Another Beyer Garratt 0-4-4-0

[Giles]

Looking good Simon, I take it you'll fit a three-dimensional throat-plate before fixing anything down, as that will increase the overall length?

 

To whet your appetite, mine made its first public debut at the weekend and Tonbridge on Martin Coombes 'Theobalds Yard'

 

 

[Simond]

Hi Giles,

 

Thanks for the thoughts: the throatplate will fit outside the barrel, so the length is now fixed (and right!!!). Jury's out on material. I might adapt the whitemetal one provided with the kit, or use plastic, or break another 5 fretsaw blades doing it in brass...

 

What a fun layout! The Garratt looks fantastic, & I'm going to try to emulate your polished paintwork in due course, but my efforts to date have been less than wholly satisfying. I love the interlaced & dual gauge track. I saw the TK in the background, too, I think.

 

Have been drawing frames today, amongst other things. Hope to get them finished tomorrow and will then knock up a mock up in plastic, prior to lasering the acrylic masters for the pantograph.

 

Think I'll turn the wheels today, and maybe short them out.

 

Best

Simon

[PhilMortimer]

I think I'm quite pleased with myself!

 

And so you should be! It looks great

[Simond]

Well, less "wheel" progress than I hoped for as it seems that my milliput might have been a bit long kept, and some of it hasn't set properly - I suspect this was bits of a "skin" that had formed on one part of it, and despite thinking I'd mixed it well, I clearly haven't done it well enough, and I'm left with sort-of rubbery inclusions.

 

The turning went much as planned, herewith gratuitously posed photo of the trusty Unimat (if anyone offers you one of these, my advice is to buy it!)

 

 

I set up a spare axle in the 3-jaw, and was able to turn the outside diameter on all 8 wheels followed by the face on all 8 wheels at the same settings, by changing the wheels. A lot of screw twiddling, but they're all the same, which helps.

 

Unfortunately, I've had to dig out the crappy bits of unpolymerised Milliput, and now need to get some new, in order to finish the job.

 

 

Irritating, but not a crisis. When I bought my Unimat, it came with lots of extra bits (but unfortunately not all the bits to convert it to a milling machine), one of which is a dividing head. This will see service when it comes to drilling the three holes in the balance weights. But I have to fix the Milliput issue first!

 

I shall measure up the hornguides to transfer to the CAD tomorrow. Steph Dale etches, Slaters 7961 insulated hornblocks.

 

 

All set for sprung axles & split axle pick-ups.

 

Best

Simon

[Giles]

Fascinating - I've never seen Milliput go like that before! Or not..... still, as you say, not a disaster.

 

Regards the paintwork, there are no short cuts to actually using a pad of 2000 grit wet-and-dry and dry to achieving the effect. I know some people just Polish instead, but that doesn't do the same thing.

 

I agree entirely about the Unimat 3 - I have one, and it's such a useful little machine (I remotored mine with sheep-sheering motors adapted with variable speed, which have been brilliant over the years. They run cool, are more powerful, and by adding a pot, give me variable speed)

[Simond]

Further progress on the wheels. Just as well, as the CAD for the frames is not being wholly cooperative. Or maybe it's just me.

 

The pal with the pantograph suggests 1 or 1.2 mm for the frames, which seems entirely reasonable, and which will do nicely for the cylinder formers too. Trouble is, this is way too thick for the motion brackets, the sandbox bracket, and the stiffener behind the buffer beam, all of which probably want to be 0.5mm, with half-etched fold lines in places - cutting from 0.5mm isn't a problem, but etching with a miller is likely to be more trouble than it's worth! (I have considered "half milling", it's at least theoretically possible, but not a realistic solution).

 

I bought Steph Dale's hornguides, to suit the Slaters insulated hornblocks. I'm not sure that the hornguides are going to fit this chassis very well, so I might keep them for the next project (or the one after that, there are 3 GW loco kits in the cupboard) and manufacture something to suit. So there's a deal of pondering, and a deal less progress in that department. I shall probably knock up a pair of plasticard bogies to try out my ideas before cutting metal. Shame is that the templates are not going to be done for Kettering, so that means more delay

 

Anyway, progress on the wheels. Like Giles & Phil before me, I opted not to use the balance weights that the kit included and made substitutes from Milliput. After a slight false start, I managed that, and have now drilled the three holes in the face. Technology to the fore, I assembled the dividing head and 40-hole plate from the Unimat to the Proxxon milling table in the TBM. Scaling from a photo suggested that the holes should be 6mm from the centre and 1.8mm in diameter, and it was pretty easy to achieve this using this set up, the only difficulty being the length of my 1.8mm drill, which meant that the TBM head was right at the top of the pillar.

 

 

 

 

In the last photo, the observant will note that there are rather fewer holes... this was due to a misjudgement, led astray by the etched balance weights. I had previously decided that 36 degrees was the correct angular spacing... and allowed myself to be convinced, temporarily, that a smaller angle might be better. Having drilled one, and compared it to prototype photos, I reverted to plan A, and the two erroneous holes have been refilled with Milliput. Final drilling tomorrow, which means that the shorting of the wheels will have to be delayed.

 

So now I'll have a go at Steph's method for split axles... http://euram-online.co.uk/tips/splitaxle/splitaxle3.htm

 

I purchased the glass fibre rod from EC Fibreglas, who were very helpful - a metre of 2mm rod is a whole 99p, but the postage is about £8, so they kindly cut it up for me, so it went in a normal Jiffy bag, and the whole cost reduced to about £3.25.

 

So now, araldite, oiled screws, axles...

 

Best

Simon

[Simond]

Or not...

 

I had prepared the axles last week, but had not yet drilled the cross holes. Steph talks about them as being there for added glue grip, but they are possibly even more important to let the excess glue and any air out.

 

And the TBM is set up for the remaining wheel. So stalled.

 

So watching Chris Tarrant's program instead. Rather disappointed with it, in a vaguely dissatisfied way. Still, some very good historical pictures!

 

Best

Simon

[Giles]

Forgive me asking, but are the half-etch lines all absolutely necessary? If you assembled your new frames with conventional frame spacers - be they temporary or permanent- and then solder or silver solder the beams on, that would be practical. With beams, I myself would silver solder angle to the beams first to provide location etc....

 

Just a thought- forgive me - I'm sure you've thought all this through anyway!

[Simond]

Giles

 

Thanks for the thoughts

 

It's easy to do one, or even two, but it would be nice to be able to offer an engineeered solution to anyone else who walks this way, and getting suggestions helps.

 

For me, the half etch is not necessary and I can certainly build a pair of engines. For anyone else, it would be "an aid to scratch building"

 

hence the thinking out loud

 

Simon

[Simond]

Wheels now connected from rim to hub, blacked, the balance weights coloured with Indian ink, and the steel has been oiled.

 

One pair of axles turned to isolate the ends from the middle, to go on the gearboxes, and the other pair isolated in th middle as it's likely to be rather stronger. I found the whole process a bit scary, as I'd never tried it before, but it all seems to work much as expected. I ground a very narrow knife edge tool to part the axle around the fibreglass rod, and have now filled the resultant groove with more Araldite. I'll clean up the axles tomorrow. I was surprised just how stiff the axles were, even with the grooves cut in them.

 

If & when I do it again, I'll certainly use wheels that aren't insulated. It's all do-able, but it seems daft to start as far from where you want to be as you can. To connect the hub & rim, I used tinned copper wire, a drop of rosin flux at each end, and used the RSU to get the heat in quickly. All seemed to go according to plan.

 

Herewith some pix

 

 

 

 

The chassis CAD is progressing a little better, and I'm pretty sure that I now have another cunning plan... but unfortunately, there is no realistic possibility of making the plasticard mock-ups, adjusting the CAD, and cutting the templates before Kettering, so I'll end up posting them. No big deal.

 

All the best

Simon

[Simond]

Herewith yesterday's photo of the wheels, axles, and axleboxes, all prepared.

 

 

Today's trip to Kettering resulted in limited purchases, a pair of Laurie Griffin's Wakefield lubricators, a set of buffers from Graham at NMRS (they're actually for a Sentinel, but removal of the footsteps will make them very suitable), and some washout plugs and other boiler fittings from Billy at Premier Components.

 

It was very nice to catch up with many friends and acquaintances, and to meet a couple of people with whom I'd only corresponded on here, the GOG website or Western Thunder - one of the joys of the shows.

 

A little light plasticard engineering this evening, making a dummy set of engine frames to test the CAD.

 

Best

Simon

[Giles]

Sorry I missed you at the show. Those look excellent to say the least...

 

Can't wait to see your frames!

[Simond]

Giles

 

Didn't realise you were there, shame. I did see your End of the Line, it's as good, even better, in the flesh as it is in the photos!

 

Telford?

 

Been doing a bit of plastic frame assembly this morning. Very pleased that I did, as there are a couple of mods I want to make, already, and we haven't got to the difficult bits yet!

 

Best

Simon

[Focalplane]

Simon

 

I like your pickup set up, but have a question - does a thin film of oil on the bearings cause problems for conductivity?

 

I missed Kettering as well, a pity as when in England it is probably the closest GOG venue to home.  And Telford's timing is never so good for us as we are usually recovering in France from having family around all summer!

 

Paul

[Simond]

Thanks Paul,

 

I don't believe it will be a problem, for both theoretical and practical reasons:

 

Theoretically, the microscopic irregularities (asperities) on both axle and bearing bush will make contact as the lubrication is marginal at best. The rubbing speed is far too low to generate any kind of hydrodynamic effect.

 

Practically, the Hornby and Tri-Ang trains of my childhood used exactly this kind of contact for one (or both) rails and they certainly didn't have any issues! Lots of modellers use split axles, precisely because it gets away from all the issues to do with dirty pickups, collection of fluff & muck, etc.

 

It's the second one I've built, my 28xx uses sprung split axles (and split frames) on the tender, which was a bit of a faff to set up, but works very well. I've also fitted lighting to a rake of toplight coaches, and used "American" pickups, with the wheels shorted on one side of each bogie. You can find these, and lots of other entertainment, in my Porth Dinllaen thread, link below.

 

Best

Simon

[Focalplane]

Thanks Paul,

 

I don't believe it will be a problem, for both theoretical and practical reasons:

 

Theoretically, the microscopic irregularities (asperities) on both axle and bearing bush will make contact as the lubrication is marginal at best. The rubbing speed is far too low to generate any kind of hydrodynamic effect.

 

Practically, the Hornby and Tri-Ang trains of my childhood used exactly this kind of contact for one (or both) rails and they certainly didn't have any issues! Lots of modellers use split axles, precisely because it gets away from all the issues to do with dirty pickups, collection of fluff & muck, etc.

 

It's the second one I've built, my 28xx uses sprung split axles (and split frames) on the tender, which was a bit of a faff to set up, but works very well. I've also fitted lighting to a rake of toplight coaches, and used "American" pickups, with the wheels shorted on one side of each bogie. You can find these, and lots of other entertainment, in my Porth Dinllaen thread, link below.

 

Best

Simon

 

Simon

 

I thought you would be right, but having no experience of the system was interested to learn of your experience and explanation.  It all makes sense.  Most of my early white metal kits (4mm) had the American system, including one American prairie which I still have somewhere.  Others included a Wills Finecast King and 4F, both of which are stored away.  But I have never contemplated split axle pickups, but it would be a good alternative for short wheelbase tank engines in 7mm scale (MOK's 15XX perhaps?)

 

Impressive build, by the way!

 

Paul

[Simond]

Ok, iteration two of the frames. Firstly, photos of the first attempt.

 

 

And Steph's hornways

 

 

These are drilled, folded up, soldered & tapped in accordance with the instructions. All works as intended, I can recommend these. You'll see the white horizontal pivot plate in the photo above is cut away to avoid these parts. This all gets very cramped, and I'm not convinced that it is worthwhile, so I've decided on a slightly different approach.

 

Unfortunately the photos are not very clear, but I have cut a new set of frames, in which the cutout for the hornguides is 1mm higher. A large horizontal (white) piece now forms the pivot support plate, engages with the hornways, and extends from front to back of the frames. It's not at all prototypical, but it serves several functions, and is entirely invisible, so it's ok in my book. There's a large hole in it to allow the motor be installed from below. I'm not trying to build scale stuff where it serves no purpose, and potentially detracts from the loco performance. The actual functional hornguides will be a pair of separate inner frames milled from 1.2mm brass.

 

The Slaters insulated hornblocks will slide in these inner frames, and I will provide springing using the CSB (continuous springy beam) approach - see CLAG website at http://www.clag.org.uk/beam-annex3.html for more details. This will also serve to retain the hornblocks from dropping out when the loco is lifted.

 

 

 

 

Unfortunately, I didn't quite get my sizes right in the mockup so the wheels are a bit tight on the frames, and don't turn freely, but it will allow me assess the clearances for valve gear.

 

Once I've done that, I can laser cut the templates, and send them for milling.

 

Best

Simon

Edited March 6, 2017 by Simond

[PhilMortimer]

Darn,

 

Those frames look nice and sturdy. I should have held off building mine (all forur of them) and asked you to make some extra sets for me. Oh well.

 

Nice job!

 

I will be getting back to my loco's soon.

 

P

[Giles]

Looks excellent, Simon. Are you going to bring some wiring down through the white plate or does it stay over the Top? (Assuming you're connecting the engines, that is....) I was thinking about mine last night, and was wishing I'd used those miniature magnetic connectors you can get from Micron.

[Simond]

Hi Giles

 

I have some miniature 2 pole JIS connectors, which I will use - the decoders will go in the boiler, I think, and the 2-pole connectors will allow me feed track volts up, and motor volts back down, and to connect the two for analog bogie testing.  The track volts will surely be shared by both decoders, with springing/equalisation and the engines/bogies able to rock, Im hopeful that there will be no pickup issues!

 

The image is the plastic mock-up #2, and I'm still not happy...

 

A number of options present themselves;

 

Plan A was to used milled frames and spacers and Steph's hornguides, Slaters springs and hormblocks.

 

Plan B was to do as above, with a 1.2mm thick inner frame replacing Steph's hornguides, and to use CSB wire suspension - but see below

 

Plan C was to double the inner frames for better support of the hornblocks, but if I do that, CSB suspension won't fit width-ways

 

Actually, the CSB would show below the hornblocks and it won't fit between them and the white plate, so I have to drill the plate and either fit captive springs between the plate and the hornblocks, or CSB above the plate.  CSB above the plate will retain the hornblocks, but it is very tight, so perhaps drilling the plate and tapping the top of the hornblocks and putting a screw through the spring thus capturing both...

 

Alternative D (it hasn't quite made it to a plan) is to make a solid (eg Tufnol) block which contains the rear axle and the vertical pivot for the boiler frames - this can be a rigid hinge on the rear frames and a rocking slot on the front frames - and the leading axle of each bogie supports most the weight of the bogie and the unsprung weight of the motor/gearbox.  Interesting, if simple, machining exercise, and I think it gives the required flexibility for the wheels to stay on the track, combined with simple assembly.

 

In all the above, the intent is to have the cylinders and motion as a separate bolt-on assembly attached to the frames, and the return crank only.

 

Option E - I'm pondering whether this might not be easier if I draw it up and etch it, in which case I can incorporate a lot more features.  Never done any etching...

 

Fallback F - Of course, there is an alternative, to modify the frames supplied in the kit so they work and fit properly, like you and Phil, and the other Phil.  I could revert to Steph's hornguides, which would simplify matters marginally.

 

the Jury will now retire to consider their verdict.

 

best

Simon

[Simond]

Cracking game of rugby...

 

Iteration 73 out of a list of several hundred... I think we have a buildable chassis, with sprung suspension & reasonable appearance

 

Room for the motor & axles to drop out of the horns, all very practical, but it isn't, strictly, a very accurate rendition of the real thing.

 

 

I'm aiming to build another plasticard mockup tomorrow, to convince myself that it will all work.

 

I'm going to try something to do that, I can't cut plasticard with the laser, but I hope I can scan a pattern onto it to accurately mark it out for subsequent cutting in the normal manner.

 

Fingers crossed...

 

Simon

[Giles]

Looks very nice (and practical) To me........ and a damn sight closer to the real thing than the Mercian job!

There is a full depth stretcher in line with the front of the cylinders, which is quite visible and distinctive from certain angles

[Simond]

Thanks Giles,

 

Yes, I knew about that one. I believe it is not in line with the front of the cylinders, but a bit further back, around their vertical mid section, as I have a couple of photos showing steam pipes going into the cylinder block ahead of the said plate. It also has an angle across the bottom edge, which will be challenging for the riveter!

 

In any case, I shall make it from some thinner material, so it doesn't need to be pantographed, as the bits in the CAD will be. It will serve to hide the gearbox from front view shots!

 

I also included the swinging coupling hook. Not sure how well it will work, but it'll look good

 

Right, I've relaid out the parts, and will now scan them onto some 1mm plasticard. Fingers crossed.

 

Best

Simon

[Giles]

Sorry, Simon, your absolutely right - I was going from memory- very careless! The plate lines up with the rear of the cylinders according to the drawings.

 

Can't wait to see the result!

[Simond]

Well, the laser marking of plasticard works very well.

 

It's a fine line between adequately marking and creating a molten mess, but 50 mm/s and 5mA seems ok.

 

 

And another cracking game of rugby...

 

Best

Simon