dragging the blade along the edge. This is a risky business that can go wrong. Decisions decisions ?

I think the chamfer on this type of vehicle is an important part of the character.  I reproduce it on my 2FS etched kits by having the top ½-etched layer set back slightly from the edge of the layer below, letting the paint form the chanfer.

 

 

Excuse the crappy lettering, this photo's coming out at about 4x life size!.  

 

Jim

[garethashenden]

Why did the LNWR put dumb buffers at one end...  and sprung buffers at the other end?

 

Might I get to see this model in just over a week?

Fairly common actually in mid-late 19th century. You get most of the benefit of sprung buffers but for half the cost.