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Post by masahiraoka on Apr 5, 2020 13:16:33 GMT
Thanks Adam
all very useful tips. So far we’ve found the dimensional characteristic of the stainless steel prints to be essentially perfect and the brackets only need the very lightest of dressing up before use. We’ve also designed it so that none of the holes in the brackets have to be tapped. So so far all good. Some shots of the assembled chassis are coming soon as well as the castings of the cylinders and wheels.
I’ll discuss your suggestions with Phil.
regards Martyn
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Post by masahiraoka on Apr 7, 2020 3:58:38 GMT
Inside Motion Bracket
• The conventional drawing below is an extract from the original BR dwg no. W11616  • and this is resultant 3D CAD design  • and the finished 3D printed bracket  
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Post by masahiraoka on Apr 8, 2020 22:40:45 GMT
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Post by masahiraoka on Apr 11, 2020 2:24:41 GMT
Outside Slide Bar Bracket
• The conventional drawing is an extract from the original BR dwg no. W11698  • this is the resultant 3D CAD design  • and the finished pair of 3D printed brackets    • the next posts will cover the cylinders and wheels
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Post by masahiraoka on Apr 12, 2020 18:53:24 GMT
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Post by Oily Rag on Apr 12, 2020 22:15:28 GMT
"Building a nearly completed 3½"g streamlined Duchess, and an early stage 3½"g LNER W1-like 6 cylinder geared Pacifc and a 3½"g rebuilt West Country"
Have you pictures of the Duchess or link to an album ?
I would be most interested.
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Post by masahiraoka on Apr 12, 2020 23:34:28 GMT
Darrell
apologies but i haven't created a thread for the Duchess but i'll consider doing so once i've up loaded the bulk of the West Country material in a couple of weeks
ciao Martyn
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Post by runner42 on Apr 13, 2020 23:23:56 GMT
Hi Martyn,
a most interesting project, that I am following most avidly awaiting each installment. There are many questions I have but suffice to ask at the moment is the 3D printer output used for creating a wax lost casting? Additionally, what type of fasteners do you intend to use, since you are endevouring to create the threads in the casting without the need for using taps? Is it possible to 3D print the fasteners so in reality you can use a prototypical one, but I see problems in going down that path?
Brian
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Post by masahiraoka on Apr 14, 2020 4:44:16 GMT
Hi Brian
I’m glad you’re enjoying the project.
With regard to the brackets we 3D print directly in stainless steel from the 3D CAD file ie there is no intermediate 3D printing in plastic.
With all the brackets we have designed them so that they use 10 BA nuts and bolts as fasteners. We have ensured that no tapping for 10BA fasteners is required which would be a nightmare in stainless steel.
In later postings you’ll see photos of the assembled chassis clearly showing these bolted joints
The cylinders and wheels are however cast by a foundry using a conventional “lost wax” type process but utilizing 3D printed patterns we print in plastic rather than wax. The foundry then melts these out ie they’re lost in the process.
Hope this answers your questions.
Martyn
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Post by coniston on Apr 14, 2020 22:33:02 GMT
This is a phenomenal project utilising current technology. It is no wonder we don't see many WC, MN or BoB class locos in miniature. Malcolm Frost, one of the founders of MJ Engineering sold the castings for Wilsons Ariel design and gave us a talk at the club one evening including how the centre cylinder casting was produced. The pattern for that was a real work of art with all the cast in passages, I cant remember the number of core boxes used but it was mind boggling.
Cant wait for your next instalment.
Chris D
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Post by masahiraoka on Apr 15, 2020 5:37:17 GMT
Chris i'm glad your enjoying our project regards Martyn Outside cylinders
• The conventional drawing is an extract from the original SR dwg no. W5451 • These have been redesigned slightly to be reversible ie neither left nor right-handed unlike the full size      |
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stevep
Elder Statesman
Posts: 1,073
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Post by stevep on Apr 15, 2020 18:09:29 GMT
This is a phenomenal project utilising current technology. It is no wonder we don't see many WC, MN or BoB class locos in miniature. Malcolm Frost, one of the founders of MJ Engineering sold the castings for Wilsons Ariel design and gave us a talk at the club one evening including how the centre cylinder casting was produced. The pattern for that was a real work of art with all the cast in passages, I cant remember the number of core boxes used but it was mind boggling. Cant wait for your next instalment. Chris D I have also been the recipient of that talk. Utterly brilliant. |
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Post by masahiraoka on Apr 17, 2020 5:10:03 GMT
Driving Wheels
• The conventional drawing is an extract from the original SR dwg no. E30846 • the photo shows the driving wheels cast in steel from 3D printed PLA patterns also shown • Currently because the wheels are cast the "undercut" on the wheels cannot be included and a flat plat will have to be brazed onto the wheel to achieve this important distinguishing feature • but we experimenting with 3D printing the wheels directly in steel which would enable the undercut to be included from scratch    
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Post by osiris09 on Apr 17, 2020 5:14:17 GMT
Looking great. The plate on my one is riveted on to the back of the wheel but would love a new set that were 3D printer and completely accurate.
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Post by masahiraoka on Apr 20, 2020 12:53:22 GMT
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Post by masahiraoka on Apr 22, 2020 23:26:45 GMT
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kipford
Statesman
Building a Don Young 5" Gauge Aspinall Class 27
Posts: 575 
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Post by kipford on Apr 23, 2020 6:35:33 GMT
Martin
Hope you do not mind but where are you getting these parts printed and what sort of cost are we looking at? It is the question everyone wants to know but does not want to ask. Seriously I have a couple of project items looking for this.
Dave
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Post by masahiraoka on Apr 23, 2020 15:02:41 GMT
Dave
We’re still trialing a number of 3D metal printing services and foundries across Australasia trying to find those that can consistently deliver good quality at a reasonable price in tiny volumes. In addition we’re still making our minds up about the exact manufacturing technique of tricky components such as the wheels.
With regard to cost the brackets and stretchers shown in the photo in my last post cost, if I remember correctly, between 100 and 200 pounds each so approx. 1500 pounds for the set of 9 shown. However we expect that the cost of 3D metal printing will come down quickly over the next few years. I have material prepared on this topic so will make it my next post.
The big investment is in the time taken to design these components correctly. And it is not a matter of simply turning the original full size SR/BR drawings into CAD drawings. There are many many decisions along the way about what happens when you scale the design down to 1/16 including issues of rational sizing, manufacturability of the components, constructability of the loco once you have the finished components, and modeling the details and aesthetics of the full size loco without adding unnecessarily to cost.
I know that this doesn’t fully answer your questions but we’re still in the middle of the design development phase seeking our own answers to the same questions.
regards Martyn
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kipford
Statesman
Building a Don Young 5" Gauge Aspinall Class 27
Posts: 575
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Post by kipford on Apr 23, 2020 22:14:27 GMT
Martyn Thanks for the reply most interesting and not as expensive as I thought. I agree with you the biggest investment is and should anyway be the upfront engineering. I spent all my working life as an engineer fighting the bean counters over the amount of engineering required to take a product to market. I say engineering because as you elude it is not just about producing a 3D model and drawings, in my industry, Aerospace the design phase was probably only about 25% of the total engineering effort. Anyway I recently completed designing and productionising a 4 mm scale kit of the LNWR 4 ft Shunting Engine for a UK kit supplier. As I have all the research data and it would make a lovely alternative to the ubiquitous Pug. So I am in the early stages of designing a 5" inch gauge version and currently looking at where I can use laser/water jet, 3D printed waxes for lost wax castings and also additive manufacture. I have extensive laser/water jet experience and my Aspinall project will have over 300 laser cut parts in it when finished, but 3D printing with metals I have only tried once at work before I retired with Titanium so any feedback on your trials and tribulations would be very interesting. PS I also work with 12"/1ft Steam at the Mid Hants Railway. One project you may be interested in that I am currently involved with is the first centre cylinder for an un rebuilt WC/BB to be cast since BR days. This involves a 3D CAD model of the cylinder, then sand casting using a poly pattern as the original patterns are long gone and new wood patterns would be prohibitive. We have had issues (which I cannot go into here) and are now on modified poly pattern hopefully going to casting in the next few weeks, COVID-19 permitting. I only have a few photos of the first variant of the poly pattern but they give you a sense of the complexity of this part, the most complex casting I have ever seen and more so than the rebuilt version. Keep it all coming, How about a proper unrebuilt, with chain valve gear next, you are halfway there. Dave W5450 BR Drawing  W5450 Inside cylinder 16 3eighths x 24 by Dave Smith, on Flickr Poly pattern  IMG_0987 by Dave Smith, on Flickr  IMG_0980 by Dave Smith, on Flickr |
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Post by masahiraoka on Apr 24, 2020 0:45:03 GMT
Dave fantastic photos pf the poly pattern of the full size inside cylinder - it looks like a giant dinosaur skull! I can send you a very clean version of SR drawing no. W5450 if you want - PM me your email address. I sent copies of all the cleaned up versions of the 750+ drawings we've purchased back to the NRM for their future use and sale to customers. Not quite sure what they've done with them since. re an as-built version of the West Country that is possible, we're certainly considering it, but we'd probably use the Stephenson's valve gear from Len Gillet's Anchor Line described in my post of 30th March I have one more post on components before I post the material on costs. Ash Pan & Hoppers• the conventional drawing is an extract from BR drawing W10300 for the West Country Outside Ashpan  • these photos show the PLA 3D printed ash pan, hoppers and grate. we haven't printed these in metal yet    |
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