QCAD - First Artwork

Discussion in 'CAD Corner' started by Lancastrian, 2 November 2019.

  1. Lancastrian

    Lancastrian Western Thunderer

    Had a couple of days getting used to the software, but with help from Adrian's tutorials and the fact that in functionality it isn't a million miles away from Templot, this is how far I have got with the artwork for some etched frames. Still a long way to go, and I've just ordered a digital copy of the works drawing to have more accurately read dimensions than I currently have.

    So far the artwork is for S7 and I think I'm doing everything right so far, but if anyone spots any glaring errors, please let me know.

    upload_2019-11-2_23-8-27.png

    Ian
     
    BrushType4 and adrian like this.
  2. Dikitriki

    Dikitriki Flying Squad

    Bloody Hell, not a Hoy 2-6-2? They never stayed on the rails long enough:)

    Richard
     
  3. mickoo

    mickoo Western Thunderer

    Are those frames jogged front and rear?

    If so you'll need to compensate with the front and rear axle positions, if you've laid the axle positions out as per 1:1 (scaled) on the drawing and then jog the frames afterward, the axles will move out of alignment, forward and backward.

    If the vertical red lines are not bend lines but half etch rebates for stays, then don't do that, it makes the frames very weak at those points, just cutting them from the etch sheet may cause them to bend ever so slightly and leave a witness mark.

    Far better to have two blind half etch areas top and bottom to locate them, better yet, full etch tab slots holes right through and then cover with an overlay on the outside that has etched rivets on.
     
    Dog Star likes this.
  4. Scale7JB

    Scale7JB Western Thunderer

    Looking good Ian, have you chosen your material gauge yet?

    You'll need to do this before you can further the artwork, so you know what size to make 90° fold lines. These are generally the thickness of the material you are using.

    JB.
     
  5. Scale7JB

    Scale7JB Western Thunderer

    There is a very good guide to producing etch artwork in the PPD website.

    JB.
     
  6. Lancastrian

    Lancastrian Western Thunderer

    Hi Guys,

    Richard, yes, and a lot of the stories about them not staying on the track are misleading tbh.

    Mick, yes, they are half etch lines for the frames to be joggled. The frame length at the front would be 3/64ths (0.3mm scale) longer when straight and 7/128ths (0.032mm scale) longer at the rear. I was considering a similar frame cross stay locating tab system similar to what Dave Sharp utilises with his kits.

    John, 28thou ? Is that the usual material thickness ? Frames are 1 1/16th inch. I have the Hollywood Foundry guide, but will have a look at the PPD site as well. In theory, I shouldn't have many etches to bend but that may change as I progress.

    I still have some tabs to add for the driving wheel axle sections and then the frame cross stays for the slide-bars and motion.

    Ian
     
  7. Lancastrian

    Lancastrian Western Thunderer

    I'll put your name down for one then shall I ? :thumbs:

    Ian
     
  8. SimonT

    SimonT Western Thunderer

    Ian, take a look at the PPD website as the materials are cheapest if you use metric sizes. That choice will inform a lot of your design. The Dave Sharp tab system is well worth adopting. If you are bending something through only 30 degrees you don't need a full width half etch slot, that only adds weakness. A chat with PPD to explain what you want to do should result in a recommendation of what width to adopt for what thickenss material/amount of bend.

    I'm still no wiser about a Hoy!

    Simon
     
  9. Lancastrian

    Lancastrian Western Thunderer

    Thanks Simon,

    http://www.lyrs.org.uk/images/uploads/LYRS_0599_-_Hoy_2-6-2T_No_1441_at_Bury_Shed_web_version.jpg

    Ian
     
  10. Scale7JB

    Scale7JB Western Thunderer

    I did find a picture of this previously. A very curious looking prototype, but I do like it!! Interesting to read that the centre drivers were flangeless during their lives.

    You may struggle with the frames behind the lead and trailing pony/radial (?) trucks. Will there be enough side play for toy train curves without having a cutout in the frames, or at least narrowing them below prototype width?

    JB.
     
  11. Lancastrian

    Lancastrian Western Thunderer

    Hi,

    The frames narrow from 4'2" between to 3'10" between for the radial trucks. Not sure if this will suffice for S7. I can always reduce the width of the cross stays if necessary, something I'd have to do for Finescale anyway.

    Ian
     
  12. SimonT

    SimonT Western Thunderer

    What a hulk!
     
  13. Lancastrian

    Lancastrian Western Thunderer

    Well, this is as far as I have currently got:

    upload_2019-11-7_14-11-45.png

    There is a little more work I can do before I will get to the point of awaiting the digital scan from the NRM, due the first week of December.

    Ian
     
  14. Dog Star

    Dog Star Western Thunderer

    Please excuse my asking... the image on my screen appears to have cut-outs for the horn-blocks with the rearmost side (LHS of drawing) of the cut-out at an angle to the vertical, if this is correct are you going to produce horn-guides and axleboxes with a wedge for take-up of tolerances?
     
  15. Lancastrian

    Lancastrian Western Thunderer

    Hi,

    At the moment, I haven't got as far as considering my options for the horn-guides. There is the possibility of doing them as etches, but I think it would be nicer if they were cast items. The inclined part of the frame cut-out for the horn guides is the leading edge. Additionally, I still need to find a drawing of the strengthening stretcher which runs longitudinally with the frames, as I believe this also contained horn-guides and a horn-block.

    Ian
     
  16. Scale7JB

    Scale7JB Western Thunderer

    I did have another thought, it looks like (purple layer) that you are doing construction likes and fills on one layer?

    May trip you up at a later date..

    JB.
     
  17. Lancastrian

    Lancastrian Western Thunderer

    Hi JB,

    So I'll need to remove the construction lines (purple) or transfer them to the Defpoints layer ?

    Ian
     
  18. Scale7JB

    Scale7JB Western Thunderer

    The etchers will only need the 3 fill layers required:

    - No etch - Black
    - Rear half etch - Blue
    - Front half etch- Red

    So it's worth keeping the construction layers seperate as they 'could' cause issues later on.

    Incidentally, I haven't yet worked out how to transfer elements to a different layer.

    JB.
     
  19. Lancastrian

    Lancastrian Western Thunderer

    Ah, so the purple layer will need to be changed to black ?

    I've found that if you select the layer you wish a line to go to, highlight the layer so there is a rectangle around the colour selection, then double click on the line and it should then transfer to the colour on that line. I'll double check that when I'm back home.

    Ian
     
    BrushType4 likes this.
  20. Scale7JB

    Scale7JB Western Thunderer

    Oooh I'll give that a go..

    JB.