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Post by greenbat on Dec 9, 2022 12:06:05 GMT
Doug, where do you get the idea you can simply bolt together 3D printed parts with no machining? I'd assume that the 2D drawings will only have the dimensions for machined features-so, for example, the wheels will have tread and axle details but not the full dimensions of the BFB centres. Almost like every other design that uses conventional castings. So you'd not be able to reverse engineer the 3D model. As ever, I'm hugely impressed at this project, thankyou for updating us  |
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Post by masahiraoka on Dec 9, 2022 20:00:01 GMT
Thanks Bob and Doug
Doug I agree that most model engineers gain more from the building than the operating of locos but there are undoubtedly some who because of the pressure of time or lack of skills could be interested in utilizing our parts and design. This would enable them to build a high quality loco within a reasonable time period and possibly stimulate them to once finished go on to build locos by more traditional means.
ciao Martyn
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cfmrc
Seasoned Member
Posts: 107
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Post by cfmrc on Dec 24, 2022 9:57:48 GMT
Will the 3DP for e.g. the valve gear be slightly oversized to allow ‘finishing’ to a sharp final size?
A very impressive project - would be a good follow on to my King Arthur.
Tim
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44767
Statesman
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Post by 44767 on Dec 24, 2022 10:42:14 GMT
I'm not quite sure what the problem with 2D drawings is. Until CNC came along, 3D engineering drawing was almost unheard of, except to illustrate an object; never to machine it. I was an engineering design draughtsman for many years, and worked in 2D and 3D. CNC was in it's infancy so everything we manufactured, was machined to 2D drawings, but 3D drawings were used to show assemblies. Everything in the engineering world, was manufactured from 2D drawings, before CNC. 3D drawings give you a picture of what something will look like when finished, or assembled, but for actual manufacturing (machining) 2D drawings are the most important. If you think about the machining of an item, you can look at a solid item, which IS 3D in life, but what you are seeing is actually a 2D face, and dimensions are all against 2D faces. Martyn is quite right to not publish full 3D drawings. Anyone with access to any CAD software that can read his drawings, can generate full working, fully dimensioned, working drawings. Definitely NOT a good idea to publish fully detailed 3D drawings. If Martyn's drawings have been proved by him manufacturing a couple of models to the drawings, the only need, technically, for 3D drawings is to give an idea of the final shape of things, and to check the dimensioning has no clashes. Bob. I see where you're coming from, Bob, but are you mixing up 3D solid models, as produced by the likes of SolidWorks software, with isometric drawings? Most parts these days are machined on the shop floor from 2D drawings which were created from solid 3D models. Any surfaces which are not orthogonal are machined as surfaces from the same models. Martyn will supply drawings which allow the machining of components to suit the model's design just like almost all model designs have done in the past. In this regard, he has already done the hard work in supplying a casting or, perhaps, a fabrication which only needs final machining. This is a far cry from most model designs where, given the final part drawing, it is up to the modeller to work out how to fabricate the part prior to machining. Mike |
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44767
Statesman
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Post by 44767 on Dec 24, 2022 11:11:51 GMT
I personally think the point is being missed, I am building a 2.5” model of sir Keith park, 2d drawings alone just give me the building blocks to build a 3d model from which I CNC all my own parts, this is how I have built speedy and how I do model engineering. I expect new engineers to the hobby would be interested in a similar approach. Using a kit of 3d printed parts for me is not engineering it’s building expensive mechano fine for people without or little engineering skills yet not very interesting for me. Making for me is more fun than using. I don’t see the IP issue being relived by giving away the 2d design and holding on to a cad model. Anyone with drawing skills can replicate the 3d design from 2d drawings. All seems a bit odd and lost on me. Lovely work though. I agree that some new model engineers will be interested in working out how to make a part from a 2D drawing only, especially if he has some interest in CNC work or the desire to learn CAD modelling. This is how it's been done for a very long time! Apart from the occasional casting, there has often been no help to build a model once the 2D drawings have been supplied. So you'd be in your element building this model from the 2D drawings alone, reverse engineering the castings and fabrications from them; I've got no problem with that. Martyn is going one step further, to help many, in supplying castings and kits for fabrications which will make the build much easier for anyone, especially first time builders. 3D printed parts are not any different to a casting; they still need machining. The advantage is that small runs can be made without the need for tooling (patterns) therefore often making them cheaper to produce. Perhaps the only issue for Martyn is that he intends to supply the drawings free when you purchase the castings and kits of materials- not sure where that would leave you. Mike |
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Post by 92220 on Dec 24, 2022 12:11:48 GMT
I'm not quite sure what the problem with 2D drawings is. Until CNC came along, 3D engineering drawing was almost unheard of, except to illustrate an object; never to machine it. I was an engineering design draughtsman for many years, and worked in 2D and 3D. CNC was in it's infancy so everything we manufactured, was machined to 2D drawings, but 3D drawings were used to show assemblies. Everything in the engineering world, was manufactured from 2D drawings, before CNC. 3D drawings give you a picture of what something will look like when finished, or assembled, but for actual manufacturing (machining) 2D drawings are the most important. If you think about the machining of an item, you can look at a solid item, which IS 3D in life, but what you are seeing is actually a 2D face, and dimensions are all against 2D faces. Martyn is quite right to not publish full 3D drawings. Anyone with access to any CAD software that can read his drawings, can generate full working, fully dimensioned, working drawings. Definitely NOT a good idea to publish fully detailed 3D drawings. If Martyn's drawings have been proved by him manufacturing a couple of models to the drawings, the only need, technically, for 3D drawings is to give an idea of the final shape of things, and to check the dimensioning has no clashes. Bob. I see where you're coming from, Bob, but are you mixing up 3D solid models, as produced by the likes of SolidWorks software, with isometric drawings? Most parts these days are machined on the shop floor from 2D drawings which were created from solid 3D models. Any surfaces which are not orthogonal are machined as surfaces from the same models. Martyn will supply drawings which allow the machining of components to suit the model's design just like almost all model designs have done in the past. In this regard, he has already done the hard work in supplying a casting or, perhaps, a fabrication which only needs final machining. This is a far cry from most model designs where, given the final part drawing, it is up to the modeller to work out how to fabricate the part prior to machining. Mike Hi Mike. No. I wasn't thinking of isometrics. I am well aware that 2D drawings can come from 3D solid works, when available. I used to use full Autocad solid modelling back in the 1990s, to produce drawings for the experimental gas powered air conditioning system, that the company was working on, and took 2D drawings from the 3D drawings when I was a contract design draughtsman. Yes you did read that right...a gas fired air conditioning system.....and it worked. Problem was we couildn't get it down to a sensible, marketable price. I probably didn't express myself to well (its an 'age' thing, I guess!!!) I was just trying to say exactly what you have pointed out, that a full set of 2D drawings, from which the parts are made, can be taken off by anyone who has the 3D drawings, so I was agreeing with Martyn, that they should not be available commercially so that drawings can be 'ripped off' and sold, by people other than Martyn and his partners. 2D drawings are what a part is made from unless made on CNC. If someone wants to use CNC to make the parts for Martyn's loco, then, rather than supply a full set of 3D drawings in file form, that can be pirated, he can supply the necessary CNC files for a price. The other problem with even supplying files for use with CNC is that if the details come off a 3D assembly drawing, anyone with those 3D assembly drawings can pull off manufacturing drawings for all the parts that Martyn will sell too. It's all about protecting Martyn's IT. I'm sorry, I just didn't express myself properly in my previous post, and for that, I must, as I said, put it down to an age thing!! Bob. |
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Post by Doug on Dec 29, 2022 21:51:07 GMT
Hi Bob FYI CNC programs are not transferable between machines, programs are made specifically for the size, shape, type and datum’s of the machine and more importantly the capabilities of each machine so this project is useless for someone wanting to do what I am attempting, a 2.5” version with CNC parts (programs are also not scaleable). Lots of lovely work and detail has gone into the CAD model and it’s a shame it won’t be available. However Ariel drawings have been available for many years so the chances of someone bothering to rip off the design from the CAD model is probably slim IMO.
In a small positive is that I am now continuing with my CAD model as I now know I won’t be able to buy this one. Having done some more small details recently it has reminded me how much fun it is so can’t complain really.
All the best Doug
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Post by terrier060 on Mar 8, 2023 23:12:43 GMT
Hi Martyn
Forgive me if this has already been discussed, but is there a restriction in the metal you can use in 3D printing. Can you print the equivalent of mild steel, gauge plate silver steel etc.?
Ed
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Post by 92220 on Mar 9, 2023 9:06:27 GMT
Hi Bob FYI CNC programs are not transferable between machines, programs are made specifically for the size, shape, type and datum’s of the machine and more importantly the capabilities of each machine so this project is useless for someone wanting to do what I am attempting, a 2.5” version with CNC parts (programs are also not scaleable). Lots of lovely work and detail has gone into the CAD model and it’s a shame it won’t be available. However Ariel drawings have been available for many years so the chances of someone bothering to rip off the design from the CAD model is probably slim IMO. In a small positive is that I am now continuing with my CAD model as I now know I won’t be able to buy this one. Having done some more small details recently it has reminded me how much fun it is so can’t complain really. All the best Doug Hi Doug. Sorry. I didn't put down exactly what I meant to say! Again!! I fully accept that CNC programs are machine specific. What I meant to say was that the 3D drawings should not be available as computer files, because any CAD program that can read the files and export them as a file suitable for use with CNC. As is probably quite obvious from my writing, I know almost nothing about CNC, but I did do a lot of 3D drawing when I was a draughtsman, using my own full Autocad. I understand, from what I have read on the internet, that "CNC typically uses STEP, DXF, or SVG files". The one file form cottoned on to is the .dxf. There are a lot of CAD programs out there, that can convert 2D and 3D drawings to .DXF files form. That seems to me that any drawing file in 3D that has been converted to .stl file form, can be used to machine something on a CNC machine that can read .DXF files. I may be wrong, but am quite prepared to accept that I have things completely wrong. It is just that that is how I saw it. Bob. |
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Post by Doug on Mar 11, 2023 18:01:48 GMT
Hi Bob FYI CNC programs are not transferable between machines, programs are made specifically for the size, shape, type and datum’s of the machine and more importantly the capabilities of each machine so this project is useless for someone wanting to do what I am attempting, a 2.5” version with CNC parts (programs are also not scaleable). Lots of lovely work and detail has gone into the CAD model and it’s a shame it won’t be available. However Ariel drawings have been available for many years so the chances of someone bothering to rip off the design from the CAD model is probably slim IMO. In a small positive is that I am now continuing with my CAD model as I now know I won’t be able to buy this one. Having done some more small details recently it has reminded me how much fun it is so can’t complain really. All the best Doug Hi Doug. Sorry. I didn't put down exactly what I meant to say! Again!! I fully accept that CNC programs are machine specific. What I meant to say was that the 3D drawings should not be available as computer files, because any CAD program that can read the files and export them as a file suitable for use with CNC. As is probably quite obvious from my writing, I know almost nothing about CNC, but I did do a lot of 3D drawing when I was a draughtsman, using my own full Autocad. I understand, from what I have read on the internet, that "CNC typically uses STEP, DXF, or SVG files". The one file form cottoned on to is the .dxf. There are a lot of CAD programs out there, that can convert 2D and 3D drawings to .DXF files form. That seems to me that any drawing file in 3D that has been converted to .stl file form, can be used to machine something on a CNC machine that can read .DXF files. I may be wrong, but am quite prepared to accept that I have things completely wrong. It is just that that is how I saw it. Bob. Hi Bob didn’t mean to come across as a pedant. I personally was very disappointed by the decision not to release the cad files on this project as I am building a 2.5” sir Keith park (once I get my speedy finished) the cad files are in my view no more valuable to the general community than the 2d drawings mostly due to the small market and demand thereof. the stl files and dxf files are not transferable to CNC those formats require lots of work with a CAM (computer aided machining) program to make an NC file that the CNC can use machining with a CNC is way more difficult than conventional machining as all sorts of other factors come into play like fixtures, tool paths, speeds and feeds and tool changes etc. none of this is easy and almost certainly not worth the effort for a company to steal the IP from the work Martyin and his team has done due to the very small market. This is of course my view only and it’s his decision to deal with his teams work as he sees fit. I only put this down for explanation only not to argue any point. All the very best Doug |
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Post by masahiraoka on Jun 16, 2023 6:28:54 GMT
Notes on the issuance of Rebuilt West Country CAD drawings There has been much debate on this blog about the pros and cons of what we are intending to do regarding the issuance of CAD drawings for our rebuilt West Country Pacific so I thought I’d set out exactly what we intend to do and why, and the implications for model engineers who may be interested in utilising the drawings. Firstly, can I say that a huge amount of excellent effort has been undertaken on the development of this design including 5-man years of Phil’s time on the 3D CAD model and production engineering and 1 man year of time on Nigel’s time on the 2D CAD drawings. We need to protect this intellectual property over time, not because there is any sense that we will make a commercial return on the investment but because we want to protect the integrity of the design, the quality of the resultant manufactured parts and the overall experience of the model engineer who chooses to build one of these locos. We know that this type of model engineering is not for everyone, i.e. the supply of complex high quality parts to be machined and assembled by the model engineer which should result in the creation of a high standard loco in, we’re guessing, one quarter of the time usually required to build a similar size and quality loco. We know that many model engineers get most of the enjoyment and satisfaction from the building rather than the running of locos, but we feel that there will be some who would like to join in the fun but don’t have all the skills necessary to build a complex high-quality loco. Time will tell whether we’re right or wrong in this belief. Basically, we intend to provide the whole set of 2D CAD drawings, on paper, free to those model engineers who purchase the manufactured parts from us. Before the commercial release of the manufactured parts, we have already made available, on this blog, eight of the major assembly drawings with the probability of a few more being added shortly, see table below. Note that the 2D CAD drawings already released on the blog will be updated from time to time as revisions are made, something that has been done recently. List of Released Drawings Sheet No. Date & Link to PostThe 2D CAD drawings are dimensioned to a level that will enable those engineers who buy the 3D printed / precision cast parts to machine them ready for assembly. The 2D drawings will not contain the degree of dimensioning that would enable engineers to make the components from scratch either by fabrication, casting or other method, i.e. there will not be sufficient dimensions to reverse engineer the 3D CAD model. We will not be releasing the 3D CAD model for the simple reason that it is that which embodies all our intellectual property. Another reason for not releasing the 3D CAD model is the fact that it is enormously complicated, incorporating hundreds of individual components (i.e. files) which come together in many subassemblies and finally into several major assemblies. To give you an idea of the size of the complete 3D CAD model of the engine it takes 10 minutes or more to load on a fast computer. When the 2D drawings have been published, a perusal of the likely 50 sheets will indicate the large number of finished parts many of which include two or more 3D CAD elements. Keeping track of all this complexity is just one of the administrative overheads of the project. During the construction of the prototype, we will be seeking to improve the design by such methods as exploring alternative manufacturing methods for components and simplifying the design where possible by merging multiple components into larger single components. The following table lists the 2D CAD drawings as they stand at the end of October 2023. Drawing No. & Name
SHT-A Inside Cylinder Assembly & Details SHT-B Inside Cylinder Details SHT-C Outside Cylinder Assembly & Details SHT-D Outside Cylinder Details SHT-E Locomotive Arrangement SHT-F Tools & Jigs SHT-G Coupled Wheel & Axle Assembly SHT-H Driving Wheel & Axle Assembly SHT-J Mainframes Assembly SHT-K Stretchers & Buffer Beams SHT-L Slidebar & Motion Bracket Assembly SHT-M Engine Bogie SHT-N Trailing Truck SHT-P Inside Rods & Motion SHT-Q Outside Rods & Motion SHT-R Reversing Gear SHT-S Mainframe Details SHT-T Engine Brake Assembly & Details SHT-U Engine Brake Details SHT-V Grate & Ashpan SHT-W Smokebox Assembly SHT-X Smokebox Frame & Saddle SHT-Y Smokebox Top, Door & Chimney SHT-Z Tender Arrangement SHT-AA Platform Plates & Brackets SHT-AB Smoke Deflectors & Details SHT-AC Cab Support Assembly SHT-AD Cab Assembly SHT-AE Cab Plates & Windows SHT-AF Boiler Cladding Assembly & Details SHT-AG Superheaters & Main Steam Pipes SHT-AH Lubricators SHT-AJ Axle Pump & Boiler Feeds SHT-AK Exhaust & Regulator SHT-AL Cab Details & Boiler Accessories SHT-AM Sandboxes, lighting, plumbing SHT-AN Reversing Gearbox Assembly & Details SHT-AP Piping Schematic SHT-AQ Boiler Assembly & Details SHT-AR Miscellaneous Details SHT-AS Tender Frame Assembly SHT-AT Tender Frame Details SHT-AU Tender Wheels, Couplings, Details SHT-AV Tender Brake Assembly SHT-AW Tender Handbrake & Cylinder Details SHT-AX Tender Brake Gear & Details SHT-AY Tender Tank Assembly SHT-AZ Tender Tank Details SHT-BA Tender Bunker, Roof & Cupboards SHT-BB Tender Tank Top Assembly SHT-BC Tender Tank Top Details SHT-BD Tender Handrails, Lighting, & Details SHT-BE Tender Hand Pump & Plumbing SHT-BF Painting, Lining, Decals, Details
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Post by brucevoelkerding on Jun 23, 2023 11:52:11 GMT
something to consider as your List of Drawings grows is - how to manage Drawing Revisions. I have worked for 3 industrial Manufacturers making Machine Tools and each had their own Method to control design changes. The Service Department of one of these Manufacturers would get calls for replacement Headstock Gears from Machines made during WW2. The System used there made finding the correct Drawing simple with use of the Machine Serial Number.
Many times I have read in this and similar Forums issues regarding the correctness of Drawings ("you have the old Clarkson drawings, they were redrawn by..." or something similar). I would suggest that you make a separate Sheet to your General Arrangement (an Excel file - not a CAD file) which lists EVERY Drawing and its current Revision Level.
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Post by masahiraoka on Jun 25, 2023 11:47:34 GMT
Thanks Bruce
yes a very good idea to maintain a master component / drawing file list in a spreadsheet format.
You mighten't be surprised to hear that we already have such a spreadsheet which contains some 2,400 individual components not including nuts/washers/ split pins etc.
again this is another adminstrative overhead which is absolutely necessary to maintain our sanity vis a vis the scale and complexity of the 3D CAD model and 2D CAD drawings
regards Martyn
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Post by masahiraoka on Jul 13, 2023 3:56:04 GMT
hi all here are some drawings showing the complexity and detail for the West Country braking system ciao Martyn  |
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Post by runner42 on Jul 13, 2023 7:51:26 GMT
Hi Martyn,
an interesting two brake shoes per coupled wheel configuration and operated by one hanger assembly. I assume the brakes are steam operated although the actuation is not shown. Good that an isometric view is included.
Brian
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Post by masahiraoka on Jul 14, 2023 7:39:35 GMT
Hi Brian
Yes the double shoe per hanger design was always an interesting feature of both the West Country and Merchant Navy Pacifics.
We've followed the full size design carefully but is does make for lots of parts!
And yes the brakes are steam actuated. if you look carefully at the left hand end of the isometric drawing you can see the steam brake cylinder mounted on top of one of the frame stretchers.
What you're looking at is the non-functional end of the cylinder - the business end is point towards the rear of the engine.
Applying the brakes pushes the brake cylinder piston rearwards and through the connecting arm the brake gear spreader bar (under the stretcher) forwards pushing all the shoes onto the wheels.
ciao Martyn
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twombo
Seasoned Member
Posts: 120 
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Post by twombo on Jul 14, 2023 13:39:35 GMT
This "Clasp" braking, arrangement gains 'power' by the "scissor Action. Ingenious!
In the smaller Scales, can such parts, be laser cut parts or printed?
It is great that you are building the, supporting, dataset according to long range needs. It Certainly is, a matter of Sanity! Retrofiting this, important Structure, is a miserable task! Thanks for the overview, Martyn!
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Post by masahiraoka on Jul 16, 2023 0:02:14 GMT
Many of the brake parts will be 3D printed see below  |
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Post by runner42 on Jul 16, 2023 7:36:36 GMT
Hi Martyn.
plenty of detail and without 3D printing your project design team would have needed to rethink how parts could be fabricated and possibly descope the amount of detail that could be realised. So your model is truely one of the 21st century and not equalled by its peers (as far as I know). I am not au fait with 3D printing so what material is used to produce the parts and what time is incurred to produce a set of parts for the brake gear?
Again congratulations to the team on such an inspirational project and please let them know that their efforts are much appreciated.
Brian
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Post by masahiraoka on Jul 17, 2023 11:00:01 GMT
Thanks Brian
as they say it’s not over till the diva sings! Whilst the 3D and 2D CAD design is essentially complete we still have some considerable way to go on resolving all the production decisions including building the prototype. This process will be an iterative one ie experience in building the prototype will inform refining the design and production techniques.
Once complete though I agree with you that we should have a 21st century project. I’ll pass on your kind thoughts to our team.
As to the details of 3D metal printing material we use stainless steel. 3D printing in metal can’t print in mild steel so if you need another material such as for the cylinders or wheels then you have to revert to casting. Fortunately 3D printing can provide the patterns for casting using a variety of techniques. In some circumstances we are using CNC profile cut flat sheet mild steel and then fabricating complex assemblies.
hope these comments help explain where we’re going
ciap Martyn
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