7mm Gladiator Royal Scot build

[Tim2014]

From triumph to disaster (and back again now, I think!). While working on the second steam pipe assembly the first one detached revealing an obvious dry joint. Time for Ozzy's 'forkin bigger bit': out came the 80W monster and some serious heat.  I was a little worried about everything else falling apart, but all was good (100C low melt solder and keeping iron contact times down).  It's been a while since I soldered whitemetal so I'd obviously forgotten what little I'd learnt and was being overcautious. Mind you, better that than trying to re-cast the white metal

 

Next up, the smokebox support, you can clearly see the two finished lower edges of the steam pipes.

The smoke box saddle was pretty straightforward, but I do recommend a little care - it's a big piece, but very thin in the middle.  I got the iron bit inside the smokebox opening to get some heat onto the brass from the inside and it's very easy to melt the casting completely, it must be no more than 1mm thick at the thinnest point!  You can see that distortion in the second pic.

 

And now, here's what the front end looks like all bolted together.

Duncan's lovely pics on the previous page suggest to me that a chunk of footplate should really be removed to reveal my non-existant inside motion, so I probably won't (!):

And the famous boiler to footplate gap is about 0.8mm in the end, but I have +/- 0.5 mm variation with my dodgy smokebox rolling and a slightly lower boiler at the firebox compared to the smokebox, but it'll have to do, I don't think anyone will notice once the footplate 'clutter' is in place.

Edited March 2, 2016 by Tim2014

[Tim2014]

Attaching the firebox cheeks is pretty straightforward, and I just needed a bit of solder to fill the gaps – one of my castings wasn’t quite square:

[Tim2014]

Next up is a stage that has been bothering me ever since I decided to make the boiler and firebox assembly detachable from the cab - the firebox beading.  Obviously I don't want lots of gaps so a good flush fit along two separate pieces is vital. That wouldn't be that hard, except in my case I need the solder to attach only to the beading and one other part: either the firebox, or the cab.  I was tempted to solder the beading to the firebox since that is the most complex shape and I figured I could then gently bend the beading to fit the cab, but in the end I decided that getting a truly parallel finish to the cab with that method would be really hard, maybe impossible, so opted to solder the beading to the cab so that the firebox has a nice recess to sit into.  The only challenge is matching the beading shape to the firebox to avoid nasty gaps. And not soldering the firebox to the beading or cab!

 

I tinned the mating side of the beading, then got the sharpie marker out and heavily blacked the edges I didn't want solder to get onto:

 

I tacked the top of the beading in place and then did a couple of other spots along the side.  The beading was a little on the large side so the sides are held in under a bit of compression, that makes it a tricky operation as you have to get the heat in and then push the beading into place (I used a pointed file end for that which is probably bad but there’s not too much heat in there to affect the temper).  After getting the beading tacked on it was ‘hold my breath time’ as I undid the cab to firebox bolts to see if it would come apart. Sure enough, it was soldered together, but some gently wiggling made the ‘bled’ solder joins to the firebox fail and Tim was happy again. In hindsight, annealing the beading would probably be a good idea.

 

Then it was just a case of gradually working round the beading making sure there’s never enough heat for it to spring back into its natural shape.  Here’s the finished job, adding the ejector plate cover is easy in comparison:

 

There is a small gap on the RHS of the photo – although I *thought* I got the piece trimmed, after tack soldering the top in place I realised that side needed a bit more off the bottom.  The only way I could see to do that without stripping all the solder off and starting over was to gently lever the beading away from the cab side, place a jewelers screwdriver behind it to give enough room to get a circular saw blade very carefully into it to remove enough material – obviously I got a little too much off, but it filled with solder and that corner is going to be pretty hidden in the end.  Moral: get it right *before* you solder J

As to why the firebox got joined to the beading, well, the flux I use is alcohol based and a great solvent for the sharpie.  Even though I tinned the beading, I didn’t tin the cab and needed more flux than I would have liked to get the beading to tack to the cab front.  A ‘proper’ solder mask would definitely be a good idea here, you could very easily join all the pieces together, I consider myself lucky!

Edited March 19, 2016 by Tim2014

[Tim2014]

Now why is it that the things that you think are going to be easy end up causing so much grief? The splasher beading seemed pretty straightforward, but they are thin, flimsy etching and so I took great care filing the edges smooth.  But immediately they were off the etch, a trial fit showed the rears were a bit too long to neatly come up to the splashers.  With hindsight, way back when I added the splasher tops, I suspect I should have taken them onto the top of the footplate rather than tuck them under.  Rather than try and fiddle with the splashers themselves, II decided to shorten the beading with a judicious circular saw cut using the minidrill.

 

Soldering them to a scrap piece of etch held them in place and minimised distortion during the cutting process:

 

The saw cut was exactly the right thickness after desoldering and cleaning the edges up with a file. Then it was just a case of soldering the larger edge in and then nudging the small piece up to it. There is a small join, but it’s barely noticeable, and surely better than the 1mm+ gap that would have been between the beading and the splasher top:

 

The front and middle beadings were as easy as I expected, going on with no trouble at all.  I tinned each beading and sweated it onto the footplate, I haven't been using that technique as much as I should, I'm amazed at how little solder you actually need to make the joint.

[Tim2014]

Firebox washout plugs were next.  A lot of holes need opening up and I used a cutting broach to open them up to ~1mm, then pin drills to take them to ~2mm.  I was worried the regular pitch might be affected, and sure enough one side is better than the other, but I don’t think there is anything I can do about it now (edit: I suppose I could desolder and cut the piece in two to realign?).

 

Another newbie problem I have are small ridges around the edges of the enlarged holes. They aren’t obvious, but you can feel them with a finger and they might show up when painted. Any recommendations? I can’t think of anything that would remove the lip without creating a chamfer which might be more noticeable.

 

The upper rows of plugs are all on a single strip of brass and need quite careful alignment. I didn’t have a suitable clamp, but hit on the idea of using a pair of rare-earth magnets I had lying around.  They proved perfect, clamping the piece firmly against the firebox.  The only danger is they *very* strongly attract the tip of the iron if you get too close, but once you are aware of that, they are great as they take up so little room inside what is quite a cramped space. How anyone builds locos in 4mm and N I do not know! Respect…

[N15class]

Looking good. It is always a good idea to deburr enlarged holes. The easy way is to use a drill bit at least twice the size hole, with light pressure rotate it with your fingers, it will put a very light chamfer into the hole. paint will also stick better as paint than it does to a sharp edge.

[Guest Isambarduk]

"The easy way is to use a drill bit at least twice the size hole, with light pressure ..."
 
I agree but, for anything above about 4mm in diameter, I use one of these; there is much less danger of 'digging in':
 

David

[Horsetan]

.....How anyone builds locos in 4mm and N I do not know! ...

We just use a little less solder!

[3 link]

We just use a little less solder!

And have good eye sight and small fingers : )

[farren]

No just burnt fingers

[Tim2014]

Thanks for the humour, much needed I feel!

 

I tried the 'double sized drill' method on the single washout holes (as recommended by Peter Cross) and it worked well, no ridge and a barely visible chamfer. I had tried a countersink bit a bit like Isambarduk recommended, it was probably a bit oversize for the washout holes though.  I think the cutting broaches may have 'pushed' the metal out a bit, the firebox was quite heavily annealed and maybe that was enough to squish it out as well as cut. It's also quite thick metal.

 

I've folded up the cab floor and got a reasonable fit:

 

but I'm stumped as to what exactly I'm supposed to do with the splasher tops.  The instructions say:"Fold up the cab floor, including the splasher sides. Fit their tops and trim them flush to the front edge of the floor." But the splasher tops seem huge compared to the gaps they need to cover and I'm worried I'm missing something obvious here...

 

Plus the cab floor part of the splasher sides are curved so I think I'll need to curve the splasher tops to fit them. The length is about right to come nearly flush to the cab front and extend under it in a curve that would cover the wheel in an arch that would butt between the cab front and the cab baseplate (below the level of the cab floor).  Looking at Dikitriki's post (#76) it does look like they are just waaay bigger than they need to be.  There is also a half etched line along one long edge which is the mating face I suppose.

 

Finally, a brief look at the wood rather than the trees:

I'm a little bothered about a small gap between the boiler and the firebox. I had thought a boiler band went over that join, but the instructions say not so I may need to resort to body filler.  I've also got to tackle the firebox leading edge curve and I don't have much to go on other than photos. Anyone know any reference dimensions or radii that I could trace onto pieces of paper to use as reference curves?

Edited March 31, 2016 by Tim2014

[Dave Holt]

Tim,

There is a boiler band just in front of the boiler/firebox cladding joint. There,s about a 1" gap between the edge of the firebox front and the rear edge of the band, so you will need to fill any gap in the model before fitting the band. The front corners of the firebox have a 4.5" radius.

Hope that helps.

Dave.

[Horsetan]

....I tinned each beading and sweated it onto the footplate, I haven't been using that technique as much as I should, I'm amazed at how little solder you actually need to make the joint.

I am much in favour of the "use as little solder as you can get away with" method. It does tend to save on the cleaning-up afterwards!

[jazz]

"The easy way is to use a drill bit at least twice the size hole, with light pressure ..."

 

I agree but, for anything above about 4mm in diameter, I use one of these; there is much less danger of 'digging in':

 

David

 

Hi David.  Been admiring Tims scot and noticed this tool you use. Could you tell me where you got it, I think that will be perfect instead of using a drill bit in the fingers.  Thanks, Ken

[Dave Holt]

Tim,

A possible reason why the rear sections of splasher seem way too long is that on the real thing they extend through the (wood) cab floor to meet with the drop section of footplate at the bottom of the cab side sheets. Perhaps the kit designer has replicated this?

Dave.

[philbax]

We just use a little less solder!

 

and a bigger magnifying glass!!

[Horsetan]

and a bigger magnifying glass!!

I haven't yet needed one, and I hope what remains of my eyesight will hold out a little longer!!!

 

I still can't get my head round the 2FS lads who can do their builds without magnifiers.

[N15class]

It is looking good. I have a Jubilee to do so it is all extra interesting for me. I have not built many LMS locos.

[Guest Isambarduk]

Hi David.  Been admiring Tims scot and noticed this tool you use. Could you tell me where you got it, I think that will be perfect instead of using a drill bit in the fingers.  Thanks, Ken

 

Well, Ken, it's been a while now but I would say that I picked it up from Chronos (www.chronos.ltd.uk) but I cannot find them listed there now.  No matter, they are available from Axminster (www.axminster.co.uk/axminster-hand-countersink-952356) or here is something very similar, and rather cheaper, that would probably be just as suitable for our purposes: www.amazon.co.uk/gp/product/B00BZH4CDI

 

Actually, rather than run my fingers on drill bits, I have a set of four worn (ie not so likely to dig in) imperial drill bits that I mounted in wooden handles (home made, of course!) to twiddle in smaller holes that need deburring.  Very handy, I find.

 

David

[Tim2014]

Tim,

A possible reason why the rear sections of splasher seem way too long is that on the real thing they extend through the (wood) cab floor to meet with the drop section of footplate at the bottom of the cab side sheets. Perhaps the kit designer has replicated this?

Dave.

Based on that fact I think that's definitely what was intended so I'll see how it pans out. I really appreciate your earlier post with the dimensions for the boiler band spacing and the firebox curve too. A great help (again!)

Tim,

A possible reason why the rear sections of splasher seem way too long is that on the real thing they extend through the (wood) cab floor to meet with the drop section of footplate at the bottom of the cab side sheets. Perhaps the kit designer has replicated this?

Dave.

Based on that fact I think that's definitely what was intended so I'll see how it pans out. I really appreciate your earlier post with the dimensions for the boiler band spacing and the firebox curve too. A great help (again!)

[Funtleyworks]

Thanks for the humour, much needed I feel!

 

I tried the 'double sized drill' method on the single washout holes (as recommended by Peter Cross) and it worked well, no ridge and a barely visible chamfer. I had tried a countersink bit a bit like Isambarduk recommended, it was probably a bit oversize for the washout holes though.  I think the cutting broaches may have 'pushed' the metal out a bit, the firebox was quite heavily annealed and maybe that was enough to squish it out as well as cut. It's also quite thick metal.

 

I've folded up the cab floor and got a reasonable fit:

SANY3381.JPG

 

but I'm stumped as to what exactly I'm supposed to do with the splasher tops.  The instructions say:"Fold up the cab floor, including the splasher sides. Fit their tops and trim them flush to the front edge of the floor." But the splasher tops seem huge compared to the gaps they need to cover and I'm worried I'm missing something obvious here...

SANY3386.JPG

 

Plus the cab floor part of the splasher sides are curved so I think I'll need to curve the splasher tops to fit them. The length is about right to come nearly flush to the cab front and extend under it in a curve that would cover the wheel in an arch that would butt between the cab front and the cab baseplate (below the level of the cab floor).  Looking at Dikitriki's post (#76) it does look like they are just waaay bigger than they need to be.  There is also a half etched line along one long edge which is the mating face I suppose.

 

Finally, a brief look at the wood rather than the trees:

SANY3380.JPG

I'm a little bothered about a small gap between the boiler and the firebox. I had thought a boiler band went over that join, but the instructions say not so I may need to resort to body filler.  I've also got to tackle the firebox leading edge curve and I don't have much to go on other than photos. Anyone know any reference dimensions or radii that I could trace onto pieces of paper to use as reference curves?

 

Thanks for the humour, much needed I feel!

 

I tried the 'double sized drill' method on the single washout holes (as recommended by Peter Cross) and it worked well, no ridge and a barely visible chamfer. I had tried a countersink bit a bit like Isambarduk recommended, it was probably a bit oversize for the washout holes though.  I think the cutting broaches may have 'pushed' the metal out a bit, the firebox was quite heavily annealed and maybe that was enough to squish it out as well as cut. It's also quite thick metal.

 

I've folded up the cab floor and got a reasonable fit:

SANY3381.JPG

 

but I'm stumped as to what exactly I'm supposed to do with the splasher tops.  The instructions say:"Fold up the cab floor, including the splasher sides. Fit their tops and trim them flush to the front edge of the floor." But the splasher tops seem huge compared to the gaps they need to cover and I'm worried I'm missing something obvious here...

SANY3386.JPG

 

Plus the cab floor part of the splasher sides are curved so I think I'll need to curve the splasher tops to fit them. The length is about right to come nearly flush to the cab front and extend under it in a curve that would cover the wheel in an arch that would butt between the cab front and the cab baseplate (below the level of the cab floor).  Looking at Dikitriki's post (#76) it does look like they are just waaay bigger than they need to be.  There is also a half etched line along one long edge which is the mating face I suppose.

 

Finally, a brief look at the wood rather than the trees:

SANY3380.JPG

I'm a little bothered about a small gap between the boiler and the firebox. I had thought a boiler band went over that join, but the instructions say not so I may need to resort to body filler.  I've also got to tackle the firebox leading edge curve and I don't have much to go on other than photos. Anyone know any reference dimensions or radii that I could trace onto pieces of paper to use as reference curves?

 

Thanks for the humour, much needed I feel!

 

I tried the 'double sized drill' method on the single washout holes (as recommended by Peter Cross) and it worked well, no ridge and a barely visible chamfer. I had tried a countersink bit a bit like Isambarduk recommended, it was probably a bit oversize for the washout holes though.  I think the cutting broaches may have 'pushed' the metal out a bit, the firebox was quite heavily annealed and maybe that was enough to squish it out as well as cut. It's also quite thick metal.

 

I've folded up the cab floor and got a reasonable fit:

SANY3381.JPG

 

but I'm stumped as to what exactly I'm supposed to do with the splasher tops.  The instructions say:"Fold up the cab floor, including the splasher sides. Fit their tops and trim them flush to the front edge of the floor." But the splasher tops seem huge compared to the gaps they need to cover and I'm worried I'm missing something obvious here...

SANY3386.JPG

 

Plus the cab floor part of the splasher sides are curved so I think I'll need to curve the splasher tops to fit them. The length is about right to come nearly flush to the cab front and extend under it in a curve that would cover the wheel in an arch that would butt between the cab front and the cab baseplate (below the level of the cab floor).  Looking at Dikitriki's post (#76) it does look like they are just waaay bigger than they need to be.  There is also a half etched line along one long edge which is the mating face I suppose.

 

Finally, a brief look at the wood rather than the trees:

SANY3380.JPG

I'm a little bothered about a small gap between the boiler and the firebox. I had thought a boiler band went over that join, but the instructions say not so I may need to resort to body filler.  I've also got to tackle the firebox leading edge curve and I don't have much to go on other than photos. Anyone know any reference dimensions or radii that I could trace onto pieces of paper to use as reference curves?

 

First rule of kit building. Don't always believe the instructions! Definitely a boiler band between boiler and firebox. And as for the radius of firebox then I always go by eye!! 

[jazz]

Well, Ken, it's been a while now but I would say that I picked it up from Chronos (www.chronos.ltd.uk) but I cannot find them listed there now.  No matter, they are available from Axminster (www.axminster.co.uk/axminster-hand-countersink-952356) or here is something very similar, and rather cheaper, that would probably be just as suitable for our purposes: www.amazon.co.uk/gp/product/B00BZH4CDI

 

Actually, rather than run my fingers on drill bits, I have a set of four worn (ie not so likely to dig in) imperial drill bits that I mounted in wooden handles (home made, of course!) to twiddle in smaller holes that need deburring.  Very handy, I find.

 

David

 

Thanks David. I will order the one from Amazon. Ken

[Tim2014]

I have been burning my fingers and using lots of solder, armchair critics, stanier experts, your kind attention please! I have taken the plunge and shaped the front of the firebox.

 

The main profile is based on Dave’s recommendation of 4.5” which I tried to replicate by creating a gauge based on a ¼ arc of a 5mm diameter hole in some scrap etch.  I then faired in by eye.  I have to say I can’t find any photographic evidence for a gap between most of the firebox and the rearmost boiler band, but had a close look at the scale drawings and I think perhaps representations of the top profile of the firebox may be responsible for the appearance of a gap – the outer edges of the firebox being faired back behind the line of the boiler to firebox join? 

 

I can’t find a really good photo of the top of the firebox/boiler transition anywhere, but Richard’s SVR video from the footbridge was sufficient to show that in its current state, Royal Scot seems to fair seamlessly on the top from firebox to boiler (with no evidence of a firebox cladding clamp either, although a few photographs hint they were there in Mainline days).  Be that as it may, it’s the ‘it looks right’ that I’m trying to capture, so let’s let the photos do the talking, complete with firebox beading and one side’s lower cab beading:

 

Incidentally, I think there is a dimensional error in the instructions for the firebox bands.  The structions say 33mm from cab front to mid firebox bands, 35mm between firebox bands. From the drawings I calculated 32.1mm and 32.9 mm for those dimensions, and I’m pretty close to those on the model. The drawings suggest 3.6mm from the firebox front to the front firebox band and I used that to locate the front band (on the basis that the smaller dimension will look 'out' the most if I get it wrong).  Had I used the dimensions in the instructions, the front band would be only 1.6 mm from the front of the firebox and that is obviously wrong.

[Tim2014]

I was contemplating spraying the now rather nicely modular firebox in ‘photographic grey’ etch primer to aid comparison to prototype pics, but not sure what the consequences of that might be on future soldering operations? Presumably the whole point of etch primer is that it’s quite hard to remove…but I imagine a fibreglass brush and wet and dry would sort it out.

[Tim2014]

On the subject of painting, the cab interior is beginning to loom large in my not-too-distant plans.  I think I can make the cab backhead removeable quite easily, but the rest (including glazing!) is going to rapidly get much harder to paint as assembly progresses.  What do you good folks do in that regard? At the moment I’m thinking I’ll use thin clear plastic for glazing and PVA to hold it and any window frames in place.  I should be able to get a paintbrush or airbrush into most areas as long as the backhead can be taken out.

 

The cab floor is folded up and fits nicely:

 

I tried to extend the splashers to the cab floor, but they come rather close to the wheels so in the interest of avoiding sparks, I decided to chop them off  below the cab floor:

 

I can also confidently recommend that you do not solder the cab floor down without getting the cab backhead fit sorted. It’s a lot easier to check the quite complex shape when you can still remove the cab floor and splashers.  I needed to remove about 1 mm from the bottom of the casting to get the right height, and took that opportunity to remove a slight moulding line around the edge.