7mm Gladiator Royal Scot build

[Tim2014]

This was my problem with the coupling rods:

 

Drilling them out square sorted it, I think it was just stray solder that 'filled' the holes slightly, combined with a bit of error lining the bosses up exactly, compounded by the fact that the rods foul the brake bracket covers veeery slightly with max sideplay. I need to decide whether I can reduce sideplay, or need to skim some material off the brake brackets. I need a spark gaps clearance at least!

 

Now onto the motion brackets so I can get the eccentric rod and return crank sorted.  Tim's happy again

[Grasshopper John]

Tim, you need to use a Pin chuck to widen holes in coupling rods and conn rods, put them on a small piece of wood and use your eye.

[Tim2014]

Tim, you need to use a Pin chuck to widen holes in coupling rods and conn rods, put them on a small piece of wood and use your eye.

Thanks John, I used a pin chuck both times around but didn't rest it on backing wood - maybe that was part of my problem.  I think I put too much trust in the alignment of the frets 1st time around thinking they'd guide the drill and it would just remove the solder. Having checked the alignment as per above pic, I knew which way I needed the hole to ease and so 'leant' on the drill shaft gently as I drilled it out and that seemed to work.  I've looked carefully now and the LHS boss is a little too far towards the top of the pic so must have slipped a little when clamped together for soldering and that probably then 'steered' the drill off so it actually needed some etch removing as well as solder.

[Tim2014]

Can any detail aficionados help with a question about the area between the slidebars and the bogie wheels?

Full size photos make it looks like it's not empty space between the rear bogie wheel and the slidebars/crosshead.  That makes a lot of sense since presumably you don't really want crud from the wheels spraying up into that area.  If that's the case, you'd never see daylight between the slidebars, nor the top of the bogie wheel as I see in most models. But if there is a 'guard' of some sort there, what shape was it?

Edited June 18, 2015 by Tim2014

[Grasshopper John]

Clamps tend to 'Move' things as you tighten them Tim, get yourself some of these spring clamps, cheap and do the job.

 

 

PS there's nothing between the rear bogie wheels and the front of the cylinders on my build, there isn't enough room for anything

[scot6p]

Hi Tim on the prototype there is a spasher guard between the rear bogie wheel and slide guard. It is a smaller version of the wheel spasher (3'1/2"cut in half).

 

Len

[Sandy Harper]

Can any detail aficionados help with a question about the area between the slidebars and the bogie wheels?

Full size photos make it looks like it's not empty space between the rear bogie wheel and the slidebars/crosshead.  That makes a lot of sense since presumably you don't really want crud from the wheels spraying up into that area.  If that's the case, you'd never see daylight between the slidebars, nor the top of the bogie wheel as I see in most models. But if there is a 'guard' of some sort there, what shape was it?

slidebars.JPG

Tim

It looks like a mini splasher. You can see what look like bolts which appear to show it attached to the main frame.

Sandy

[Guest Isambarduk]

"Clamps tend to 'Move' things as you tighten them Tim,"
 
These clamps don't move:
 

 
They are not as cheap as the ones that John illustrates but they are not that expensive and they are really useful at holding all sorts of things in place whilst you work on them.
 

 

See here, for example:
http://www.ebay.co.uk/itm/TOOLMAKERS-CLAMP-2/111601960711?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20141212152715%26meid%3D119ce868326a44b6b4f5c19517302f79%26pid%3D100338%26rk%3D2%26rkt%3D30%26mehot%3Des%26sd%3D291426879918

David

[Grasshopper John]

They look the business David, Never seen them before, I was referring to G clamps which I've tried with little success.

[N15class]

You can always set parts up parallel in them too. I some times use mine for setting up frames.

[Guest Isambarduk]

"I was referring to G clamps ..."

Ah, I did wonder but that would explain it!  These are toolmakers' clamps and they are ideal for much of what we do when it come to holding flat things.   David

[JeffP]

I believe they are known as "tool-maker's clamps"?

 

http://www.ebay.co.uk/sch/i.html?_odkw=pattern+makers+clamp&_osacat=0&_from=R40&_trksid=p2045573.m570.l2632.R2.TR3.TRC2.A0.H0.Xtool+makers+clamp.TRS0&_nkw=toolmakers+clamp&_sacat=11804

 

http://www.amazon.co.uk/Faithfull-Toolmakers-Clamp-30mm-1-1/dp/B0006JJQJQ/ref=sr_1_1?ie=UTF8&qid=1434643633&sr=8-1&keywords=tool+makers+clamp

 

Other outlets are available.

[Grasshopper John]

Thank you David, you know I can't resist a good tool, just purchased a couple of 1 3/4 " ones, You can never have to many tools in this hobby

[Tim2014]

Thanks folks looks like I need to invest in some tool-makers clamps!  I've been using alligator clips (did I say 'clamps'), and the serrated teeth and non-parallel nature of the jaws can mean things slip, but I've generally got on OK with them and they are cheap and light.  It would be good to also have some heavy duty accurate ones in the arsenal though.  I also use the alligator clips as heatsinks near joints that are at risk of desoldering.

[Tim2014]

Just thought I’d show what Dikitriki alluded to in an earlier post regarding a 2mm rod through the piston to check alignment of the cylinders relative to the driving wheels.

 

That is a little trickier with CSB, but not too much.  I’m lucky, the temporary spring I have in at the moment is just right for the current chassis weight to keep everything at the right height.  If it weren’t I can think of two options and there are probably others:

1 Put the real spring in and weight the chassis fore and aft to simulate the finished weight (checking your CSB calcs at the same time!).

2  Make some ‘chocks’ to sit between the top of the hornblock and the hornguide to keep the hornblocks at the specified ride height.

I’ll use the second method next time.

[Tim2014]

So the coupled wheels turn, the cylinders and castings are on and located – now for the front motion bracket.  As John found with the Black 5, it takes a fair bit of fettling to get the bracket in the right place without moving the slidebars enough for the crossheads to bind when they were once gliding smoothly.  But we got there after a little fiddling:

 

The entire motion bracket assembly with cylinders are in one piece and removable in this kit, definitely a big plus I think.  I’m planning to have most of the assembly permanent, removing the return crank and coupling rods to then detach it from the rest of the chassis if required.

Here are the remaining components of the bracket.  The brass motion supports are tricky to fold up.  I did the first forgetting I’d bought a set of metal folding pliers.  That made the second one a lot easier

 

Note the rear N/S bracket, as assembled there which caused this:

 

I think the problem is with the etch of the bracket itself, it sits too high in the chassis, even with the lip in the previous pic filed away.  I delaminated it, unfolded the mounting brackets and ‘rescored’ thinking I might be able to refold them , knowing they’d probably break off:

 

In the end I snapped them off anyway and filed the bottom of the bracket down until I could get the bracket to fit nice and low (I can chock it up to meet the footplate easy enough with spacers, but there’s no way I can make it lower unless I sort it now). I then soldered it to the brass motion brackets even though it wasn’t screwed down.  Finally (be still my beating heart!) out with the first rizzla paper to solder the mounts back onto the bracket.  I knew there was a good chance I may have to unsolder it from the brass motion brackets to readjust the alignment, but figured that was no real problem:

 

And here it is – a substantial piece of metal work now – the rizzla and sharpie worked like a dream, thanks folks!

 

Next up is radius rods, expansion links and eccentric rods, though I have realized I should have cut the valve guides down as I can’t get them out without removing either the valve casting or the front motion bracket!

[ozzyo]

Hello Tim,

 

you have mentioned about removing parts of the valve gear. Why should you need to do that unless your loco is going to run 100s of real miles? All it should need is a drink of oil after say 20 or 40 hours of continuous (is that spelt right) running.  

It's a bit like saying that the axle boxes should be made re-movable all they need is a bit of good oil after 10 to 20 hours of running.

 

All I will say is if you keep up a good lubrication régime on your loco the chances are you will not have to replace any bearings unless you are about aged 10 and your loco is aged about 50.

 

OzzyO. 

[Tim2014]

Hello Tim,

 

you have mentioned about removing parts of the valve gear. Why should you need to do that unless your loco is going to run 100s of real miles? All it should need is a drink of oil after say 20 or 40 hours of continuous (is that spelt right) running.  

It's a bit like saying that the axle boxes should be made re-movable all they need is a bit of good oil after 10 to 20 hours of running.

 

All I will say is if you keep up a good lubrication régime on your loco the chances are you will not have to replace any bearings unless you are about aged 10 and your loco is aged about 50.

 

OzzyO. 

Well, so far being able to undo bits when I stuff them would be handy

Seriously though, you ask a good question.  I've always had my locos in bits regularly for as long as I've been modelling, when I was younger that was usually because I was curious about how they worked, more recently it's to 'tweak' them adding lights/smoke/details.  When I started building this kit, I thought people just built them with 'disconnection' points and never really thought much more about it. I had been planning to use small nuts and bolts extensively on the valve gear, thinking that would facilitate the process, but as I gradually assemble it (to see how much clearance and what alignments are needed) and compare to prototype photos, I've come to the conclusion that small soldered washers and riveted joints are going to give a much better look and freer, less sloppy joints without the worry of threadlocker (which I find is great if you get it in the right place and don't ever need it undone, but I usually find at least one of those is not the case!).  Sure, having to desolder things isn't ideal, but it's not that big a deal either and certainly no harder than fiddling with small nuts and bolts (I've decided 14 BA is my limit with middle-aged eyesight).

 

So obviously, at some point I'll need to paint it and weather it, and I can see that running with minimal valve gear could be useful for troubleshooting etc. But apart from that would you say that regular disconnection of valve gear sub-components is not necessary?

[Tim2014]

Following on from that:

I was planning to use a non-permanent thread locker on the return cranks - very carefully, and permanent thread locker on the front and center 10BA screws thru the wheels.  I haven't yet committed to the front bush design, it'll probably be two holes and done up tight as per Dikitriki and others, but I may slot it in the short term.  It's tempting though to think a small dab of superglue in the bush center once done up finger tight might be enough and avoid the need for tooling points on the bush.  You'd probably have to replace the bush if you ever did want to get it off, but I think my budget can stretch to that

 

Finally, being able to remove the valves spindles from their guides at this stage *is* important for me because I found combination levers didn't have quite enough fore-aft 'swing'.  They fouled the top and bottom of the valve spindle fork which needed a little more material filing off.  I'd already riveted the two together in a rash fit of enthusiasm before fitting the front motion bracket which would have been OK, had there been enough travel and had the combination lever not needed any bending to fit nicely around the slide bars.  I would definitely advocate trimming the valve spindles to the max length to still allow them to be inserted and removed with the front motion bracket soldered to the slidebars.  For me that was around 17.5 mm overall length, including the fork, and I should have checked and cut both just before soldering the front bracket to the slidebars (step 47), whereas the instructions only mention trimming the valve spindles in step 53, which I'd read, but being far into the distant future, largely ignored and certainly not fully understood until presented with my problem.  In the end, I pulled the valve guide casting, spindle and combination lever off because I wasn't happy with the casting alignment.  I'll probably do that to trim the other sides valve spindle too since it wasn't that hard to do.

 

In response to anticipated mileage: I am envisaging a lot of running (one day!), my track is an outdoor 35 m loop and when I run, I like to watch the trains go by, so 20 laps a session, 20 days a year is a likely scenario.  But even then, it's only 14 'real' km a year, so probably no big deal.  If I wear the valve gear out through over use, I'll just have to build another set, t'will be good practice

Edited June 23, 2015 by Tim2014

[Horsetan]

.....being able to remove the valves spindles from their guides at this stage *is* important for me because I found combination levers didn't have quite enough fore-aft 'swing'.  They fouled the top and bottom of the valve spindle fork which needed a little more material filing off.  I'd already riveted the two together in a rash fit of enthusiasm before fitting the front motion bracket which would have been OK, had there been enough travel and had the combination lever not needed any bending to fit nicely around the slide bars.  I would definitely advocate trimming the valve spindles to the max length to still allow them to be inserted and removed with the front motion bracket soldered to the slidebars.  For me that was around 17.5 mm overall length, including the fork, and I should have checked and cut both just before soldering the front bracket to the slidebars (step 47), whereas the instructions only mention trimming the valve spindles in step 53, which I'd read, but being far into the distant future, largely ignored and certainly not fully understood until presented with my problem.  In the end, I pulled the valve guide casting, spindle and combination lever off because I wasn't happy with the casting alignment.  I'll probably do that to trim the other sides valve spindle too since it wasn't that hard to do.....

A similar problem was also identified in the 4mm scale Brassmasters kit (see MRJ 149), where there was some uncertainty as to whether the valve spindle crosshead guide and its attached support to rear piston valve chest casting was too long.

[ozzyo]

Well, so far being able to undo bits when I stuff them would be handy .

But apart from that would you say that regular disconnection of valve gear sub-components is not necessary?

 

I would say that once you get the valve gear set up and running right you should not need to break the valve gear down in to sub-components.

 

Following on from that:

I was planning to use a non-permanent thread locker on the return cranks - very carefully, and permanent thread locker on the front and center 10BA screws thru the wheels.  I haven't yet committed to the front bush design, it'll probably be two holes and done up tight as per Dikitriki and others, but I may slot it in the short term.  It's tempting though to think a small dab of superglue in the bush center once done up finger tight might be enough and avoid the need for tooling points on the bush.  You'd probably have to replace the bush if you ever did want to get it off, but I think my budget can stretch to that

 

In response to anticipated mileage: I am envisaging a lot of running (one day!), my track is an outdoor 35 m loop and when I run, I like to watch the trains go by, so 20 laps a session, 20 days a year is a likely scenario.  But even then, it's only 14 'real' km a year, so probably no big deal.  If I wear the valve gear out through over use, I'll just have to build another set, t'will be good practice

 

You could use nail varnish to lock the return cranks in place.

 

For locking the 10BA screws that I use in place I use Loctite 290, as seen below.

 

On some locos I also use it on the tapped top hat bearings.

 

On the front bush you could use Loctite 290 on this as it's a wicking type adhesive. Down side is it one of the strongest in the Loctite range, about the only way you can get parts apart again is to use heat.

 

OzzyO. 

[3 link]

Slightly off topic Ozzy, my wife says please trim your nails or next time she sees you she will pin you down and cut them all off......

 

Martyn.

[Tim2014]

Sorry folks, it's been a while!

That nail varnish has been a great help Ozzy.

 

I can report I have finally got one sides motion working to my satisfaction.  It's still not 'complete', but I know it can be in due course. What took the time? Well, other than just being slack on the modelling, I have to confess to a little bit of ego.

 

Before I started this build I didn't even know steam locomotives had a reverse gear, I'd never really thought about it.  So once I found out how Walschaerts works I became fixated on the idea of having the reversing gear hooked up to an actuator to move the radius rod! I have now seen common sense, but only because I want to finish this kit and I could see myself being bogged down in the detail for a looong time so that's for another day (or model).  Although I do know I could do it on this, linking the two sides together would be very awkward.  I got as far as figuring out how to make the expansion link accommodate a fully pivoting radius rod and decided enough was enough for a first build.  It also seems to me that it's not a simple forward, neutral, reverse system. Presumably it's a bit like ignition timing with an internal combustion engine and a bit of 'advance' or retardardation gives the driver some finesse.  Most of the pics of Scots at speed that I can find seem to show the radius rods almost in the neutral position so I really like the idea of having that linked to engine speed (or load).

 

Other things that have caused me grief are the *many* small areas where tolerances result in something binding at one point in the travel. But I've got there eventually, and the other side should be fairly quick as a result.  The motion bracket is still not soldered together as I think the cylinders and front motion bracket are sitting too 'deep' or low relative to the chassis top.  I think I'll make a start on the valances and footplate to allow me to confirm that, otherwise I'll be soldering the motion bracket up just to maybe find out that it needs to come apart again.  Having the footplate and valance in position will allow easy comparison to prototype pics, and if the front is right, I'll need to modify the rear motion bracket to get everything sitting right.  I hope it's the rear that needs modifying since the front will be more work involving the slidebars, cylinders and the angle to the center drivers.

Anyway, this is what it looks like at the moment with just the anchor nut for the eccentric rod to return crank to do, along with a few final solder joints which can wait until the very end.  You'll see the 'high' rear of the motion bracket (or is it a low front?).  At that height the center wheels just hit the bracket on full deflection and the coupling rods just miss the pivot for the reversing shaft lever.  I can adjust that height of the pivot point quite easily, but it's already 'high; compared to how I think the etches would naturally assemble, but low (close to the wheels) compared to prototype placement and the instructions schematic:

 

 

I've found the Ragstone brass rivets to be very handy, along with the brass nails I alluded to in an earlier post and have ended up using only one of my 14BA nuts and bolts so far, and that's on the expansion link to eccentric rod joint.  Now I'm clear I shouldn't have to do much dissassembly, I'm pretty happy soldering everything in place (as long as it's not fixed solid!).

 

I can recommend Bob Pearman's excellent service if you need books and now have a copy of etched loco construction, the Book of the Royal Scots, and a couple of relevant magazines which have all been most helpful (although I was surprised that the etched loco construction book defers to another publication for details of chassis building   The rest of it is just-in-time!

 

[Tim2014]

A similar problem was also identified in the 4mm scale Brassmasters kit (see MRJ 149), where there was some uncertainty as to whether the valve spindle crosshead guide and its attached support to rear piston valve chest casting was too long.

Thanks Horsetan - since I lack even scale drawings, I'll have to leave it to others to make that call (I've got the calipers out against some prototype pics to work out dimensions when I've needed too, but the errors will be pretty large!).  The amount of work in designing a kit like this must be astronomical so I don't want to seem overly  critical, especially with my ropey assembly skills!  I'll do the best I can on the assembly and hope any deficiencies there may be fade away in the overall impression of the model. I'm certain that pretty much all the shortcomings will be from me as a builder rather than the kit!

[Tim2014]

A short update:

I've been thinking about what Ozzy said about threadlocker.  I've got some loctite 243 and have used it a fair bit on full size cars. I'd be feared using even that on a model for anything I wanted undone one day, and being anerobic it would need to be put on very carefully. It feels a bit like a sledgehammer to crack a nut for valvegear. I reckon I might stick with nail varnish for now and upgrade to a threadlocker if/when something comes loose.

 

As far as the front and rear motion brackets goes: I looked back to Dikitriki's really helpful shots of his Scot (earlier in this thread) and realised (as always!) there is another option for me: notch the rear bracket support to allow the motion support brackets to sit parallel to the top of the chassis while leaving the cylinders and front motion bracket as they are.  That is doubly attractive because I can actually even raise the rear motion bracket a little to keep it clear of the wheels.  Once again, leaving things for a bit for the brain to mull things over in the background has come up trumps (probably!)