7mm Gladiator Royal Scot build

[Tim2014]

Well, that's not the answer I was hoping for, what a conservative bunch

I may yet fit the rivet, I had a go at enlarging a hole sufficiently large to take a rivet (opening it out about 1mm in diameter).  I was using one half of the 'original' Scot coupling rod and so far as I can tell by eye, when matched up with the other half, the larger hole is exactly concentric with the other, undrilled, half of the coupling rod, so hopefully I will be able to enlarge the holes on both coupling rods using my existing tools to take the stock rivets without altering the crank spacing enough to cause issues with the chassis, that was my main fear.

But I still think this looks better than the stock rivet (if the pin head is filed down a bit, I could even put a hex on it)! I will keep laminating bosses and fiddling with the fluting while I make up my mind (I will not ignore your recommendations lightly though, I promise).

 

I've done my head in flicking from one page of instructions with a diagram to the page with the build instructions and then the contents list page too! So much so I realised all I needed to do was make a copy of the diagrams and contents page on single sided paper, but I keep forgetting!

 

I went with an order from Ragstone in the end and took the opportunity to also source the AWS parts which aren't included in the kit.

 

The front bogie is loosely assembled so I can get a feel for how to spring/compensate it and also how much movement is required to get round my curves.  For the first I'll probably hack up some of my Meteor hornblocks, for the second, surprisingly little, but not having it all rigid does mean it keeps fouling the front wheels, it'll be tight in that area, no wonder the kit recommends taking the sanding gear inside the brake gear!

 

And finally, I've checked the continuity between the leading tyre and the brake bracket and all is good, no short. Better get back to burning the fingers.

Edited May 14, 2015 by Tim2014

[Grasshopper John]

Hello Tim, one thing I've got used to assembling my valve gear is the use of 10, 12 and 14ba nuts and bolts, I use CH bolts and once fitted I file away the groove in the head to give it a rivet effect, you also have to file the nut away for clearance but the effect is quite good.

 

Grasshopper.

[Tim2014]

Hello Tim, one thing I've got used to assembling my valve gear is the use of 10, 12 and 14ba nuts and bolts, I use CH bolts and once fitted I file away the groove in the head to give it a rivet effect, you also have to file the nut away for clearance but the effect is quite good.

 

Grasshopper.

Thanks John, That's a very good idea - I've got a selection of those (courtesy of 'BA Bolts' whose service was superb BTW) and figured they may come in handy with the valve gear.  I bought my first pack of cigarette papers yesterday after reading your tribulations with soldering valve gear bits to each other.

[Tim2014]

Cylinders are now 'wrapped', that was a pig of a job, but made much easier by spending a lot of time getting the fit spot on before reaching for the iron.  In hindsight I would spend even more time getting it perfect, because you can't improve it once you start tacking it together.  A much longer, but weirdly therapeutic job was getting one side's slides all cleaned up and silky smooth. I found it very satisfying going from a lump of a casting to something resembling fine machinery.  Now I've just got to start getting it all assembled.

Don't use AA batteries for formers, they're too big (how do I know that?). AAA would be closer, but wooden dowel is probably easier to use.

 

Test fit to chassis, I spent a lot more time closing up the worst of these gaps after I took this:

 

The little 'waisted' bits are presumably to allow crisp folds because the wrappers are quite a bit wider than the front and back faces and everything seems to catch when you try and fold it up making it very difficult to get the curves right and everything square.  If I were to do it again, I'd cut the front and rear faces along the fold lines and use them as templates for the folds in the sides.  I also desoldered the faces and redid them after realising I'd built in a taper outwards, wider at the bottom after my first attempt using the wrapper to align them.  Checking with calipers and a straight edge or equivalent is the way to go.

 

Still, it went together OK in the end I think:

 

The castings really are quite a mess as they come in the kit.  Still, that's presumably why the kit is cheaper than some others, personally I'd rather spend the time than the money!  A set of calipers was really useful for checking where the misalignment in the slides and crosshead was causing a few sticky patches.

 

[N15class]

The use of a felt tip pen on the slide bars etc also show the tight spots as it wears off when sliding up and down.

 

Looks good so far I fancy doing one of these locos.

[Tim2014]

Blimey, valve gear is hard work!

[dikitriki]

Blimey, valve gear is hard work!

 

 

Can I suggest an order.......and make sure every component/join is free and has sufficient movement before you move onto the next part?

 

* Coupling rods

* Connecting rods and crosshead (watch for front crank pin nut clouting the back of the crosshead)

* Expansion link, eccentric rod and return crank

* Radius rod, combination lever, union link and crosshead drop link.

 

If you can, I would suggest powered track test before each stage is signed off. You will also need to make it all removable for the different stages.

 

Others will, of course, have a different preferred order of construction.

 

Pages 11(bottom) to 18 deal with the build of a Gladiator Patriot's valve gear which will be pretty much the same http://www.westernthunder.co.uk/index.php?threads/dikitrikis-dark-side-l-y-crab-temporarily.100/page-11

 

I ignore my own advice of course, but then I can't remember when I last built a loco without valve gear!

 

Looking Good.

 

Richard

Edited May 19, 2015 by dikitriki

[Tim2014]

Can I suggest an order.......and make sure every component/join is free and has sufficient movement before you move onto the next part?

 

..

I ignore my own advice of course, but then I can't remember when I last built a loco without valve gear!

 

Looking Good.

 

Richard

Absolutely, I will be following to the letter

Thanks Richard, sounds like good advice, and slightly different order from the instructions I believe.  I did the slidebars before the valve guides because they are a lot closer to the wrapper edge and I had to to use 145 for both (in hindsight, 185 would have been a good idea on the wrapper!) and I thought if the edges were going to delaminate, they'd do it on the slidebars and then it's less work if I have to start again.  I used a huge adjustable spanner very gently done up as a heatsink around the cylinders, though it's main role was to hold the cylinders in place while I got the iron in onto the slide bar casting.  Tacked into place to check square (on a section that's hidden), then went round the seams veeery carefully watching the silvering as the solder flows and wicks along the edge of the casting.  I did contemplate using my rubbish flame, but chickened out.  I'll do the other slidebar, the valve guides and then get the connecting rods on and do a full powered check.  I'm reasonably confident up to that point.  Beyond that, I couldn't tell a radius rod from an expansion link - but cutting them off the etch, filing and looking at prototype pics helps that all sink in.  I'll be full bottle on Walschaerts valve gear by the end of this build.

 

Stephenson's can (for now) remain a mystery although I found I have a lovely atmospheric pic of it from 2002 if anyone is interested?

 

The valve guides will be a post in their own right, thank goodness for Jeff P's post about a brass rod insert, I'm planning to use that on them as the centering was terrible.

[Grasshopper John]

Hello Tim,

Be prepared to assemble - disassemble many times on the valve gear, even when you think it's right something will bite your backside

 

Hope this helps OzzyO gave me this buts it's Dikitriki aka Richard Picture from his superb build.

 

 

This should help you identify the parts a bit easier.

[Tim2014]

Thanks John, That annotated pic is very helpful and I had a real laugh when I read your post: I got the other slidebar assembly on last night.  I swore it was OK when I ran the iron round the seams, but then when I popped it on the chassis it looked like it was just a tad low.  I convinced myself it was probably OK and went to bed.  The following morning my 8 year old son asked why that side pointed to the front driving wheel center not the middle wheel center.  He knew where they should point after I'd passed my (3 day old!) wisdom onto him after attaching the first one.  So that second side is the first (of no doubt many) undo operations!

[Tim2014]

The instructions talk about using the motion support bracket to help align everything. Does this mean I could 'cheat' on the slidebar/cylinder join (see post above) and use the assembled motion bracket to help align the cylinder/slide bar assembly? I think the slight inclination of the cylinders required would be unnoticeable (one side very slightly low, the other very slightly high), and the slidebars are held at the non-cylinder ends by the motion bracket so they *have* to line up at that end.  So I'm thinking of assembling the motion bracket next, before trying to relocate the slidebar to give an idea of how far off everything might be and possibly save some angst.

This side I'm happy with:

 

This side I think needs raising a tad:

Apologies for the photos, it's hard to show with a macro setting, dodgy lighting and no tripod!

[Tim2014]

...

Pages 11(bottom) to 18 deal with the build of a Gladiator Patriot's valve gear which will be pretty much the same http://www.westernthunder.co.uk/index.php?threads/dikitrikis-dark-side-l-y-crab-temporarily.100/page-11

...

Richard, that thread is fantastically helpful.  I probably should content myself with getting slick motion rather than attempting to replicate all the detail your skills create, but still, nothing like aiming high!

 

The patriot valve guides are very different to the rebuilt Scot and the comparison of my kit ones to the pics of your rebuilt Scot ones make me think mine are slightly inferior in quality but I think I'm going to put mine together 'as is' and hope minor imperfections in the castings are lost in the overall impression of the model.  Over the weekend I should get time to assemble them and you can critique what I've done.

[t-b-g]

One method I use when assembling valve gear is to use chemical blackening. I treat one part, then I can solder a pin through with no need for any foil/paper etc. I can get the joint as tight as I like and I can get several does at it. Solder will just not "take" to a blackened surface and I find it a useful technique in a few areas of modelling, such as building signals.

 

Then, when I am happy with the soldered joint, I treat the whole lot. Much better than paint and using Birchwood Casey blackening and a good polish, either Nickel Silver or Brass etched gear looks a lot more like steel.

 

Tony

[dikitriki]

The instructions talk about using the motion support bracket to help align everything. Does this mean I could 'cheat' on the slidebar/cylinder join (see post above) and use the assembled motion bracket to help align the cylinder/slide bar assembly? I think the slight inclination of the cylinders required would be unnoticeable (one side very slightly low, the other very slightly high), and the slidebars are held at the non-cylinder ends by the motion bracket so they *have* to line up at that end.  So I'm thinking of assembling the motion bracket next, before trying to relocate the slidebar to give an idea of how far off everything might be and possibly save some angst.

Hi Tim,

 

Yes and no!

 

I assume that the front and back cylinder faces are parallel, and that the location of the end of the cylinders attached to the slide bars is in the same place on either side in relation to the cylinder cladding.

 

If that is the case, place the cylinder on a flat surface - in the orientation as above, and make sure each slide bar is truly at 90 degrees to the flat surface. Your will be able to tweak the individual slidebars by simply bending them using a pair of smooth nosed pliers to the correct position, as they do not appear to be too far out. Once they are all at 90 degrees viewed from both side and top, re-check that the crosshead is a nice sliding fit. Then ensure that the slidebar support bracket fits round the slidebars without forcing them in any way, and only then mount in the chassis and use both at the same time to get the correct fit in the chassis.

 

Put a 2mm rod or similar through the piston hole with the extension aligning with the centre of the middle driving axle (a little difficult if you have CSB!) and if the rod is parallel to the slidebars, the cylinders and support bracket are properly located, with the cylinders at the correct angle. Fiddle and file until this is achived and the cylinders are sitiing properly in the chassis and not interfering with the fit of the footplate.

 

Richard

[Grasshopper John]

On my build Tim I assembled the front and rear motion brackets before the slidebars, as the front one will have a recess for the slidebar which may or may not have a slightly downward slant for the slidebar, this reduced a little bit of reassembly for me, although not a lot

[Tim2014]

Well, where'd a fortnight go?  I think Grasshopper John thought I'd thrown in the towel! No fear, but I've been lazy about detailing my tribulations.  I think on a previous post I said I was pretty confident about where I was heading with the valve gear...but it's been two steps forward and one back.  I know what I'm trying to achieve, but the number of steps to get there, and the order to do them in, is certainly something that has been underestimated!

So, here's what I've struggled with:

The cross-heads took a huge amount of fettling to get to this point where the connecting rods sits flat against them at the right point and pivot nicely. 

In fact I had to buy a special dremel grinding tip (it's *tiny*) to get in there and remove what was a solid web between the pin and the main casting.  I did consider drilling the existing cast pin out and that may have been an easier option.

 

I've relined the valve guide centers with brass tube to get the slides better aligned with the support brackets..I'll detail that in due course in case anyone else is lucky enough to get castings like mine.

 

Having got the cylinder wrapper and castings all beautifully aligned I dropped it, with the large adjustable wrench/heatsink still on it.  This didn't help the alignment, and I really thought might be irretrievable.  A workbench is a good idea, it slid off my knee, only 2 ft onto carpet, but with the 0.5kg of the spanner behind it and a 'bend here' slot in the support frame!

 

The final step backwards was because I did my final assembly of the right hand coupling rod by building it for the left side.  I nearly left it, but the chassis wasn't as free rolling as it had been - presumably because the coupling rods have very slightly different spacings so not everything is exactly square.  So these pics are actually the same coupling rod, but on different sides of the loco!

As first built:

As now (about 1 week later!):

Guess who didn't check the other side of the etch before cutting out the boss for the coupling rod? I'll have to fill the 'A' with solder, it shows through even when it's on the 'proper' LHS of the loco.

 

The rest of the time has been just tackling the problems that arise, although I did a powered test, it was before fitting the brake gear and that needed to be finished off to get the bits of rodding out of the way of the coupling rods.

 

I'm very glad I heeded the advice of Ozzy et al. and laminated extra bosses onto the coupling rods.  They look so much more bulky than they would have, and in fact it's probably necessary for the clearances off the wheel faces.  But that raised an issue with the center wheel, which has no extra bosses in the kit. My solution was to cannibalise the spare 'original style' rods:

 

I had to fabricate bosses for the connecting rods, although only one is made up so far (I'm still on step 1 of Richards recommended order in the post above!).

I've also modified the pivot area of the coupling rods considerably, not sure it's worth the trouble.  So like British Rail waaay back.  "We're getting there". They never did, but I hope I will!

 

My new pivots on the coupling rods do seem to have created a few tight spots, which is what I was worried about. I really should have got the coupling rods to this point *before* doing the hornguides. Hopefully a little fettling can sort it out, I'll be doing a powered test shortly.

Edited June 11, 2015 by Tim2014

[t-b-g]

After some 35 years of working pretty much exclusively in 4mm scale I am just dabbling a little bit in 7mm so I am keeping an eye on one or two 7mm threads.

 

I am really enjoying watching your progress and I find your approach to the build, being willing to go that extra mile to improve the kit and to get things right, highly motivational!

 

I can just tell that the finished Scot is going to be quite lovely!

 

Tony

[dibateg]

It's a slippery slope Tony! Look out!

[t-b-g]

It's a slippery slope Tony! Look out!

 

And you are partly to blame!

 

I had been having strange thoughts about doing a bit of 7mm for a while but it was seeing your locos when you took them to Geoff's when we had that running day that tipped me over the edge and made me go for the wallet!

 

Mind you, mine will be all clean and shiny in GCR pre-grouping livery and not all mucky like yours.....

[Tim2014]

It is indeed a slippery slope Tony - beware as right now I'm well and truly in the mire!  Thanks for your encouragement though, maybe one day I will actually finish it, but it seems a long way off right now!

 

As I feared, redrilling the coupling rods to accept thicker pivot pins has stuffed their lengths, the wheels now bind up. Not locking tight, but certainly nowhere near as smooth as they were.  I've stripped everything down and put the axle jigs back in and that locks up the CSB solid. The jigs have twice as much thickness of rod to go through as they did when I set the hornblocks up and I realised that the holes for the Slaters bushes might not be square any more so I will check that by inserting bushes with brass rod through the middle.  That will also enable me to measure the lengths of each rod and compare back to the wheelspacing measurements I took originally (they both look exactly the same by eye).  If everything is square I think I have two options: lengthen the rods (assuming they are now too short), or move the hornblocks.

I'm still waiting on "etched loco construction" to arrive - assuming it goes into this sort of thing.  So in its absence, any pointers would be appreciated.  From some browsing it sounds like you can gently hammer a rod to lengthen it (yikes) and oval out a hole to give a bit more side play. Neither sound ideal and both seem to have the very real risk of making the problem worse.  Again, with hindsight I should have got the rods pivoted and then checked the rolling chassis before working on the fluting, now if I take any heat to the rods (to take off the bosses for example), all the filling and filing on the fluting will have to be redone.

Lastly, I have checked as a coupled 0-4-0 and it's fine on the front wheels, the back is trickier to check because the CSB means the front needs supporting (I should probably refit the bogie) but I'm pretty sure it's the rear jointed section that's causing my problems.

 

Uncoupled diesels suddenly seem a lot more appealing than they did!

[Grasshopper John]

Tim, dont know if this helps but i drilled my coupling rods out to 2.7mm to give a bit more room for the 2.4mm bush ( top hat ) its plenty to give a nice action.

[Tim2014]

Tim, dont know if this helps but i drilled my coupling rods out to 2.7mm to give a bit more room for the 2.4mm bush ( top hat ) its plenty to give a nice action.

Thanks John, that might well help, a 2.5 mm drill doesn't fit through my rods atm. AND it looks like the holes thru them aren't square with the bosses on.  Tim might be happy again by the end of the evening...

[Tim2014]

Yay, drilled out to 2.6 mm and it's much, much better. There's still a tight spot on the LHS with the coupling rod at 3 o'clock, but I think I'm on the right track now. Thanks John.

[Grasshopper John]

Glad it worked Tim, as a good friend always says there's always an escape route

[Tim2014]

I’ve alluded to difficulties with the valve guide castings in my kit.  They looked out of true to me – the crosshead bracket is angled upwards compared to where it should be and the valve spindles sat well below the center of their guides (in the vertical plane), as well as being off center laterally.  I decided not to condemn the castings and bored out the gland enough to allow a new guide tube to be soldered in to realign everything.  Thanks to Jeff P somewhere on here for that suggestion.  He was talking about supporting piston rods, but it’s the same principle here. 

This doesn’t really show how bad the problem was initially, but hopefully give the general idea:

 

And this hints at how much material had to be removed to allow realignment:

 

The castings were quite pitted too so I ‘handed’ them to leave the best side visible when fitted to the loco, and then tried to fill the worst of the pitting that would be seen with solder, supporting the spindle with some scrap tube that was a close sliding fit.  As you can guess, there was a *lot* of solder flowed in to hold it centrally.  It took a few reheats to get things lined up satisfactorily, but wasn’t too hard in the end.

Before cleaning up and trimming:

 

And the final result (from the ‘wrong’ side obviously, wasn’t thinking about that when I took the photos!):