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JCL

Using Inkscape and the Silhouette to create coach bogies

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Hi there, I'm hoping that by following on from Mike Trice's Inkscape tutorial in this forum I'm placing this tutorial in the right place. If not, please let me know where you'd like it.

Overview

This tutorial is a follow on from Mike Trice’s beginner’s guide to using Inkscape for creating cutting patterns. In the making of this tutorial I have shamelessly ripped off a number of ideas that have been detailed in the Silhouette Cameo thread, and my Wainfleet thread in my signature. I will be showing you how to create the Fox bogie in 4mm scale. I'm not some super modeller (I've been back in the fold for just over a year), but I hope that I can show how to use the Silhouette cutter to create what I thought would be impossible only a couple of months ago.

Of course there is the debate that we shouldn't be using the cutters to create things like this and we should be using castings, etc, but sometimes it's easier and more satisfying to do it yourself.

I'll be using the following:

  • .020" styrene
  • .010" styrene
  • top hat brass bearings

The plan is to:

  • Scan the bogie diagram into an image manipulation program such as Photoshop, Photoshop Elements, Gimp, Paintshop Pro, etc. I'm using Photoshop.
  • Manipulate it so that it's easy to see and straight
  • Open the result in Inkscape
  • Resize it and trace each of the lines
  • Separate out the layers
  • Import into Silhouette Studio to cut
  • Assemble the layers.

Scanning and Formatting your Diagram

post-14192-0-89371900-1390451599.png

We'll be tracing a printed plan to create the bogies. You can either download or scan in your plan. I’ve scanned mine in from “Historic Carriage Drawings, Vol. 1: LNER and Constituents” by Nicholas Campling. How you scan yours in will depend on your scanner, but hopefully you will end up with an image that you can manipulate. I tend to scan mine at the highest resolution possible and with as much contrast as possible.

Once you have your image in your drawing program:

  • Make sure that the horizontals are horizontal. In Photoshop you can use the ruler tool to trace a horizontal line on your plan, the longer line the better, and then use Image-> Image Rotation ->Arbitrary to line things up. Using the ruler tool first ensures that the angle needed to correct the image will already be in the box, so all you need to do is press OK.
  • If the background is greyish, and the actual drawing doesn’t jump out at you, play with the brightness and contrast until you get a good separation of line and background. If you know how to use them, then you can play around with levels to do the same sort of thing.
  • Crop the image so that just the bit you need is left. No point having a large image taking up your computer’s memory.
  • Save the result. If you save as a jpg, make sure that it is the highest quality. Better still, save your file in the png, bmp or tiff format

Inkscape

post-14192-0-84585500-1390451912_thumb.jpg

First of all we will need to import the image and make sure it’s the right size. I'll give you two different ways of doing this.

Resizing - Visually

Open your copy of Inkscape and use File -> Open to open the image file you just created. As you can see above, this image shows that the wheel centres are 10’ 6” apart. I'm probably teaching you to suck eggs, but 10’6”, or 10 ½ * 4 = 42, so the centres are 42mm apart in 4mm scale. I'm a visual person, so my preferred way of resizing is to:

  • Create a rectangle that is 42mm wide
  • Move the left hand edge of the rectangle over the left hand wheel centre (see image above)
  • Click on the bogie drawing so you get the resize handles
  • Choose the top right one, press the Ctrl key and move the handle in
  • You will notice that as the image gets smaller, the left hand wheel centre will no longer line up with the left side of the rectangle. Move the image over until it does
  • Repeat steps 3-5 until the sides of your rectangle touches the two wheel centres.

post-14192-0-29820400-1390452334.jpg

Resizing - Mathematically

Alternatively you can be more mathematical about resizing. When you have the bogie image selected ready to resize, you will see the following at the top of the screen:

post-14192-0-23447100-1390452482_thumb.jpg

All you need to do (!) is work out the percentage difference between the distance between the wheel centres in the original scanned image and what they should be.

  • On your original scanned image in Inkscape, draw a line or rectangle so that this time it touches both wheel centres. Click on the rectangle if it isn't selected. The image above will show the size in pixels, change the unit to mm.
  • You now know the starting distance in mm on your drawing, and you know it should be 42mm. My starting distance was 280.271mm. Using the formula (wanted size/starting size)*100 = % change, my numbers gave me
    42 / 279.856 * 100 = 14.98%. I need to reduce my image to 14.98% of its original size (it was a big scan!).
  • Select the image
  • At the top of the screen, make sure that the padlock is closed (click on it if it isn't).
  • Choose % from the unit select box
  • Type 14.98 in the width or height and press Enter

The image should now be the right size. You can check this by drawing another rectangle so that its vertical sides are touching the wheel centres and checking its width. When you are happy, delete the rectangles. If you mess it up, then just close the drawing down and reopen it.

A Quick Gotcha - Units

A quick note about that unit select box. I've noticed that it often resets itself to px, even if you use the program's preferences form to default to something else. Don't trust that the right units are being shown when you are resizing objects!

Next: Setting up guides

Edited by JCL
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Hi JCL,

 

and welcome to the group. I have been following your threads elsewhere and am impressed with the quality of the Silhouette output. As the topic falls loosely into the 3D and cutting headings I am happy to see it here and am looking forward to learning more and picking up on your modelling.

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Hi JCL,

 

and welcome to the group. I have been following your threads elsewhere and am impressed with the quality of the Silhouette output. As the topic falls loosely into the 3D and cutting headings I am happy to see it here and am looking forward to learning more and picking up on your modelling.

I'm in complete agreement, but also I'm profoundly appreciative of Jason's efforts (and Mike's and uax6's efforts) to show us the way to do things. Thank you, gentlemen !

 

Dennis

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Hi JCL,

 

and welcome to the group. I have been following your threads elsewhere and am impressed with the quality of the Silhouette output. As the topic falls loosely into the 3D and cutting headings I am happy to see it here and am looking forward to learning more and picking up on your modelling.

Hi there, I thought hard about where to put this as it's on the "outer edge" of your group. Thanks for letting me hang out. :)

 

Cheers too Dennis.

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Inkscape Guides

 

For me, guides are a very important part of putting together an accurate drawing. Guides are lines on top of your drawing, that are not a part of the drawing. They won't be printed or cut, and they cannot normally be exported to other software. When you create, edit or move objects, you can "snap" those objects to guides to make sure that they are the right size and shape and are created in precisely the right position.

 

Creating Guides

 

post-14192-0-16660800-1390508640.jpg

 

You can create a vertical guide by clicking on the left hand ruler and dragging the mouse over to the right until your cursor is where you want the guide to sit, then let go. Similarly you can create a horizontal guide by clicking on the top ruler and dragging down. If your guide is in the wrong place, you can hover over it until it goes red, then click on it and drag it to the right place. A guide is always one pixel wide, no matter how far you zoom in so it is noticeable but not intrusive.

 

In the illustration above you can see four guides; two horizontal ones and two vertical ones. The highlighted red guide is currently selected and about to be dragged. If you want to precisely position a guide, double-click on it and use the form that’s displayed.

 

Snapping to Guides

 

post-14192-0-70500000-1390508558.jpg post-14192-0-39506500-1390507973.jpg

 

I alluded to something called “snapping” earlier. Imagine a guide is magnetic, and if the cursor gets to close to it, the cursor jumps to it. Now imagine that you are creating a rectangle. If you put the cursor within 10 pixels of the guide, the cursor will jump to the guide. Now click and drag your cursor towards the next guide. Again, as the cursor gets within 10 pixels, it will automatically jump to the line. In this way, you will create an object that has a width that will be the same as the distance between the two guides. You did this without having to zoom in an carefully position your cursor. Not only is this more accurate, it also helps you to work faster.

 

Deleting Guides

 

You can delete guides in one of two ways; one-by-one, or all at once.

 

post-14192-0-53360800-1390508462.jpg

 

  • To delete a single guide, make sure that the arrow tool is selected, double click on it, and click on the delete button.
  • To delete all of the guides in one go, from the menus choose Extensions ->Render -> Guides creator. Then make sure that the drop down lists show Custom.., None, None, and Delete existing guides is ticked before pressing “Apply” and then “Close”.

Creating Guides for the Bogie

 

Back to the bogies. The Fox bogie is symmetrical about the centre-line, and some parts of it are freehand curves. This means that my plan of attack is to create one half of the design, copy it, flip it, and then join the two halves together to ensure that the two halves will be symmetrical. I will also be copying and flipping parts within the half bogie. This means that I need to provide guides around the whole bogie, and around one of the axlebox assemblies. There's nothing clever going on here as I've just created the guides by clicking and dragging from the appropriate ruler. Sometimes to be more accurate I've zoomed in to make sure that the guide is in the middle of the line thickness. This will be important later.

 

You will also notice that I have added guides at the point where a straight line becomes curved, and at the half way point between the wheel centres.

 

post-14192-0-04786900-1390509302_thumb.jpg post-14192-0-75979600-1390509300_thumb.jpg

 

Next: Setting up the workplace and drawing out the axlebox.

Edited by JCL
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Setting up the Workplace

 

Tool Option Palettes

I've got a bit of time, so I'll make a start on the half bogie. First of all I'll set up my workspace to get all my tool options together. I'll do this using the following menu options:

  • Object -> Align and Distribute
  • Object -> Fill and Stroke
  • Layer -> Layers...

post-14192-0-09077100-1390528499.jpg

 

Each of these menu commands will open a small palette of options that is docked to the right of the canvas that you'll be drawing on. Unfortunately the dock area can get cluttered easily, so on each of the docked palette is an arrow pointing right. Clicking this collapses the palette ready to reopen.

 

Layers

Next, I do what I should have done already, and set up two layers. One will contain the image, the other one will contain the cut lines. To do this:

  1. click on the + button on the layers palette, then choose the name "Image".
  2. click on the + button on the layers palette, then choose the name "Cut Lines".
  3. select the diagram, Edit -> Cut
  4. select the Image layer in the layers palette and Edit -> Paste in Place. The diagram will now be on the image layer.
  5. click the padlock next to the name. This will lock the position of the diagram and stop you from accidentally dragging it or otherwise editing it when you are doing other things.
  6. now click on the "Cut Lines" palette so that you can start adding the, erm, cut lines.

 

Axlebox

 

I could start anywhere, but I'll start with the axlebox. Because I'm only doing half a bogie, I only need to draw it once.

 

You will notice that I'll be using various tricks to nudge and cajole the various objects that I'm creating into the right shape and the right location. Some of these is because there is no other way to do it, and in other cases, it's because there is an obvious way to do it but I don't know what it is (answers on a postcard) ;) .

 

Axle Hole

First I'll create the axle hole. Although the circle denoting the axle hole isn't shown on the diagram we are using, it will be essential as it is where the bearing will be placed.

 

post-14192-0-67364300-1390529583.jpg

  1. Choose the circle tool and draw one 2mm in diameter.
  2. Click on the arrow tool.
  3. Click on the circle
  4. In the measurement fields at the top of the screen, make sure mm is selected, then make sure that you did indeed make a circle 2mm in diameter.
  5. You can either place the circle by eye, or, you can do the following:
    1. Draw vertical and horizontal lines that intersect.
    2. Place the circle over the lines.
    3. Select the circle and the vertical line
    4. Click on the "Centre on the vertical axis" button (the top button above)
    5. Select the circle and the horizontal line
    6. Click on the "Centre on the horizontal axis" button (the bottom button above)
    7. As you can see below, the two lines now show the centre of the circle. Select everything and move the circle over to the centre of the wheel.
    8. Delete the two black lines as you don't need them anymore.

post-14192-0-86030800-1390529836_thumb.jpg

 

Axlebox

This part of the bogie has an unusual shape that will be best created using the line tool (two buttons up from the A). Do the following:

  1. Choose the tool
  2. Click on a corner that you've already drawn two intersecting guides for.
  3. Keep clicking on corners until you have something like the shape below:

post-14192-0-83431600-1390530481_thumb.jpg

 

It might be that you will want to refine this shape, but it will do for this tutorial. We do need to refine the top left and right hand corners as they need be curves as you can see from the diagram.

  1. To enter Edit Point mode, either double click on the shape, or select it and choose the second button down on the left hand toolbox.
  2. Click on the diamond at the bottom of the part of the line you want to curve (see below).
  3. Click on this button to smooth the line post-14192-0-96441300-1390530828.jpg
  4. You will see two handles. Click and drag the bottom one so it is in line with the vertical guide (it should snap to the guide).
  5. Drag the top handle up until you get the shape you want. See the two images below.

post-14192-0-86711200-1390530970_thumb.jpg post-14192-0-47296600-1390530969_thumb.jpg

 

Do the same on the other side, and you should end up with the following shape:

 

post-14192-0-48547600-1390531095_thumb.jpg

 

Now all you have to do is draw some rectangles until you get the following axlebox

 

post-14192-0-20425900-1390531193_thumb.jpg

 

Now, all I need to do is make all the lines the same width and colour. I will also select the whole axlebox assembly and press Ctrl-G or Object -> Group to keep everything together.

 

There are other bits an pieces in there, so feel free to add them if you wish, it's just a case of creating rectangles.

 

Next: the rest of the half bogie.

Edited by JCL

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Just one final thing for today.

 

I'm going into the nth degree of detail here, and it looks like a lot of work. Although I've some experience from elsewhere, I only really started using Inkscape a couple of months ago myself, and now I've got to the speed where I would be able to get to this point in setting things up and drawing out the axlebox in less time than it took to write the tutorial. So please don't be put off.

 

I'm happy to answer any questions, or to provide extra pointers if anyone is having a go at this. And if I'm not around, I'm sure Mike or the others would be able to help.

 

cheers

 

Jason

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I am following along with this and started drawing a bogie of my own, still slow learning, so please keep it going. A bit worrying today to have to look through 15 pages of new posts to find it.

Thanks a lot

Keith

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I am following along with this and started drawing a bogie of my own, still slow learning, so please keep it going. A bit worrying today to have to look through 15 pages of new posts to find it.

Thanks a lot

Keith

Hi Keith,

Try following the topic (button at top right) and then from the choices on the left select 'topics I'm following'. Took me ages to find this method!

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Cheers Tren. Sorry about the delay, I put together the next installment last night. Today we are covering springs and rivets.

 

Springs

 

I had to think about this. Previously I just stole Mike Trice's springs (shhh), but obviously I needed to work out how to create the springs myself.

 

Lets go back to where we left off. The image below shows that the springs are a series of shapes that are joined together in layers. Although the springs that we are going to use will be made by creating multiple shapes, we will be joining them together into one block for cutting.

 

post-14192-0-22162100-1390839417.jpg

 

The first thing I did was to use the "Draw Bezier Curves and Straight Lines" tool (two up from the A in the toolbox) to draw a bent rectangle type shape. I started at the top left the spring, clicked again in the middle, but slightly lower down so that the click is in the top of the spring, then up to the top right. Down a little bit to the bottom of that first leaf, then I made sure that the next middle click left me with a parallel line. Finally two more clicks to finish the shape. So although there is that bend in the middle, all of the lines will be parallel. Don't get hung up on it though, just put up some guides or do it by eye.

 

post-14192-0-85375100-1390839737_thumb.jpg

 

The springs are curved, so I then clicked on the edit node button on the left, and selected the two middle nodes before clicking on the "Make selected nodes symmetric" button at the top. These are both highlighted in the picture below:

 

post-14192-0-32464300-1390839903_thumb.jpg

 

After changing the width of the line around the spring leaf (it defaulted to a wide thickness when created) using Object -> Fill and Stroke and changing the line width to 0.1 pixels (px), I then:

  1. copied and pasted the first leaf.
  2. made sure that the second leaf was selected
  3. clicked on that Edit Nodes button again
  4. selected the node I created in the top middle of the spring
  5. deleted it using the "-" button (second in from the letft in the top)
  6. I made sure that the left hand side was in line with the left hand side of the drawn second leaf, then used the arrows around the object  to shrink it into place.

For the sake of this tutorial, I also filled in the leaf so you could see them better. You delete the top middle node to make sure that there aren't any gaps between the leaves as this can become problematic when we later merge them into one large shape.

 

post-14192-0-06640700-1390840402_thumb.jpg

 

So the rest of the spring is easier. Just take that second leaf, copy and paste it, then move it into position and resize it. Do the same all the way down. A bit more nudging around and you should have a series of springs. To make sure it's symmetrical you can also select all of the springs at the end, then using the Align palette, click on Align Centres. If it's not quite right, then just nudge them about again until you're happy. This should give you something that looks like this.

 

post-14192-0-00933600-1390840661_thumb.jpg

 

Finally, you want a small circle on each end that the rod holding the weights will attach to.

 

Now save your work. I hope you do this regularly. I always save my work with different names at important points by adding a number onto the end of the file name. This means that if I make a huge mistake, I can always go back to the previous snapshot.

 

Next, you can see in the image below, you select all of the leaves you want to join together, and click on Path -> Union

 

post-14192-0-23129300-1390840862_thumb.jpg

 

Having removed the fill, I have the following spring like shape.

 

post-14192-0-63923700-1390841561_thumb.jpg

 

Rivet Holes

 

So now, we are counting rivets! In the image above, you can see there are four rivets on each side, On the left hand side:

  1. Draw your first rivet over the first "dot" (mine is .5mm diameter).
  2. Copy and paste that rivet over the last dot.
  3. Paste two more between the dots.
  4. Click on align left
  5. Click on Distribute Centres Equidistantly to line all the rivets up in a row.
  6. Select them all
  7. Group them
  8. Copy and paste them
  9. Move the duplicates to the other side.
  10. Select both columns of rivets and choose align top

Now, use those tools to create the rivets in the centre of the bogie to achieve the following:

 

post-14192-0-96218000-1390842470_thumb.jpg

 

Now take a step back and have a good look at what you've just drawn as we are about to duplicate and flip this half bogie to create a whole one. There are items I've not included (such as brake shoes), and there are items that you might draw differently, but hopefully we have something similar!

 

Next: Duplicating, Flipping and Merging the Two Halves

Edited by JCL

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Duplicating and Flipping

 

We're almost there. Now we have half of a complete bogie side, we need to duplicate it, flip it, and join the new half to the original half, so creating a whole side.

 

To do this:

  1. Select all of the lines you've drawn and group them together (Ctrl-G)
  2. Edit -> Copy then Edit -> Paste
  3. Make sure the new half is selected and press H or click on the button highlighted below

post-14192-0-09166000-1390842976_thumb.jpg

 

Now you have two halves, one slightly above or below the other. Select them both. Because they are a mirror image, if the new half is slightly below, click on the "Align Top Edges" button on the Align and Distribute Palette, if the new half is slightly above, click on the "Align Bottom Edges" button. I know that the two halves are perfectly aligned on the vertical axis, but if you look below, the new one is out of whack left to right.

 

post-14192-0-45462900-1390843206_thumb.jpg

 

All I do is just select that half, then use the arrow keys to move it left and right until I'm happy it lines up. Don't forget that pressing down the "Alt" key allows you to move left and right in smaller increments.

 

post-14192-0-11851400-1390843381_thumb.jpg

 

I'm happy with the bogie drawn in the image above, so now I'm ready to merge the two halves.

 

Merging The Two Halves

 

It is important that the two halves are lined up accurately for the computer, and not by hand. If they aren't, then you will have a small step between the two sides when we join them together. This is why I use the align tool as mentioned above. Also, by having that slight overlap in the middle, I've made it easier for Inkscape to work out what to join up.

  1. Ungroup everything (hopefully you only need to ungroup once using Ctrl-U)
  2. Deselect everything
  3. Select the first two halves to join together (I've coloured the two halves green below)
  4. Click on Path -> Union in the menu system

post-14192-0-32564800-1390843572_thumb.jpg

The two halves of the D shape are now one object.

 

Now I do the same with the outside edges. Again I've coloured them green so that you can see what I mean.

post-14192-0-17602300-1390843714_thumb.jpg

Press Ctrl-G to group everything together and save this with a special name. This is now your master bogie. In the next installment we will start converting it into layers to produce something that we can cut.

 

Next: Creating Sprues

Edited by JCL
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...and so much more accurate/obvious/better implemented than the merge function in Silhouette Studio which seems to work randomly!

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Just a quick note to let you know that I'll put the next installment up over the weekend. This will be the final part of the Inkscape work, and will show how the drawing is separated out into layers so the the layers can be cut out and put together. We will be using spruces and top hat bearings to make sure that everything lines up correctly.

 

Sorry for the delay.

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Merging Sides with Sprues

 

Adding Sprues

 

Now that we have the whole bogie drawn, we can start to separate out the layers like peeling an onion. Th one thing that we need to do is to make sure that we do not move any of the items on each layer, otherwise they won't line up when we come to build the plastic parts. Also if you decide to redraw something while you are creating your layers, it's often easier to do it o the master and then to recreate the split layers after that than trying to change a layer or groups of layers.

 

The first thing you need to do is to decide how many layers you are going to create. On this bogie, I am going to create three layers for the bogie sides, and another four layers that will be the axle boxes. To keep everything square, I will create both sides of the bogie at the same time and add "sprues" between the two sides.

 

First of all, I create two copies of the side, as I'm going to leave the original alone. I align them so that their tops are at the same height, and I draw two thin rectangles between them. Finally, I add an off-centre semi-circle to one of the sprues, and put the other at an so that I'll be able to make sure that the layers are the right way around.

 

Next, I add a couple of sprues that attach each of the two sets of springs. You'll notice again, the sprues are anything but symmetrical, and the sprues on each set of spring are different to make sure that we don't mix the two sets up. Later we will also add sprues to the axle box top layer.

 

The only reason why the bogies are vertical is that I find it easier to work that way.

 

post-14192-0-72978600-1391388805_thumb.jpg

 

Merging Sprues

 

So now we need to merge the sprues with the parts that we'll be splitting out. To do this:

 

post-14192-0-93651600-1391390279_thumb.jpg

  1. Make sure that the parts are ungrouped
  2. Select the two outside parts of the frames, the two sprues and the circle (selected parts are shown in green in the image above).
  3. Choose Path -> Union from the menu options

This will then give you the image below. As you can see, the two sides are now joined together by the two sprues.

 

post-14192-0-42359000-1391390429_thumb.jpg

 

When you have merged the springs together as well, you will get the following:

 

post-14192-0-71318400-1391390588_thumb.jpg

 

There will be some more merging to do later, but that'll do me for now. Select the whole thing and group them together (Object -> Group or Ctrl+G)

 

Next: Splitting into Layers

Edited by JCL

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Creating the Layers

 

Now we have the sides the way we want them (possibly!), all we have to do is separate them out into layers. The sides will be created from three layers of .010" styrene, and the springs and axleboxes will be created from five layers of .010" styrene. There will also be the axlebox covers.

 

Bogie Sides

 

The first layer (nearest to the wheels) won't have any details, the second layer will, and the third layer won't. The idea will be to use the holes in the second layer to locate where we will punch rivets into the third layer.

  1. Copy the original pair of sides
  2. Ungroup the details on the copy as we will be deleting quite a lot.
  3. Delete the springs and axleboxes, but not the circular holes. We need to keep them so that we can insert the bearings through them.
  4. Group everything together and make a copy.
  5. Ungroup the new copy, then delete all of the rivets and regroup
  6. Make a copy of the plain side.
  7. Regroup each set of sides. You will now have three grouped pairs of sides, one of which will have rivet details

post-14192-0-64333300-1391391819_thumb.jpg

 

Springs

 

We have the original pair of sides, so lets use this to create three copies. First of all, we don't need the actual sides themselves, just the springs and axleboxes, so I create a copy of the original (which I never touch), and then delete everything I don't need:

post-14192-0-20186900-1391392163_thumb.jpg

Now I make another three copies and remove the parts I don't need from each layer. For the first layer I will end up with the following image.

post-14192-0-28314600-1391392478_thumb.jpg

I will need to select the two "brackets" and springs and choose Path -> Union to join them all together. If I left a bit of overlap, then I will get the image below:

post-14192-0-66261800-1391392595_thumb.jpg

Now do the same with the next pair of sides. This time, you need to delete the bracket, but keep the axlebox. Then do the same with the next layer until you get the image below. In the image you can see that I've made each layer a different colour, and then shown how they all fit together in the complete bogie sides on the left. As you can see, the axlebox covers have been joined together with a final sprue that I drew from a rectangle and then merged using Path -> Union.

post-14192-0-38319700-1391393474_thumb.jpg

 

I said that there would be five layers in the final product. The axleboxes and spring assemblies will consist of one red layer, two blue layers, one olive layer, and the black axlebox covers, so I just make a second copy of the blue layer, and jobs a goodun.

 

Just to reiterate, I haven't moved any of the components while deleting the bits that I don't need on each layer. If you do manage to delete the wrong part, or nudge something out of position, then it is far easier to delete that layer and make another copy than to try to make it right. This is why I never use my original drawing, and always work on copies.

 

Anyway at the end of all of this, you should have this layout:

post-14192-0-57472100-1391394124_thumb.jpg

I will then make a few more copies than I need of each layer of the axlebox assemblies, just in case I have problems with getting them off the mat, etc. Each axlebox layer will be its own group so that I can move them around to make sure I don't use more styrene than I need to.

 

Finally, here's a larger image of how the layers will fit together - sorry about the colour scheme!

post-14192-0-27505800-1391394766_thumb.jpg

 

Next: Keeping the Sides Apart

Edited by JCL

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If you are going to use the sides cosmetically and glue them to the sides of a folded brass bogie, then your Inkscape work is done. If however, you are like me and are producing the whole unit from styrene, then you need to create the part that will hold the bogie sides together, and at the same time keep them apart.

 

First of all:

  1. draw some guides, one for each end, one on each side of where the wheel bisects the frame. Note that, if your wheels are a larger diameter than the ones drawn, you need to show where your actual wheels would bisect the frame, not the drawn ones.
  2. draw a rectangle that is the same length at the frame, and the correct width for your axle.
  3. draw rectangles that will become holes for the wheels to "poke through".
  4. Add a circle to the middle of the shape. This will be the pivot point for the bolt or whatever method you use for fixing the bogie to the carriage floor.Group the top plate and make a copy of it. Move the copy to one side, we will need it in a minute.

post-14192-0-68241300-1391453428_thumb.jpg

Select the main rectangle and one of the smaller rectangles. Choose Path -> Difference to cut four wheel holes. When you have done this, you will have the following shape:

post-14192-0-11907300-1391453432_thumb.jpg

Now go to the copy, this layer will be slightly wider than the first one because it will include the top flange.

  1. My plasticard is in inches, so I change the units at the top of the screen to inches
  2. This top layer will need to be the thickness of the two sides (6 x .010") plus the thickness of the flange (I'm going to use an extra .020" on each side) to give .10".
  3. I select the main rectangle, press the shift key, and drag the middle anchor upwards to increase the width by my calculated amount

Pressing the shift key means that the width will be increased both above and below the centre line. This removes the need to do a realignment afterwards.

post-14192-0-45933600-1391454272_thumb.jpg

After you have made a copy of the first layer, you will have the three you need and all of the sides.

 

You should now have all of the parts needed to cut your bogie. Remember that it might be an idea to create some copies of some of the more fragile pieces.

post-14192-0-74294000-1391454522_thumb.jpg

 

Next: Finally cutting the pieces out!

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Thanks Nimbus

Here's how the horizontal layers will work:

 

post-14192-0-82460800-1391470565_thumb.jpg

 

And here are the sides in order:

 

post-14192-0-00617700-1391472427.jpg

 

I hope that helps (though I'm not 100% sure that it does)

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It all looks very good. To me the axle boxes do not seem deep enough. On the bogie kits etc I have built they are as deep as they are tall. The ones in your plan are a lmm deep. In 4mm scale I would of thought 3mm more like it.

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Hi Peter, thanks for that

 

The way I did my test bogie was to use top hat bearings that Theakerr sent me. The sides and axleboxes were then pushed onto the bearings using a bit of weld and the seven layers I've given seemed to be about right. I think that the slight raised edges along each cut might make a difference too. I'm going to be putting together the sides tomorrow, so I'll be able to report back if another layer is needed. it might be that I have three layers of the blue cutout. I always cut more than I need, so I should be able to cover it. I did notice when I did my prototype that the "top plate" has to be wider than Mike Trice suggested to ensure that the sides are vertical, maybe this is a part of that.

 

cheers

 

Jason

 

Edited to make better sense.

Edited by JCL

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Something I did forget to do was to add some extra strength to the side frame layer that has all of the holes in it. Mike showed us this on the Wainfleet thread. (In this post http://www.rmweb.co.uk/community/index.php?/topic/63508-wainfleet-lincolnshire-roll-up-roll-up/?p=1305910)

 

To do this:

post-14192-0-10147000-1391547119.jpg

  1. ungroup this layer if you need to.
  2. add a rectangle either side of the frame (in pink below). Two rectangles will be inside the D shape, the others will be over the sprues.
  3. select the D shape, and the first rectangle that accompanies it
  4. select Path -> Difference. This is because we are going to take a chunk out of the D.
  5. do this again with the other D shape and the last rectangle

Next, select the outside line of the frames and the second rectangle, and select Path -> Union. Union, because we are adding to the outside of the frame. Do the same with the third rectangle.

post-14192-0-68444200-1391547119.jpg

Only make these additions to the layer that will contain the rivet holes. Later, after the frame layers are glued together, we will be cutting off these appendages.

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Cutting your Parts

 

That's almost all of the Inkscape work. Once you've checked everything you can move on to cutting the parts. For the Silhouette machines I still use Silhouette Studio at the moment.

 

The only thing you need to do in Inkscape now is save your file as a .dxf file using File -> Save As and then choosing Desktop Cutting Plotter (AutoCAD DXF R14) (*.dxf)

post-14192-0-85013300-1391624339.jpg

  1. Now in Silhouette open your file. You will have to change file type to *.dxf to be able to see it.
  2. Go to the page button and make sure that you have the right page size in there. This is important as you need to make sure that your drawing fits the sheet material that you are cutting into.
  3. If your drawing fits, great, you can move onto the cutting process. If not, read on!

Your drawing will be imported as something called a "compound path". You can drag this around to get the best fit. If no matter what you do you can't get the drawing to fit, you can either move things in Inkscape and resave, or you can break the group of objects up to move them independently.

 

To break up the imported drawing into its component parts, select it, and choose Object -> Release Compound Path. The whole drawing will be broken into its individual parts. Any groups that you had in Inkscape will be lost, so if you want to move, say, a W-iron, into a better position, then it's best to regroup it and then move it.

 

When you are done, you should have a layout like the one below:

post-14192-0-55429800-1391625088_thumb.jpg

 

Now you are ready to cut. Click on the button third from the top right to show the options in the image below. There's a bit of debate about the right settings to use when scoring and cutting. My machine doesn't seem to cut through with the same settings that other people use. The blade has numbers on it from 0-10. Each number equates to .1mm, so if you set the blade to 5, then it will stick out about 0.5mm. I always use a speed of 1 because I want the machine to cut as accurately as possible. I also always use double-cut.

 

I tend to score the card first before cutting it. I find that when I do this, the cut parts tend to be better defined with little or no wandering. Also, if you cut too deep with too much force, your card is more likely to ripple. So I use the following settings:

  1. cut with the blade set to 2 with a force (thickness) of 5 and a speed of 1,
  2. cut at 5, with a force of 20 and a speed of 1
  3. delete the rivet holes otherwise they could perforate your side if you keep going over them.
  4. cut at 10*, with a force of 33 and a speed of 1

* With regards to the blade setting, you need to be careful with this. Go too deep and you will mark the mat, so start light and go heavy until you find your own correct settings. Have a look at the Silhouette thread for more information about other people's settings. I find that with my machine, if I don't set a cut to 10, then I simply won't cut through.

post-14192-0-75753200-1391625190_thumb.jpg

 

You should end up with some cut parts. I always use a Stanley knife blade at a shallow angle to carefully remove them from the mat and put them to one side. In the image below, you can see:

  • the main horizontal pieces on the left
  • the frames on top right with the rivet holes
  • the side frames with the D waste ready to be popped out
  • some W-iron layers that have had their middle sections and axle holes popped out

post-14192-0-11793900-1391625983.jpg

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That's the Silhouette Cutter side of things finished. I'm not sure if I need to continue from here as the rest of the job is pushing rivets in a flat layer using holes in the rivet hole layer and gluing the various layers together in the order in the diagram above using the bearings for the correct registration.

 

I'm happy to continue though it you think it will be of help. Just let me know.

 

cheers

 

Jason

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Here's one more post for completeness. The first photo shows the various layers glue up with the axles centred using the top hat bearings. the centres were made a tight fit, so I used styrene weld to soften them slightly. You don't want to force them because the plastic will ride up and not stay flat.

 

post-14192-0-77385200-1392094366.jpg

 

This photo shows the sides glued to the top and the wheels added for show. The lip that I created by making the top horizontal layer wider is perfect for a stronger weld than just butting up against the middle. Of course you also have the advantage of creating the top flange. After this is a case of adding details, coupling and method of fixing to the coach underside. You ca see how I've removed the sprues, the middle one over the axlebox becoming the "wrap" keeping the springs together.

 

post-14192-0-64549400-1392143369_thumb.jpg
 

I hope you've all found this interesting. If anyone has any sort of diagram that gives the names of the various parts of the bogie, or carriage as a whole for that matter, I'd be very grateful if someone can post it up so hopefully I'll be able to bluff a bit more convincingly ;)

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I hope you've all found this interesting. If anyone has any sort of diagram that gives the names of the various parts of the bogie, or carriage as a whole for that matter, I'd be very grateful if someone can post it up so hopefully I'll be able to bluff a bit more convincingly ;)

 

There is some information at: http://www.railway-technical.com/suspen.shtml on a variety of bogie types and other railway technologies

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