New member Keith Bucklitch has asked:
"I model in gauge 1 (1/32nd) and 16mm:foot scales. Much as I would like to, I do not see myself as actually producing a gauge 3 model, as I already have enough projects in the pipeline to take me past receiving a telegram from the King. Currently, I am working on producing a Gresley LNER buffet coach (D 167) by 3D printing. The coach body is almost complete externally. The roof has yet to be satisfactorily modelled, especially with respect to the compound curve of the roof ends.
I was pointed to your site with reference to a set of drawings for this coach. I have downloaded these drawings, rescaled them and printed some of the parts to compare with my own model. I have found them to be very comparable in the dimensions of the parts.
If possible, I would like to correspond with the author of the gauge 3 drawings to see if we can swap ideas on modelling these vehicles."
You can contact Keith via PM at: https://g3forum.org.uk/index.php?action=profile;u=671
Martin.
Martin,
I am the guilty party and will drop a line to Keith.
Regards,
John.
Dear Mr. Candy.
I append an image of the coach as I have created it in Fusion 360 CAD software. The body of the coach is created with the walls and floor as a single entity making a U section box. (The ends are added subsequently after printiing.
My print bed measures 300mm square, so to fit the model on, I had to split it into three components, much as you have with your drawings. To align the components, I incorporated pockets and have inserted steel dowels into these. You can see the divisions of the body on the drawing together with the pockets for the dowels.
Instead of cut-outs for the windows, I have created glazing slots down from the top edge. However, I have found that these leave the actual window frames 1mm thick front and back, with consequent fragility. Some of the frames have not printed as well as they should, so I am considering removing the frames completly and printing separate 'plug-in' window frames to fit into the reveals. These will be printed on a resin printer whilst the body of the model is made on a filament printer. My walls are 3mm thick, but given the extra thickness of the walls for gauge 3 scales, it is possible that the window frames would actually print very well.
My model was based upon a 4mm scale drawing and consequently some dimensions are a little bit of guesswork. I rescaled and printed a complete side of your model and was gratified to find that the overall length of the two models was identical and there were only slight differences in the door and window positions.
Currently I am modelling the roof and am finding some difficulty in creating the compound curves of the roof ends, particularly in getting them to match up with the coach ends.
Finally, I am gathering information regarding the interior of the coach - layout, walls and partitions, kitchen fittings and furniture. Helpfully, my source drawing comes with a plan of the interior showing walls, seating etc as a starting point.
Regards.
Keith
For some reason, I could not attach the image file. Here is a second attempt.
Hello Keith,
I think I have made a reasonable job of the domed roof end (photos at end).
I haven't tried drawing one with a graphics package but it was fairly simple,if slow, to do with OpenSCAD (nearly 900 lines of code), plotting coordinates to building up the elliptical layers.
I shall, in view of time it takes to print one end, produce a mould and cast batches in resin.
The sides in G3 are 7mm thick above waistline, so the glazing is inset 5mm into back. The sides are printed face-up on the bed, so the glazing recesses are removeable supports.
The sliding ventilators are printed individually and are an interference fit into the window apertures (as are the toplights to the lavatory windows).
(http://g3forum.org.uk/index.php?action=dlattach;attach=5054;image)
As mentioned in my message to you, I am in process of printing a whole series of GCR and LNER carriages, with the Snapmaker pounding away 24 hours a day for months on end, so it will (at the rate of 200+ hours per carriage) be some time before I get to D167!
I used 4mm drawings (probably the same Nick Campling drawings you used) plus dimensions taken from the drawing in the Michael Harris book (which includes the internal layout plus a photo of the interior of one of the "Tourist Stock" D168 buffet cars, which were identical in internal layout to D167).
The partitioning and other internal bits for all my coaches will be a mixture of ply and plastic (laser cut/die cut and printed).
Regards.
John.
end1.jpg end2.jpg end3.jpg
Hi John. I don't seem to have received an earlier message from you, but no worry. I am still having difficulty in forming the curved ends in my normal CAD package, but a friend who uses a different system created a model for me which I was able to print, and am in the process of combining with the main body of the roof. (The model is currently on the Bromsgrove SME stand at the garden railway show at the Fosse this weekend.) Meanwhile, I am working on the interior of the coach, searching for illustrations of the interior fittings, especially in the kitchen and servery.
What layer height did you print your roof ends? I normally use 0.12mm which leaves only small visible lines on the print. A thin film of plastic putty smoothes them over ready for painting. The time it takes to make a print is not really important, as the machine is doing the work and one can be working on something else at the same time.
Keith
Hi Keith,
I sent my first message via the forum message system; it should be readable via the link at the top of the page (see screenshot). If it is not there, please let me know, since it means something is not right with the forum software and will need to be checked over.
I use 80 microns (0.08 mm) setting for prints I am going to use as parts but 160 microns if I am using parts to produce patterns for moulds (they are very much faster to print but need a little more sanding to smooth). The item in my photo of the roof dome is a pattern for a mould, hence 160. The Snapmaker will print at 50 microns but the massive extra time it takes is not worth it in terms of a finer "finish".
I will scan and send the interior picture of buffet car tomorrow.
Regards,
John.
mssgebox.jpg