7mm Gladiator Royal Scot build

[Tim2014]

Hang on, isn't annealing in brass done by heating/allowing to cool slowly?

 

I thought quenching was for re-hardening?

 

Just checked and it seems you can do both. My old metalwork teacher wouldn't have approved.

I'm no expert, but I think annealing is a general term for a heat treatment that gives desirable properties to a material, whereas quenching is always sudden cooling (again to create a desirable property in the material). I'm sure I use the terms too loosely, any metalwork I know is all self-taught (though I know a very little about metallurgy from a Chemistry degree a long time ago).  At any rate, it seems brass is rather easy to soften (given sufficient heat in the first place) and the rate of cooling is not especially critical..  Ferrous metals are apparently very different and I've heard that unannealed glass (eg if spilt in a glass factory) is incredibly dangerous - liable to explode from the slightest vibration which releases the pent up stress from the sudden cooling which annealing removes.  In most materials, long slow cooling creates larger crystals, and it's the crystalline structure (it's molecular geometry and composition) that determine the bulk physical properties we get to work with.  Those properties aren't always intuitive!

 

Anyway, back to brass for models, I tried to get some 1.5mm brass sheet really hot with my (butane) blow lamp and couldn't get it past dull red, and cooling it fast or slow, it was still WAAAY harder than even a plastic, much less a wax, though definitely easier to bend than before it was heated.  The same blow lamp melted thin, narrow sheet almost instantly.  So here, I think is the problem: what works on a piece of 1/32 brass rod is not going to have the same result on a 0.8 mm thick sheet of brass. What works on a 4mm cab roof (1" square), may well not work on a 7mm cab roof (4" square) if the same heat source is used. The heat loss from metal outside the flame area will be dramatic and that will limit the actual temp you can get any particular area to be if the piece is larger than the flame.  I personally think that going by the brass colour for a large piece isn't going to be very helpful - it's likely to be a surface property, and not necessarily reflective (s'cuse the pun) of the bulk of the material.  Again - a short length of wire would behave differently to a large sheet.  I can tell you that still air is a very good insulator, so working on a calm day, or indoors, would be very different from a draughty area.  Using a sand bed would definitely be a good idea to even out the heat.  My experiments today were outdoors on an old block of plaster and it was very windy.  With the IR laser thermometer, the highest reading I could get was ~450 C, but the brass sheet (smokebox) was red hot (just dull red), and it was definitely hot enough to soften the brass (I kept it near red heat for a few minutes, then quenched in water) and it has begun to roll nicely. I stopped because I want to clean it up with a scratch brush and rivet it before completing the rolling  I will report back in due course.

[Tim2014]

Here's the brass smokebox after heat treatment, no cleaning up.  This was heated to *just* under red heat. I could see a very dim red glow against the daylight and I spent a good few minutes spreading the heat around, concentrating mainly on the middle areas figuring conduction would take the heat out to the edges.  You can 'sense' the uniformity of the temperature of the sheet from the way the flame changes the colour of the sheet as you move the blow lamp around.  I quenched this under water too.  It was quite distorted immediately afterwards (no pic, sorry), very definitely not flat anymore.  But a little gentle rolling with my battery on the sheet and the sheet on the arm of a comfy armchair resulted in the beginnings of a smooth curve as shown:

This first pic shows the remains of some permanent marker/sharpie marks. I was using them to mark out which half etch rivets to punch, but then read on a jewellery site that marker pen is a good guide to annealing temperature.  Certainly, the lines withstood some significant heat before disappearing and assuming they disappear at a certain temperature, are really rather useful for a large piece like this, not to mention keeping the brass cleaner too.  I did heat this beyond the 'disappearing temp' though.

 

I then stopped rolling to clean up the outside and rivet it:

 

Continuing rolling I found eventually that using the battery as a roller was too awkward and I took to gradually pressing the metal around it, moving the pressure point after each small bend to keep the radius of the curve constant and match both ends of what soon becomes a cylinder:

 

The battery is a slightly smaller diameter than actually required so I wrapped one edge under towards the end (being careful not to press the other face down hard and risk distorting the rivets.  When finished the 'spring' of the smaller diameter holds both edges together (apologies for the dodgy photo):

 

I was really pleased with this, until I trial fitted the smokebox front casting.  Without having cleaned it up properly, I think that there will be ~1 mm gap in the smokebox if I use the casting 'as is'.  Pretty sure that has been a problem in some other builds, so I will hit the search engines.  Since I want an opening smokebox anyway, removing the center of the front casting and reducing it's diameter could be an option.

 

[Tim2014]

Update:

Exactly 1 mm gap when cable tied together in approximation of final positions.  It needs that gap/diameter to match the front of the boiler, so I guess I fill the gap? It seems unlikely that two etched end plates and the casting are all the wrong diameter by the same amount...

 

Bear in mind this is all just 'resting', nothing is soldered or bolted so the odd half mm out of alignment might be visible.

 

And yes, that photo is 90 degrees out...

Edited September 6, 2015 by Tim2014

[Tim2014]

I missed out the boiler build.

In comparison to the cab and firebox, it was a doddle.  The boiler is pre-rolled – it would be a *LOT* harder without that nice touch. Here are the parts ready to go together:

 

Apart from a thoughtless application of the iron to tidy up a seam at the bottom of the boiler, things were straightforward.  Cable ties aren’t ideal though, the heat makes them stretch and I resorted to some twisted wire to really clamp down and get a nice cylinder, I know there are some nice purpose-designed clamps you can get for this, but twisted wire worked well for me.  There was a small gap at the bottom at the firebox end and the ends meet at the smokebox end.  This area is hidden but I was able to fill it with solder anyway. Presto, one boiler:

 

One thing I noticed may be worth mentioning. There are etched alignment marks on the end plates and inside the boiler edges. The first end plate is easy to align as you can see what you are doing. The second of course is hidden inside the boiler. I had (lazily!) not cleaned the ends of the boiler up and as it happens there is a fret join exactly over the alignment mark which can be used in lieu of the the etched alignment mark to tell you exactly where the top of the boiler is so you can then align the end plate exactly.  Once assembled, you can file the raised cusp off. A bit of luck!

Edited September 6, 2015 by Tim2014

[Tim2014]

Hi Tim,

 

You really do need to get a blow lamp or a gas hob to spread the heat more evenly, as the small flame you are using is leaving the metal in various stages of strength and stresses if you get my drift. It is OK to have a little bit of spring as you press and solder the sheet around the former, but you do not want to have to use to much force in case of failure later on in the build or even once painted and running.

 

HTH,

 

Martyn.

Wise words! I decided to tear it down, anneal it properly and reassemble. Even as I went to do it I found one lower corner had given way.  I'll edit the original post.  The result is not very noticeably different externally (though the bends are smoother and more complete and it does look better to me), but there is a huge difference in how much stress is pent up in the finished assembly and the whole process was much simpler with properly annealed metal.  Thanks Martyn.

[david.hill64]

Annealing, quenching and tempering.

 

Annealing is done to soften a metal by heating to a temperature and time that allows the crystalline structure of the metal to reform after being deformed for example by cold rolling. You can either air cool or cool in s furnace. In the case of brass you can cool it quickly by quenching in water without having a significant effect on the annealing process.

Steel is a different animal. Unlike brass, iron or steel adopts a completely different crystal structure at high temperatures. Annealing and cooling allows an orderly transition between structures with the result being a soft material. Quenching from high temperatures attempts to lock the structure in an unstable state and a hard brittle compound forms. Tempering involves reheating to a temperature below the transition temperature which allows partial restitution of the structure and a strong material - steel. The metallurgy of iron-carbon is complex.

Edited September 14, 2015 by david.hill64

[Tim2014]

Annealing, quenching and tempering.

 

Annealing is done to soften a metal by heating to a temperature and time that allows the crystalline structure of the metal to reform after being deformed for example by cold rolling. You can either air cool or cool in s furnace. In the case of brass you can cool it quickly by quenching in water without having a significant effect on the annealing process.

Steel is a different animal. Unlike brass, iron or steel adopts a completely different crystal structure at high temperatures. Annealing and cooling allows an orderly transition between structures with the result being a soft material. Quenching from high temperatures attempts to lock the structure in an unstable state and a hard brittle compound forms. Tempering involves reheating to a temperature below the transition temperature which allows partial restitution of the structure and a strong material - steel. The metallurgy of iron-carbon is complex.

Thanks David - very clearly put.  A little OT and belated (Tim's not known for having his finger on the pulse!): congrats on the purchase of this brand of kits, I hope you will be keeping the late LMS/BR themed ones going, but I have to confess my next will be a DA Jubilee and my pocket money won't stretch to another for a year or two... or 3 or 4 the way the AuD is going....  I know it's my first, but I'm very impressed with how the bits fit together in spite of my lack of skills - for instance 'out of the box' the complex shape of the firebox bottom is a near perfect match to the equally complex shape of the footplate and splashers. I've had none of the major problems that I've seen plague some other (more recent and probably less iterated) kits on this site.  It was with much trepidation I embarked on this journey, and I could not have got even this far without the encouragement and help of folk on this site, but I am sure the design of the kit is also a major factor and I now feel confident I'll get a decent looking, decent running loco, even if I can't match the efforts of some of the awesome craftsfolk on here.

[Tim2014]

I was going to upload the following yesterday but I think I crashed the site...

 

I've spent a good few hours pondering the semi-finished outline of footplate, cab, firebox, boiler and smokebox and how I get them to fit together the way they should. The uneven gap between the cab and firebox is easily fixed as there is excess material which overlaps the rear former, but I held off in case I needed to 'rotate' the whole assembly to lower the smokebox down onto the footplate (clockwise in relation to this view):

 

In fact the bottom of the boiler is parallel with the footplate and I think the firebox 'slope' is right when bolted to the boiler but I'm convinced the boiler currently sits too high on the footplate. The instructions say 'parallel and just above the footplate' although there is a nice, near 1:1 scale diagram (though it doesn't claim to be) 2 pages later which implies the gap is actually 1mm or less. I've been unable to discern any daylight in any prototype pics which supports the idea that the gap should be pretty small.  Nor do I know how close the tops of the splashers are to the boiler on the prototypes.  I have a good 4mm or so between boiler and footplate having done nothing but bolt each section together, and about the same between the splasher top and the boiler side:

(I really like that last photo because to me the unmistakable shape of a "Scot" is emerging)

 

Concluding it's not right yet is much easier than figuring out the best way to sort it out.  I could file away the splashers to allow everything to drop into the gap.  The inner face of the splashers is 'off the etch' and they protrude around 1.5 mm into the central gap in the footplate.  The parts of the two rear splashers where they contact the firebox would need careful fettling, but I can't see any real problems doing that.  Any small gap between splasher and firebox in the horizontal will still have firebox behind it - I'm planning a removable assembly from firebox forward...

 

Or I could file away the lower firebox edge as per the instructions.  But here I'd be working along a much longer length of metal and I don't think there is anything to hide any mistakes by covering a gap between splasher in the vertical and firebox.  Now I've written it down, the first option seems to make the most sense.  Anyone want to chime in before I start taking off metal I can't put back?!

 

These show some of the complex mating points between the various bits, pretty good fit considering I've done nothing but take a little off the N/S notches in the front and rear firebox formers to allow the firebox to drop down onto the splashers:

 

I'm fairly sure that the W/M casting that supports the smokebox is too high off the footplate too since everything is parallel to the footplate. It should be fairly easy to sort that out now - and I hope it was a smart move breaking with the instructions as they suggest fitting it to the footplate before commencing work on the cab etc, but that would make lowering it by filing the lower face impossible without desoldering it.

 

I also hope the loco is sitting too high on the footplate. I inadvertently cut the new 'right' CSB springs from the wrong piece of piano wire and they are too thick to allow the right deflection, the footplate should go down another 0.5 mm (ish) when the correct, softer spring is in there.

[3 link]

Hi Tim,

 

She's coming together nicely, and now has that look and shape of a Scot. Tim please do not take this as criticism but in my opinion the top front of the smokebox ( going towards the boiler ) is far to high and the gap between the firebox and cab will probably disappear if you tilt the firebox downwards. It could be just the camera angle or even my dodgy eyes .

 

ATB,

 

Martyn.

[Dave Holt]

I think you are right that the model boiler is sitting high. The underside should be just above the running plate.

On the prototype, the top of the running plate is 6'-3" above rail. The boiler centre line is 9'-31/4" and the small end of the boiler cladding and smoke box are 5'-91/4" diameter. I'll leave you to work out the height of the underside of the boiler and the gap to the running plate.

Dave.

[phixer64]

Simply stunning

 

Regards Jeff

[Tim2014]

Hi Tim,

 

She's coming together nicely, and now has that look and shape of a Scot. Tim please do not take this as criticism but in my opinion the top front of the smokebox ( going towards the boiler ) is far to high and the gap between the firebox and cab will probably disappear if you tilt the firebox downwards. It could be just the camera angle or even my dodgy eyes .

 

ATB,

 

Martyn.

Thanks Martyn, I appreciate the input and post here to get constructuve feedback just like that. It's definitely not the camera angle or your eyes

I did consider titling the firebox down, but the front and end plates on it are square, and the curves at the lower end of the wrapper seem to match the splashers with the angle they are at so I think a lowering keeping the whole assembly parallel to the footplate is in order.

[Tim2014]

I think you are right that the model boiler is sitting high. The underside should be just above the running plate.

On the prototype, the top of the running plate is 6'-3" above rail. The boiler centre line is 9'-31/4" and the small end of the boiler cladding and smoke box are 5'-91/4" diameter. I'll leave you to work out the height of the underside of the boiler and the gap to the running plate.

Dave.

Thanks Dave - that's going to be really helpful, I will convert tonight and get transfer the dimensions to the model.  The slope of the firebox is a bit of an unknown, but I reckon I'll be able to get a good enough angle from the beloved long distance pics the official photographers seemed to like. No good for close detail, but should be scalable for my work.

 

You wouldn't happen to know a source of scale drawings would you? They'd be really helpful and the NRM website defeated me!

[Grasshopper John]

Coming along nicely Tim.

 

John.

[scot6p]

Hi Time, your building looks good I have a rebuilt Scot but mine is a David Andrews one. Unfortunately there is no 7mm scale drawings but there is some 4mm scale drawings which might help if you can rescale them. Also Royal Scot is now running (dont know where) if you can get there it would good to see it. If I can help let me know.

 

Len

[Guest Isambarduk]

"Unfortunately there is no 7mm scale drawings ..."

I do not have a copy now to look but I believe that LMS Locomotive Profiles No.1 The Rebuilt 'Royal Scots' Wild Sawn Paperback – 1999 By Hunt David & Essery Bob James Fred has GA drawings.  If they are like others in the series, they will be to about 12mm/ft but it is easy to scale from them (and many dimensions are given).  David

[KalKat]

Is this any help https://www.google.co.uk/imgres?imgurl=http://i320.photobucket.com/albums/nn340/kevsmith/RoyalScotrebuilt.jpg&imgrefurl=http://trainboard.com/highball/index.php?threads/royal-scot-46115-scots-guardsman.49733/&h=320&w=638&tbnid=2P6ikI5tePmN-M:&docid=xLIyxfL2FtQTVM&ei=tf_3VYgGwrJpu7q9yAI&tbm=isch&ved=0CG8QMyhFMEVqFQoTCMi0nsz2-McCFUJZGgodO10PKQ ?

 

From http://trainboard.com/highball/index.php?threads/royal-scot-46115-scots-guardsman.49733/

[dikitriki]

Hi

 

Royal Scot is at the SVR this coming week end for the gala.

 

Richard

[scot6p]

Anybody going to see this?

 

Len

[Tim2014]

"Unfortunately there is no 7mm scale drawings ..."

 

I do not have a copy now to look but I believe that LMS Locomotive Profiles No.1 The Rebuilt 'Royal Scots' Wild Sawn Paperback – 1999 By Hunt David & Essery Bob James Fred has GA drawings.  If they are like others in the series, they will be to about 12mm/ft but it is easy to scale from them (and many dimensions are given).  David

Ah yes, THAT book! I've been trying to get hold of it since I started the build, so far to no avail.  Apparently a complete reprint is due out soon so everyone with hoarded copies should get them on ebay asap

[Tim2014]

Hi Time, your building looks good I have a rebuilt Scot but mine is a David Andrews one. Unfortunately there is no 7mm scale drawings but there is some 4mm scale drawings which might help if you can rescale them. Also Royal Scot is now running (dont know where) if you can get there it would good to see it. If I can help let me know.

 

Len

As Richard pointed out, it's at the SVR this weekend (17-20th). I would try and get there myself, but there is a small matter of two intercontinental flights and a not-insignificant amount of hard-earned that rules it out (I'm in Perth, Western Australia!).  If anyone does get there and can get pics of any of my 3 areas of interest:

1. Overhead pics of the firebox/boiler/dome area, esp the firebox to boiler transition

2. Footplate height shots under the boiler

3. The splasher to firebox junctions

I would be very, very grateful.  I'm hoping my Dad can get over there with a camera but apparently he might have other things to do (outrageous)!

 

How's your DA one coming along Len?

3rd edit - must think before posting!

I don't mind scaling the dimensions, *ANY* high res scale drawing would be fine if you know of any source...

Edited September 15, 2015 by Tim2014

[Tim2014]

Is this any help https://www.google.co.uk/imgres?imgurl=http://i320.photobucket.com/albums/nn340/kevsmith/RoyalScotrebuilt.jpg&imgrefurl=http://trainboard.com/highball/index.php?threads/royal-scot-46115-scots-guardsman.49733/&h=320&w=638&tbnid=2P6ikI5tePmN-M:&docid=xLIyxfL2FtQTVM&ei=tf_3VYgGwrJpu7q9yAI&tbm=isch&ved=0CG8QMyhFMEVqFQoTCMi0nsz2-McCFUJZGgodO10PKQ ?

 

From http://trainboard.com/highball/index.php?threads/royal-scot-46115-scots-guardsman.49733/

Yes! That was useful, I'll check a few other dimensions, and I really enjoyed the video. Lovely!

[Tim2014]

Using Dave Holt and KalKat's dimensions, I think I need to lower the boiler by around 2.5 mm. I've not got a good datum for the smokebox center now (oops, cutting out the front of the casting will do that), so I will recheck this, but I think it should be 64.71 mm from rail head to center of smokebox.  I have 67.5 +/-1mm.  I will get it on some track and check it properly tomorrow, guesstimating with the wheel flanges included doesn't help.

 

And the footplate is 44.5 mm (ish) on the model, and should be 43.75 mm by my calcs.

[Tim2014]

Hi

 

Royal Scot is at the SVR this coming week end for the gala.

 

Richard

Hi Richard, Thanks for stopping by.  Can you spare time to tell me whether you filed the inboard edge of your splashers in line with the footplate based on prototype info, or just because it seemed logical? Mine still protrude into the footplate cutout by a little and filing them to in-line would help drop the firebox down and hence lower the boiler so it seems like a good way to go...

[scot6p]

Hi Tim,mine one has stopped for a while as I have other things do. I will check to see if I have some drawings and let you know.

 

Len