Discussion in 'Steam Traction' started by Flying Phil, Dec 24, 2018.
I didn't say if they'd be readable!
On GCR 567, Our AutoCAD Version 2006 Drawings exist on an old 2002 Windows XP SP3 HP ze5440EA - Built like proverbial Brick Sh** House, Still going like a steam train.... however backed up on my everyday HP Pavillion g series computer running Windows 10 and AutoDesk True View 2015 (so I can read drawings). Further back-up HP 64 GB USB 'Stick' - also used to transfer drawings to Chief Engineer's Laptop. Not saying its fire proof, but with multiple locations, the chances are the drawings will survive somewhere as .dwg files.....and will be accurate. So long as Microsoft Excel continues, they are listed and revised for reference.
Sadly, although my version of AutoCAD WILL do 3D - the old computer takes ages to create the drawing - slow enough with some 2D drawings 2MB large GA drawings!
As a thought on the subject of old drawings.... when you look at the Old Linen drawings that have been microfilmed and put up as .pdf files - beware.... If the part detail you require is not dimensioned and you think you can scale it - think twice as the scale will vary from the centre to the edge and top to bottom - the only chance you have is to scale something adjacent to the bit you want!!!
Oh! the pattern is safe, in good order (Trefoil are very careful) and can be used for other projects when required.
Even if you have the original linen you have to be careful. Fortunately most of the drawings I've had to work with have been electrical and so not to scale, but I have come across a 'scale' drawing of a section of railway which was out by some ludicrous amount (10m? 100m? I forget now) when compared with a survey between fixed points. Take nothing for granted!
Just out of curiosity, are you generating 2D drawings from an accurate 3D model or simply creating a more traditional set of 2D drawings? I am in the architectural profession so know how technology has changed in that sphere over the last 20 years or so but not so sure about mechanical engineering. Also, if it is a 3D model, is it useful for FE analysis in its raw state? Cheers
I draw in 2D - the 3D is in my head... Having said that - we are entering an age where people cannot read drawings without 3D visualisation. We have had/having some 3D 'Pictures' done from the 2D drawings to show how things go together, and yes for FEA.
I see from an e-mail flyer I found this morning that there are only 4 more Supporters spaces available which will give a place on the first passenger train to be hauled by No.567 (out of 200 which were originally available), so if you want to secure yourself a space, sign up now!
I had a book on the Midland 2P 4-4-0’s for Christmas and whilst reading it another, almost too obvious, question popped into my head. As all original drawings are in feet and inches, do you create new drawings for procurement in the same units or convert to metric? I’m guessing that contemporary UK engineering facilities need everything in millimetres, in which case, are there any issues with rounding up, or down, with regards to tolerances? I know that our friends across the pond still use Imperial measurements so it is possible to get a lot of raw materials and components in those units but that is hardly practical. I’m just curious as I have spent some hours converting original GWR infrastructure drawings (bridges and stations) to metric as part of my day job and wondered what conclusions you came to for an engineering project of this nature? Hope you all had a good Christmas!
Like a lot of things, it all depends... Many organisations are still happy to work in imperial units so are happy to work to existing drawings. Some raw materials are now almost unobtainable in imperial whilst others haven't actually changed at all, only being given a metric equivalent. Steel plate and some sections are now largely metric so getting (say) 5/8" thick plate will be very difficult and you will have to make a choice between 15mm and 20mm. Other sections haven't changed so I'm fairly certain a (say) 203 x 133 universal beam is no different from an 8" x 5¼" UB. Pipe hasn't changed dimensionally so a (say) 40mm pipe is the same as a 1½" pipe. Tube is still commonly available in imperial sizes. I've recently bought 1" OD tube in both copper and steel. Even where imperial materials are still available, it may not be possible to get a direct replacement because of rationalisation over time. Roller chains are still available in the British Standard imperial sizes but try getting hold of some BS 2¼" pitch chain, as distinct from an American standard (ANSI) one.
Yes, the decline in the ability to understand Imperial Measurements.... So, what do we do? Our workshop at Ruddington has volunteers who understand that 25.4mm = 1", that's a start. When we go out to order cut steel, we use Metric plate and Angle Section (as near to the Imperial Size as possible) .... Where the steel is profile cut to shape we give the dimensions in mm - the error of up to 0.5mm is quite acceptable to us.
Cast components are Imperial - Our Patterns are made that way.
I think on "Beachy Head" the frame plates are 30mm rather than 1 1/8" (which would be about 28.5mm). The extra is taken up on the inside; it means all the frame stretchers etc are drawn up to be about 3mm narrower than the originals. Of course, they would have had to be redrawn anyway, so it isn't necessarily extra work, just a case of keeping tabs on everything!
I'm not sure dimensions are necessarily the hardest thing; rather it is that certain processes can't be achieved or have to be done in a different way. Two spring to mind on Beachy Head that I recall being difficult to achieve: one was to put a joggle in the frame behind the trailing axle that just about no-one in this country either could, or was willing, to attempt. The other was beading around the cab look outs, which originally would have been a particular profile of drawn metal, curved to shape. That section was not available, so it has been fabricated from about three different sections.
Happy New Year sees things moving on the Bogie Wheels and Axles - or should I say Push comes better than Shove.
More exiting news with the next newsletter.
And in response to Jamessquared - I drew the Cab - BUT then as the BL group discovered the curved to 'T' Section steel had just been deleted - we will profile cut a plate to the correct curvature and weld on the curved top flat. These things happen - Ho-hum!
Looking forward to the next newsletter -but is that the quarterly one due in March, or are we going to get the monthly updates that were mentioned last year?
Is the project moving quickly enough to warrant a monthly update though? Don't get me wrong, if there's enough tangible progress to support a monthly newsletter I'm all for it, but if on the other hand all that it would tell us would be 'pretty much same as last month' over and again I can't see that it would do much for the morale of us supporters. An occasional extra newsletter, for big news, might be a good move though.
You make a good point J Rob't, but if the project is to keep to it's timescale they will need to make some monthly progress, even if it is only small parts......There are going to be a lot of them!
Yes there are many small parts, Fitted bolts etc (7/8" and 1" Whitworth) that could be done on a bar auto or smaller lathe to assemble the Bogie. Bigger parts are also needed to complete the Bogie and Motion..... Loads more Engineering to be worked out and agreed.
Well a wheely good bit of news - our contractor in Coalville can keep working during this lockdown.
We are all tired of this Virus - but soon we may be tyred of all this?
So pictures of bogie wheels with tyres on axles soon then.....
Just to update this from Legrandanglais on the "GCR Gap" thread.....
...."Unfortunately, the GCR567 Chief Engineer is having to run this EMRT Project oversight - so 567 Engineering management is having to take a back seat - although others in the group continue to manage some sub-contract work - watch this space on BOTH of these Projects....!"
Somethings are hot today in West Leicestershire - but cooling down nicely! What are they? All will be revealed shortly to the Supporters
MainLine Issue 186 Spring 2021 - 1st March will have some good news and pictures ... Supporters will be told before that ...Guess what?
I'm getting tired?.....or should I bogie off?.....
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