Steel beams in G3 - MR Implement Wagon

AndyB

Western Thunderer
A bit of an odd request this - but maybe someone can help!
I'm designing etches for various Midland Railway Implement wagons in Gauge 3 from original drawings (dated 1912-13).
The solebars and longitudes use British Standard Beams ('I' section) - B.S.B.18 (10" x 6") and B.S.B.22 (12" x 6"). BS4 for such beams was first issued in 1903.
I have various post-WWII references, and a 1927 reference for the details of the beam section. All these show that the inside of the flanges were angled at 98 degrees to the web (or 8 degrees to the outside of the flange).
But the MR drawings of the brackets that fit with these beams do not agree with this taper - they come out at more like 4 degrees.
So I'm wondering if the standard sections were modified around WW1 - possibly to save material as part of the war effort?

Does anyone have a pre-WW1 edition of an engineer's reference book (e.g. Kempes, Molesworth, etc) that might contain dimensions of these sections?

I have tried the library of the Institution of Mechanical Engineers - they don't keep that type of book that old. Suggested I might be able to get copy of the old standard from BSI - but that will cost >£30.

Any information, suggestions or leads welcome.

Andy
 

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Bob Reid

Western Thunderer
Andy,

I've a July 1904 copy of the Properties of British Standard Sections - issued by the Engineering Standards Committee (a mix from the various Civil / Mechanical / Naval / Iron & Steel & Electrical! Institutes ) committee's - Inc. D.Bain of the Midland.... anyway, all of the Beams (inc. BSB 18 & 22) show the angle then to be 98 degrees. I did wonder if the Midland were still using beams created with non standard rolls, despite what the drawings say. BR always covered these interfaces on brackets - as the Midland did with "profile to suit"!
 

AndyB

Western Thunderer
Bob - that's really useful confirmation. Thank you.
I imagine it would have been a few years before beams to the 'new' standard became readily available, and the Midland didn't build many wagons using 'I' beams, so maybe the draughtsmen simply did the drawings based on any old stock that was around - with the catch-all note 'to suit' as you observe.
Still I'm left with a conundrum - do I build according to the spec or according to the bracket drawings? Back to look closely at the photos first, to see if it is possible to tell anything from them.

Mike - thanks also for your suggestions.

Andy
 

Bob Reid

Western Thunderer
Certainly Andy, the book makes particular mention of the number of beams etc. that although still produced for a variety of uses were not encompassed by the "standard" I've no doubt it would take many of the mills a long time to render many of the old sizes obsolete - probably when the rolls themselves wore out and orders diminished.

Out of interest, wouldn't the shape of the bracket be relative to the section of the model beam rather than the prototype unless of course you are able to source scale section beams?

Regards.
 

AndyB

Western Thunderer
Out of interest, wouldn't the shape of the bracket be relative to the section of the model beam rather than the prototype unless of course you are able to source scale section beams?
Yes Bob - it will be relative to the model section. But my aim is to reproduce a scale section beam using built-up etch layers. In G3 using 12 thou etches, I reckon I can get a pretty close match to a scale section, whether it has 4 degree tapers or 8! I'll post up the results when I get some shiny brass in my hands.

Andy
 

AndyB

Western Thunderer
In keeping with my tradition of never getting anything done too fast, here we are 4 months later..... with some shiny metal parts.

The first two pictures show a completed longitude and a close up of the end where the tapered flanges can be better seen.
Each longitude consists of 9 parts- the web in 0.018", and the rest in 0.012" brass.
The third picture shows the component parts for each solebar - more complicated due to cut-outs where the axleguards fit.

Due to the curves at each end of the well the tapered faces of the flanges in these areas are conical, so in the flat they have to be curved accordingly. Being able to set the length of a curve using 'arc length' in CAD makes this much easier.

I'm quite pleased with the results so far - the one thing I haven't managed is to represent the fillet between web and flange. I hoped to do this with a solder fillet, but so far it has run everywhere else but in a nice fillet. Can anyone suggest a suitable solder and/or technique for achieving this?

I'll show some of the bracketry that join the beams together in a future post.

Andy
 

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adrian

Flying Squad
I'm quite pleased with the results so far - the one thing I haven't managed is to represent the fillet between web and flange. I hoped to do this with a solder fillet, but so far it has run everywhere else but in a nice fillet. Can anyone suggest a suitable solder and/or technique for achieving this?
It does look good.

As for the fillet I suspect the trick to running a nice fillet of solder in the joint is to get enough heat in quickly to run the soldering iron smoothly along the length of the joint. Given the thickness of the metal presumably getting the heat in is the problem. Not tried it myself but perhaps preheating the frame with a blow lamp before soldering might help the solder to flow a bit better.

Alternatively do your best making a solder fillet and then grind an old needle file into a scraper and radius one corner to make the fillet when cleaning up.
 

Steve Cook

Flying Squad
That is very nice Andy, I like that :)
I'm with Adrian on the fillet front, I would have thought a 80W+ iron and 145degC solder would have got the job done - the challenge will be holding everything in alignment so you can feed in the extra solder and flux as you wipe the iron down each joint.
Steve
 

jamiepage

Western Thunderer
Very much looking forward to one or two of these, Andy. Excellent stuff. Were the wheels 2ft 8.5in diameter, or 3ft 2in on these wagons? If the smaller, do suitable G3 wheels exist?
Jamie
 

AndyB

Western Thunderer
Thanks all for your comments and suggestions.
I've used my home-built resistance soldering unit for construction so far, and using solder paste containing 2% Ag. Getting sufficient heat into the job has not been a problem, and the way the paste flows into small gaps is excellent but no good for large fillets. Steve - I think the 145 solder may be the key. I have read various bits of information about the properties of different solders, but they haven't stuck sufficiently in my head yet!
For alignment, I've made a simple jig (3 blocks of steel, 2 small G-clamps and a bit of wooden coffee stirrer) which has worked well.
Jamie - wheels were 2ft 8.5in diameter. Slaters do a 2' 9" disc version (produced for the GRS W&U coach) of which I have a sample. I've had discussions with David White about a new 8-spoke centre using this same rim.
This is really a test piece to see what could be achieved (pushing the boundaries a bit further?).
I don't plan on producing a full kit for this model (not commercially viable) but will do sets of etches on request. Lets talk more at the AGM in Feb (assuming you'll be there).
Andy
 
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