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MikeTrice

Using Inkscape to produce cutting files, a worked example

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Your form of PTSD is at least partly curable. It's worth persevering enough to get the very basics, so you can use it to help with building pointwork, even if not whole layouts.

 

Let's not try to run before we can walk!  I can barely walk at the moment, figuratively, in terms of Inkscape, and, alas, literally at the moment!

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Let's not try to run before we can walk!  I can barely walk at the moment, figuratively, in terms of Inkscape, and, alas, literally at the moment!

I wasn't suggesting you should. Just offering hope for the future! If you literally (presumably in the traditional sense) can't walk, you have a good excuse to sit at the computer and practice ;).

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Sorry, my brain stopped working, and I posted something in the wrong topic :banghead:

Edited by BG John
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I have jumped ahead slightly and cut some styrene (I will return to this later).

 

Here are the layers, as designed, assembled, sprayed grey, and glazed:

post-3717-0-63215700-1473173034_thumb.jpg

 

post-3717-0-80854400-1473173035_thumb.jpg

 

post-3717-0-40909000-1473173037_thumb.jpg

 

post-3717-0-88239800-1473173038_thumb.jpg

 

post-3717-0-65377000-1473173040_thumb.jpg

 

In spite of taking extra care I still managed not to get all the laminations aligned correctly.

 

Having seen how this goes together I am considering combining the droplight and bolection layers together and adding a second 10thou glazing spacer layer to compensate. That will reduce the visual thickness of the window cutouts. Also worth trying the lower beading at 0.3mm rather than 0.5mm although that is pushing the Silhouette cutter to its limits.

 

Oh yes, need to do something about the door vents as well.

 

What do you think?

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The first photo is 96mm high on my screen, and my 7mm scale drawing is about 45mm high, so for a pretty cruel enlargement it's impressive. I haven't been able to get beyond the first step yet, so it's good for me that you've done a test cut now, and can make any changes you think necessary. Or do you think in 7mm scale it might be best to do it as you've just done, using 10 or 15 thou?

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At this point I don't know. Let me have a play and see how 7mm dimensions might impact the laminations.

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A quick experiment against a 7mm version of the drawing suggests the following intial thicknesses:

 

Panelling: 10thou

Side proper: 15thou

Bolection: 20thou

Droplight: 15thou

Outer glazing spacer: 20thou

Inner glazing spacer: 20thou

Inner side: 20thou

 

post-3717-0-17621000-1473182086_thumb.jpg

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Question. I have identified some changes to the layers to (hopefully) improve the finished coach. I could describe the changes in detail, however it does not really add anything that has not been covered before. So the question is do you what me to go into detail the changes made, or shall I just assume they have been made and move on to actually doing some cutting?

Edited by MikeTrice

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That's a difficult question to answer without knowing what the changes are, but if you gave us the information we need to decide, you wouldn't need to ask the question ;). I'm happy to leave it up to you. It would be nice to see the end result before I start catching up, to encourage me.

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I think I mentioned it earlier. Combine droplight layer with the bolection layer and create a new glazing layer in 10thou plus produce 0.3mm thick waist panelling.

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I think I mentioned it earlier. Combine droplight layer with the bolection layer and create a new glazing layer in 10thou plus produce 0.3mm thick waist panelling.

 

I am stupid.  I don't understand.  If the droplights and bolections are formed from the same layer, there would be one glazing layer to sit behind it?

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No there are now two glazing layers, one 10 thou the other 15 thou.

attachicon.gifscreen 0.jpg

 Still don't understand, so, presume still being stupid.

 

If the door light glazing is set further back than the quarter light glazing, doesn't the drop light frame layer need to be set further back than the bolections?

 

If, in the alternative, the bolections and droplight frames are the same layer, why are not their respective glazing also a single layer?

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I thought that the bolections sit on top of the panelling layer for the LSWR (like the rectangular pieces at waist level on your model) - they do on the bogie coaches I have been making, so that I have to prepare a vey thin rectangle to go round each quarterlight.  I am in France and don't have my copy of Gordon Weddell's book with me, so that I can't chreck that this was the same for earlier coaches.

 

Mick

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I thought that the bolections sit on top of the panelling layer for the LSWR (like the rectangular pieces at waist level on your model) - they do on the bogie coaches I have been making, so that I have to prepare a vey thin rectangle to go round each quarterlight.  I am in France and don't have my copy of Gordon Weddell's book with me, so that I can't chreck that this was the same for earlier coaches.

 

Mick

 

The picture below shows the feature we are talking about.  I suppose they are really the frames of the quarter lights, akin to those on the drop lights.  They are certainly not bolections like the type seen on some later coaches, e.g. GW Toplights, that stood proud of the coach side. 

post-25673-0-52078000-1473283092.jpg

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I accept that bolection is not the correct term for the window rebates on the prototype being modelled. Edwardian's photo (http://www.rmweb.co.uk/community/index.php?/topic/114528-using-inkscape-to-produce-cutting-files-a-worked-example/&do=findComment&comment=2420624) shows the detail much clearer.

 

 Sorry, Mike, I was evidently replying at the same time!.

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There is a section drawing on p.94 of Weddell, which shows the window moulding standing proud of the panelling.

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Thanks Bill. I assume you are referring to LSWR Carrages Volume 1 which I don't have. Anyone able to PM me a scan?

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 Still don't understand, so, presume still being stupid.

 

If the door light glazing is set further back than the quarter light glazing, doesn't the drop light frame layer need to be set further back than the bolections?

 

If, in the alternative, the bolections and droplight frames are the same layer, why are not their respective glazing also a single layer?

I think I can see where you are coming from. On the prototype it is highly likely that the droplight glazing is set further back than the quarterlight's glazing. It would be possible to build the body in such a way that the glazing could be accomodated by cutting individual pieces. Jenkinson's method on the other hand has a single piece of glazing that slides into a slot in the sides so it is necessary to cheat somewhat and design the sides with the glazing in a single layer. If you want to design and build your coach sides with the glazing correctly staggered, feel free to do so, however I am happy to accept the cheat as you end up with quite a strong side.

 

My original proposed layers for this model comprised the panelling layer, side proper, bolection layer (incorrectly named) and droplight layer all in 10th styrene. This resulted in a coach side measuring 1mm to the glazing in the quarterlights. I felt, rightly or wrongly, that that was probably excessive so thought to merge the droplight layer with the bolection layer into a single layer (effectively bringing the glazing nearer to the surface). This would give a thickness of 0.75mm to the glazing in the quarterlights. To compensate for this merging of layers I have had to increase the width of the slot for the glazing from 15thou to 25thou by adding a 10thou glazing spaer to the existing 15thou one. On the first sample made up I used 10thou glazing. For the revised design I can swap to 20thou glazing. The shape of the side including its turnunder remains unchanged.

 

I stressed at the time that this design process with the layers and resulting side curvature was important. Each prototype will probably have slightly different requirements, so someone following these notes to produce a different carriage type will need to be able to work out the layers for themselves rather than just follow what I have done. Likewise a change of scale will require adjustments. In 4mm I try and arrive at a scheme where I have an inner 20thou side which is vertical and two layers of 10thou full depth to form an outer side. In combination with other layers as required this results in a nice strong form that minimises warp. Hope that has helped and not just confused things.

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Thanks Bill. I assume you are referring to LSWR Carrages Volume 1 which I don't have. Anyone able to PM me a scan?

 

Yes, I can!

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There is a section drawing on p.94 of Weddell, which shows the window moulding standing proud of the panelling.

 

I have dug this out, preparatory to scanning.  I think we are looking at a later style, and, so, may assist with the sides generally, but probably not with the issue of the window surrounds. I will scan for Mike anyway.

 

It is possibly helpful to think of Mike's coach as a Metropolitan C&W design, rather than a LSW one.  Weddell notes its similarity to coaches supplied to other companies and surmises that it is a Metropolitan design.  To my eyes it is typical of mid-1860s-1870s coaches generally, and, for instance, is very similar to the GE coaches BG John and I have been considering. 

 

Common body features of the period appear to include raised beading on the waist and quarter lights in an inset frame, rather than behind protruding bolections.  The large radius rounded corners to the tops and square to the bottom are also typical.

 

Returning to the coaches in question, the example in question is from the 1871-74 period.  It is the same style as the first block set coaches of 1872-76. 

 

Later batches of these block sets built at Nine Elms from 1873  had revised quarter lights of the small radius curves to all four corners style, which is more familiar to us.  See text at p.67 and drawings at p.69.  It may be a moot point whether these new style quarter lights used the protruding bolections that we are also familiar with.  For this exercise, it does not matter, because the coaches concerned are the composite (p.62, and the Metropolitan built block sets, p.68).

 

Turning to the cross-section on p.94, this is a later generation of coach, under Adams's stewardship.  The details drawn are for circa 1884, and, to my eyes, seem quite typical of the panelling style generally adopted in the 1880s and 1890s by many companies.  The quarter lights are of the same small radius curves to all four corners style introduced by the SW drawing office in 1873.  It is clear that these have bolections.  This style was close to universal.  I know there were square window companies and that the GER adhered to the large radius top only curves throughout the ''80s and into the '90s, but many others, perhaps a majority, used this style.  It is, however, a later style.

 

The picture that I and Mike have posted (p.70), in detail and in larger view, is clearly of one of the block set coaches built by Metropolitan.  It is said to be built c.1873, but has the Metropolitan style quarter lights. It is a later photograph as the coach is in standard LSW two-tone livery and now sports gas lamps. 

 

It looks to me as if this coach does not have, and presumably never had, bolections protruding proud of the surrounding mouldings.  On the contrary, these appear, to me, to be recessed frames akin to those on droplights.  I could, however, be misinterpreting the photograph.   

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