7mm Gladiator Royal Scot build

[Dave Holt]

Dave,

You mention relief valves being painted green, but Tim was referring to safety valves. The relief valves are attached to the cylinders not the boiler or firebox. Can you clarify please?

 

Surely the safety valves would be bare metal, which as you say would rapidly discolour to black, due to the high temperature.

Cheers,

Peter

Yes, sorry for any confusion. I was referring to the boiler pressure relief valves being green. The cylinder relief valves were probably bare metal although I'm not absolutely certain. If not, black. These latter don't get as hot as the boiler and tend to tarnish but retain the gunmetal look.

Dave.

[Tim2014]

Have any of you crafty types got any tips on how to remove a small stub of 0.4mm drill bit that has broken off just below the surface lip of a 0.4mm hole in a bronze casting?  I'm thinking I may have to take some modellers license with which ports on this lubricator had piping attached! Or write off the casting

And it was going so well...!

[Marshall5]

Somewhere in the back of the grey matter I seem to remember reading that a solution of alum will dissolve the steel but leave the bronze.  Sorry I can't be more exact but I'm sure there'll be something on the interweb.  Spark erosion is used in industry I believe.

Ray.

[3 link]

Hi Tim,

 

Being an 0.4mm bit I think it's probably best to kindly ask the supplier for another casting. Were you using a pillar drill? also when using small bits I personally use a light machine oil as the slightest snatch and they will break.

 

Martyn.

[Tim2014]

Somewhere in the back of the grey matter I seem to remember reading that a solution of alum will dissolve the steel but leave the bronze.  Sorry I can't be more exact but I'm sure there'll be something on the interweb.  Spark erosion is used in industry I believe.

Ray.

Beauty Ray - I'm formerly a chemist so really should have considered the chemical route. Have nothing to lose by trying it (given that hooking up the wrong ports would annoy me every time I looked at it!), so I will give it a go and report back.  Failing that, I'll get another casting.

 

No, I have no pillar drill, the hi-tech equipment consisted of using the left thumb and forefinger to hold the casting, the right hand holding an electric screwdriver fitted with mini drill chuck and a 0.3 or 0.4mm drill (in the vertical, like a pillar drill).  I stick my head close to the whole thing so it's all in focus, with my chin on the same level as the casting and have the drill hand wedged against my forehead.  Everything locks together and with my extreme myopia, all the important bits are in macro focus.  The eye is well away from the drill bit and as you know, there is no force involved to have anything slip out of control.  I then enter a Zen-like state, breathing evenly and carefully engage the drill in the dimple of the casing with the barest of weight on it.  I start the screwdriver (which spins at probably 120 rpm) and gently pulse the pressure on the drill (more accurately allow more of the screwdriver weight to rest on the bit, it has to be supported at all times).  I know I am winning as the metal dust begins to gather around the hole.  Hand-powered drills, pin vices etc simply can't get the rotation speed I think you would need and suffer from alignment issues.  The screwdriver doesn't turn fast enough to overheat.  I did wonder about using cutting oil to help, but I think oil just lubricates things a bit and is mainly to transfer heat.  With this job, the heat generated vs the heat capacity of the casting didn't warrant it (it happily soaks up several seconds of heat from an 80W iron set at 290C with 145 solder and I can't hold that for long enough with bare fingers, while drilling, the casting didn't get warmer than skin hot).

 

I broke 4 bits before trying this method without drilling one adequate hole.  I lost 3 drilling the 9 holes I did, one dropping the drill (!), one slipping during the initial alignment, and the one which snapped off, actually as I was trying to remove the bit too hastily.  Afterwards, I found gently lifting the screwdriver and bit and allowing the weight of the casting to gradually enlarge the hole enough to drop off the weight under it's own steam.  I was rushing, flushed with success, having drilled a bit deeper than previously when I broke it off.

 

Hardly enough experience to warrant being a manual, but I'm pretty confident I'd be able to do a typical loco on one or two drill bits with that method. I like the fact that I am completely in tune with the whole process, I can hear and feel when the drill is cutting and see clearly both the alignment and the metal dust accumulating.  I can't see that I could do that even with a good quality drill setup as I lack space, and my rapidly aging vision struggles at those sizes at 'normal' viewing distance.

 

I'd be curious to know what others do though...

[Tim2014]

While waiting for the pharmacist to get my alum crystals in, I decided to make a start on the cab backplate.

Thank goodness for Duncan's cab photos back on page 11! They are proving an absolute godsend as I can't find a single decent photo of a rebuilt Scot backhead in service.

It doesn't help that the steam manifold supplied with the kit is probably fairly generic, and although I made some attempts to tart it up, I probably should have ditched it and scratched my own. The two downports are too close to the water glasses and the regulator gland.  I'm having trouble figuring out how the brass gauge backheads sit in relation to the cab windows and backplate.  These pics show progress so far and the fireman's side which has already been raised a bit (and not cleaned up). I'm really not sure about the angles of the plates (hard to tell from photos), I had thought they were in the same plane as the backhead, but the fireman's side must be angled, or no-one would ever be able to see out of the front cab window! The instructions seem to indicate an angle too, but not I think as extreme as I've had to resort to.

 

I'm hoping the sand gun had disappeared by 1959!

[Sandy Harper]

Hi Tim

Are these any use to you?

Sandy

 

[ozzyo]

Hello Sandy,

 

the photo above is smashing, what was the smokebox number plate on the loco with 46101 on the cab side?  Then what was the number on the cab sides of the loco that has 46101 on the smokebox door number plate?

 

Interesting!!!!!!!!

 

OzzyO.

[Sandy Harper]

Hello Sandy,

 

the photo above is smashing, what was the smokebox number plate on the loco with 46101 on the cab side?  Then what was the number on the cab sides of the loco that has 46101 on the smokebox door number plate?

 

Interesting!!!!!!!!

 

OzzyO.

I reckon the door has been 'robbed' from the one in front and will have the number plate refitted later OR maybe the cab side sheets have been swapped????

 

Nice to see your still on here mate!

Best regards

Sandy

[Tim2014]

Hi Tim

Are these any use to you?

Sandy

Hmm, the site saved my ratings, but not my follow up post! Let's try again.

 

Thanks so much Sandy, those pics are great.  The first is a much better quality of one I have been struggling to make use of, the second one I'd never seen before, and as well as being a curiosity as Ozzy has pointed out, very useful for my purposes.  Do you have any other info about them? Presumably it's the end for 46101 and it is donating useful parts.  I don't think that control handle on the LHS at mid backhead level is a permanent fixture - do you think it was bolted on to avoid losing it - possibly from the valve above the steam brake assembly (carried on a bracket on the RHS and visible in the top pic?). Edit: looking at the full size pic on a PC, I think it's just the camera angle and the valve is actually still on the bracket in it's proper location.

 

Back to the model, I spent an evening with the calipers poring over the apparent scale drawing on the back of Loco Profile No1.  Everything seemed pretty scale except the manifold casting itself.  Waaay to long, on both sides, but the LHS is not as critical regarding placement of other piping.  I checked my DA Jubilee and that has exactly the same casting, so I guess this is one area where a bit of initiative is called for on the part of the builder.  I think I can just cut a section out, which would have been a lot easier before I started bodging - we shall see!

 

A quick shout out for Hobbyhorse Developments who have ceased trading (hopefully pending a new owner), I was looking at the exhaust steam injector I purchased from them for the Scot and admiring the superb quality when I realised that there was an equally superb schematic with it that described what the various parts did, their names, the pumbing routes and a table giving piping diameters!  Armed with that data I was able to go to photos and work out what likely cab backplate piping diameters were.

I came up with:2", 1 3/4" (or 1.5"), 1", 3/4" and 3/8" used on the full size cab backplate plumbing.  I make 3/8" around 0.22 mm in 7mm which is hardly visible.   I may use slightly larger if it looks better with everything else. I do hope someone buys them up as I a can see myself using them regularly.

 

I have the lubricator casting stewing in some alum as I type...lets hope it's from double disaster to triumph.

Edited August 4, 2017 by Tim2014

[Tim2014]

Somewhere in the back of the grey matter I seem to remember reading that a solution of alum will dissolve the steel but leave the bronze.  Sorry I can't be more exact but I'm sure there'll be something on the interweb.  Spark erosion is used in industry I believe.

Ray.

Kudos to you Ray.  The Alum worked slowly, but it worked.  Had I not tried to solder *over* the broken drill and asked advice first I think it would have been much, much quicker.  Anyway, here is the end result (the 'blocked' port with the drill bit in was the 2nd in from the left of the pic):

A bit of discolouration, but I suspect that is just surface oxidation.  The tinned copper wires are unaffected, as is any solder and the casting (when I say the solder is unaffected, it is discoloured and it's melting point might be different, but it doesn't dissolve, nor does oxidation seem to penetrate far below the surface).  I had boiled it for about 4 hours last night and left it in the solution cooling overnight, but there still seemed to be a lot of drill bit in there this morning so I was a little dubious.  I 'wasted' a drill bit drilling into the hole in order to make absolutely sure some drill bit metal was exposed to the solution, and placed a test broken drill shank into the solution along with the casting for another boiling session this morning, again, it's the second port in from the LHS, in this case, still blocked:

The old shank immediately started an effervescent fizz in the solution, and it occurred to me this process might prevent fresh solution reaching the stub in the casting, so I placed an ultrasonic cleaner head (from a DIY electronics kit) on top of it, and oriented the casting so that any bubbles would float up and out of the hole.  I have no idea how critical any of these were to success, I suspect contact with hot alum solution is actually all that is required, the ultrasonic cleaner does nothing to remove grease from car-parts (which is what I hoped it would do), so I don't think it's especially powerful, but it may have been enough to agitate bubbles out of the casting, although I could only be bothered to leave it in place for 10 minutes or so of the ~4 hours of soaking today.  The drill shank? Completely gone after 2 hours in hot alum solution! Not a trace left, I honestly couldn't believe it, but it's absolutely true.

 

If for some reason anyone does want to try and replicate this, I used a glass container to make a very concentrated alum solution in (use hot water).  This sits in a saucepan with shallow water in it which is heated.  So the Alum never gets above 100C, but that also means no alum comes into contact with kitchen ferrous metal.  You need to make sure neither container boils dry, I had a lid on it and checked it regularly, and don't leave a casting in the solution to cool because the Alum will very effectively encase it and you'll have to dissolve it off.  Easy to do if you reheat of course. These pics were taken this morning when the hot solution from last night had cooled and I had broken the alum crystal crust up and added some fresh warm water to begin it dissolving again.

When I say Alum, it was potassium aluminium sulphate.  You can get ammonium aluminium sulphate which is also called 'alum' but I don't know if that works for this.

 

I take no responsibility for any damage you do to you train, kitchen, pans or health, but I will say that compared to molten lead and solder smoke, potassium aluminium sulphate is pretty innocuous.  After what I have seen I can confidently say DO NOT TRY THIS WITH CAST IRON COOKWARE!!

[Tim2014]

While the alum was doing it's thing last night, I got back to the backplate and steam manifold. Back on track now I think.  The steam brake is in the hole provided for it, but I think it's a bit too close to the center so will measure that and may move it.

[Tim2014]

This is still work in progress. I am probably going overboard, but I'm enjoying it which is what really matters hey?

 

 

[Tim2014]

I think I'm over the hump now, but will try and knock up firehole doors and a drivers heatshield. Please say if any controls are in impossible positions. I'm aiming for slow forward since thats the only position a viewer is likely to have time to notice!

Edited September 21, 2017 by Tim2014

[Marshall5]

Regulator looks to be closed or nearly so and vacuum brake is off.  A good looking backhead.

Ray.

[Tim2014]

I have finished the cab backhead build.  Here it is in black (!) etch primer. It's a pleasing satin when not illuminated with a flash, which shows every file mark in the metal:

 

It's at least 70 individual bits, and in the end, quite a few components are scratch built. If I were to do it again, I would definitely check dimensions much more carefully and would likely not use the supplied white metal manifold which appears to be more suitable for a Jubilee or Black five.  I have no idea how many hours it has taken, but it's a lot, and at one point today I was worried I may have wasted all of it because I made a stupid error deciding to persist with my first batch of etch primer.  I had already got a clue it wasn't quite right when wisps of thread appeared to stream off the plastic diesel shunter body I was using as a test piece (still planning on testing my BR green and lining!).  But instead of calmly taking stock, I jumped to the conclusion it was the fairly aggressive thinner I'd used that must have had some kind of reaction with the plastic.  But no, it was 'cobwebbing', which I now know is caused by paint that is too thick or temperatures that are too high or the wrong thinner. Possibly all in my case.  I immersed it in a solvent bath and sourced some solvent that I knew was compatible with acrylic and epoxy paint.  A few paint reservoirs of solvent blasted on with the airbrush took it back to bare metal and the next paint coats, suitably thinned down this time, went on fine.

 

I notice in this 'larger than life' view, that there is still a bit of webbing.  Whether that was from these paint coats or the original, I do not know.  But it's not going to be visible hidden in the loco cab with loco crew in front of it.  I hope.

 

Now to get the enamels and brushes out.  I'm in familiar territory there so it shouldn't be too much trouble.  And for construction, it's back to the footplate lubrication pipework.

 

3 years since I got the kit now! Not exactly scintillating progress is it?! 

[Tim2014]

Merry Christmas to you all!

 

Precious little to report sadly, but I have finally spent a couple of hours working on a Laurie Griffin Silvertown lubricator (I started it because I couldn't find my 'alum special', but have now got that!).  I recall reading the instructions when I received them many months ago and being a little sceptical of getting microtubing through both sides of the casting, but I need not have worried, the casting is of very high quality and the holes line up very well, so it took very little time to drill though each moulding 'pip' and end up with a casting that is ready to take the wire oil lines.  Given the hassle with drilling out my other one, and the difficulty of soldering so many small pipes into whitemetal, I will be making use of Lauries castings for these parts I think. THey aren't cheap, but nor are 0.3mm drills, and my sanity is worth something - to me anyway!

I hope you all have a lovely festive season and look I forward to posting more progress (dare I risk saying finishing the model?!) in 2018.

[Tim2014]

A request to any 7mm accessory manufacturers: Please, please, please can you cast one of these as I really don't want to make another one (snipped from one of Dikitriki's pics from the Severn Valley Gala):

 

Just 6 wires to go in and some cleaning up and then I have to start the spaghetti.  I think it will be soldered onto the footplate next though.  Hopefully it doesn't all fall apart.

 

The main body was two cannibalised 19-016 LMS/BR Oil atomisers from Laurie Griffin (which are 4 ports), the rest is a lot of faffing with tube, wire 12BA bolts and 2 grades of solder.  And a lot of swearing.

 

Now if anyone has a picture of one of these in service on a Scot in the late 1950s and it doesn't look like this...keep quiet!

[JeffP]

If you make one and send it to Laurie, I'm sure he'll add it to his range.

[Horsetan]

If you make one and send it to Laurie, I'm sure he'll add it to his range.

He has already made one....oh wait, hang on...

[Tim2014]

Yes - I've made one and *nothing* will persuade me to give it up! Nor do I think it's worth anything to anyone else tbh. What would be useful though is a generic 12, or 10, or 8 (whatever a maximum was), port 3-way tubular manifold that can be cut down to whatever number of ports is required - that could be used on a variety of locos, as opposed to just Scots.  I know I'm inexperienced but I reckon it's far easier to cut down a casting than it is to bodge two together.

 

I can't say that really any of this was enjoyable. But sitting back looking at it finished makes me very happy indeed. I can't imagine the loco without it.  In a few days I may pluck up the courage to tidy up the top ports which do let it down a little.

 

Happy New Year all

[PAD]

Hi Tim,

Great work! 

 

It really  makes  a big difference adding all that extra detail, but  it's such a  pain making those fiddly little bits by hand from scratch. I got  lucky with my Black 5 as I was able  to source the  atomiser from Griffin (or  maybe Hobbyhorse, sadly no longer  with us). I still had to make  the isolation tap behind it  from scratch, which needed 8 separate parts, so god knows how  many were needed for  your atomiser!

 

Speaking of  extra detail, you  could add some short lengths of wire to the  slots in the  hinges on the inspection plate to represent the hinge bolts. I did that on my  Duchess after seeing  them on Dikitriki's Finney build on Western Thunder.

 

Cheers,

Peter

 

[Tim2014]

Thanks for those kind words and the idea of the hinges Peter - I was surprised the one access plate is so prominently etched while the other is missed off completely, a representation of hinges will be a good way of doing them both. I had to dismiss the small oil box, there simply isn't enough room.  The wires are significantly oversize to be scale, and that really takes up space on the footplate.  I must head over to WT to check out that Duchess - one of those is definitely on the bucket list!

 

The atomiser is only 14 parts in the end, two of which are the castings - plus the 14 wires though. My 'tap' was a real cheat: two crossed tubes with the top of a pin soldered in! Definitely at the limits of all my abilities so I'm very glad it's only on the one side. I significantly underestimated how hard it would be to weave and hook up all the spaghetti too.

 

All this has made the prospect of fixing my 'alum special' 6-port lubricator on the other side seem really simple (famous last words), but I'm really tempted to jump into the smoke deflectors first because they will transform the look of the loco.

[Tim2014]

Yikes, time flies and progress is slooooow. Coming up for four years on this...I hope your modelling is progressing at a more rapid pace.

 

I have got the RH lubricator onto the footplate and then turned my attention to this:

1. I don't know what it's actually called (another lubricator, or oil box or...?).

2. It looks like preserved locos - or at least Scot's Guardsman - have a different variant.  All the 50/60s pics I can make it out seem to have the form shown - which I realised AFTER bodging the supplied casting.  I think I'll file this one down on the top and bottom to look a bit more like the pic, but curious if anyone can shine a bit of light into what it is and whether they would all be like the above pic?

[Tim2014]

I decided to grind and file the piece down a bit.

Then seized with sudden enthusiasm and a long weekend, I decided to cut out and shape the smoke deflectors.  I've been worried about these because they are such a distinctive part of the loco, but so far so good I think.

 

There are two sets supplied in the kit, one in thin metal and one in thicker.  The originals were apparently from 1/8" sheet and even the thinner metal is oversized for that so I went for the thin ones, which annealed and bent up nicely.  Loco Profile No1 has some great scale dimensions which made it easy to find some suitable PVC pipe for checking the rolled diameters against.  I rolled too small, then press round the final former to open them up.  When held in place by hand, they look to have the curves in the right places and I think I will solder them to the footplate and figure out a way to lock them in place using the handrails, which are part of the mounting on the prototype.

 

I couldn't resist a quick pose outdoors