D869's Workbench Thread

[CF MRC]

On 21/05/2020 at 15:07, 2mm Andy said:

 

I thought it might have been. I remember watching the layout at the Nottingham show a few years ago and noticing the valve gear bobbing up and down as the loco passed me.

 

A chap from Bath by the name of Brian Clarke produced a kit many years ago for a 4mm narrow gauge 'de Winton' vertical boiler loco (one of these) with a split frame chassis that had eccentrics on the acetal plastic axle muff which drove the connecting rods.

 

Andy

Inside valve gear isn’t that big a deal.  It just needs some eccentrics on the muff. The actual straps can be made to clip on. A crank axle needs to be silver soldered for strength. I don’t see any point in doing it unless it is visible or drives the valves on the outside, but a dummy representation is important for all inside cylindered locos. 
 

The loco I am currently working on will have working Joy valve gear, but it is 4mm scale, 8mm gauge. 

Inspired by the recent article in the 2mm mag, I have made it battery powered and my next two locos in 2mm will probably be as well.  Apologies for the thread drift. Beautiful work btw. 
 

Tim

[D869]

8 hours ago, CF MRC said:

The loco I am currently working on will have working Joy valve gear, but it is 4mm scale, 8mm gauge. 

 

Inspired by the recent article in the 2mm mag, I have made it battery powered and my next two locos in 2mm will probably be as well.  Apologies for the thread drift. Beautiful work btw.

Thanks Tim and thanks for the postings about your loco builds which have definitely helped me with the O2.

 

I do like a bit of L&B and am particularly glad that a short stretch has reopened and we can ride in restored coaches and admire the Exmoor scenery. I like my own narrow gauge models in 16mm scale with actual steam though

[Chris Higgs]

5 hours ago, D869 said:

Thanks Tim and thanks for the postings about your loco builds which have definitely helped me with the O2.

 

I do like a bit of L&B and am particularly glad that a short stretch has reopened and we can ride in restored coaches and admire the Exmoor scenery. I like my own narrow gauge models in 16mm scale with actual steam though

 

The problem with the L&B is that with Peco and Heljan weighing in, every man and his dog is modelling it now.

 

Chris

[queensquare]

40 minutes ago, Chris Higgs said:

 

The problem with the L&B is that with Peco and Heljan weighing in, every man and his dog is modelling it now.

 

Chris

 

Not to finescale standards on 8mm gauge track they're not!

 

jerry

[-missy-]

2 minutes ago, queensquare said:

 

Not to finescale standards on 8mm gauge track they're not!

 

jerry

 

Hasn't Alex Duckworth done something similar recently?

 

J.

[2mm Andy]

3 minutes ago, -missy- said:

 

Hasn't Alex Duckworth done something similar recently?

 

J.

 

That was a WW1 military railway, but using 8mm gauge and 2FS standards, yes;

 

Andy

 

 

[queensquare]

20 minutes ago, 2mm Andy said:

 

That was a WW1 military railway, but using 8mm gauge and 2FS standards, yes;

 

Andy

 

 

 

Thanks for the link Andy, I didn't know about those, superb stuff.

 

Jerry

[2mm Andy]

59 minutes ago, queensquare said:

 

Thanks for the link Andy, I didn't know about those, superb stuff.

 

Jerry

 

Agreed, Jerry - they are fantastic models (as is all of Alex's work).

 

Anyway, I expect Andy would like his workbench thread back...

 

Andy

[D869]

3 hours ago, Chris Higgs said:

 

The problem with the L&B is that with Peco and Heljan weighing in, every man and his dog is modelling it now.

 

I reckon if you shift over to a different L&B then you will keep the RTR folks at bay for a while longer

 

https://www.youtube.com/watch?v=ZjBKQlr9fSs

 

The donkey at 1:12 is *NOT* happy!

 

2 hours ago, 2mm Andy said:

 

That was a WW1 military railway, but using 8mm gauge and 2FS standards, yes

 

 

I do like a tin turtle too

 

1 hour ago, 2mm Andy said:

 

Anyway, I expect Andy would like his workbench thread back...

 

 

Oh... don't mind me... the randomness is quite an accurate reflection of the contents of my real workbench anyway.

Edited June 18, 2020 by D869

[Chris Higgs]

22 hours ago, queensquare said:

 

Not to finescale standards on 8mm gauge track they're not!

 

jerry

 

Back in the day, when you had to kitbuild to do the L&B, I produced this. Never got as far as the paint job, or the chassis come to that. Perhaps they came in plain black at some point. It seems I used to be able to solder whitemetal kits, with nothing more than a 12V soldering iron run off an H&M Duette to reduce the temperature. Not sure where that skill disappeared to.

 

If I was tempted to do something 4mm on 8mm track, I think it would be Darjeeling Himalaya. Or perhaps SAR 2' gauge Beyer-Garratts...

 

Chris

 

Edited June 19, 2020 by Chris Higgs

[CF MRC]

I always like to model an area that I know really well and so we have visited Lynton a few times in the last couple of years. It’s preserved railway is delightful. With other foreign prototypes, fascinating though they may be, I would always be doing catch up and making silly mistakes.  
 

I know that the scenery around Lynton is just crying out to be done with a different twist, even though it may be considered the Ashburton of the narrow gauge world.  Equally there should be a big difference in appearance with the 009 commercially available material - as shown by Alex Duckworth’s and, before him,  Paul Holmes’s layouts. 
 

Tim

[D869]

'bout time I put something on here again. I haven't been idle but it would be fair to say that things have rather lacked focus, basically doing what takes my fancy rather than aiming to hit some sort of target like having an O2 running for the DJ Expo. The O2 will still happen though.

 

The last few days are a good example - the Hayle tractor currently has, effectively, 'skid steering'. I want to at least have a try to make the steering work... and consequently redesign the under baseboard drive system... which in turn may have a knock-on effect on the cutouts in the (so far non-existent) baseboard cross members.

 

I did a testbed 'tractor' ages ago with steering working along the lines of the Faller system with one magnet on a 'tiller'. It worked pretty well but what I hadn't realised was that it would only work when the tractor was moving in one direction.

 

One diversion last year was getting the Z axis drive built for my MF70 CNC. This is now working but I'm still learning how best to use it. I decided to put it to the test by using the CNC capability to make a part for the tractor that would be pretty impossible to do manually.

 

This is the new bit fresh off the machine - basically it should hold the steering king pins onto the chassis and provide the pivot for a balanced 'tiller' with a magnet at each end... hopefully without me needing to hack the existing chassis around too much... and without ruling out chickening out if it doesn't work. The alignment was not perfect between the drilling and milling ops, probably because I powered the whole thing down in between. The misalignment is probably about 0.15mm - this is quite an enlarged photo.

 

 

The original steering test tractor fabricated from the usual brass sections without the aid of a milling machine - the big upright king pins work fine but simply won't do appearance-wise. I could have put the rear tyre on straighter too. The tiller was not very robust and has been lost at some point.

 

 

The part finished tractor (old photo) for anyone who hasn't seen it elsewhere on here or at Tutbury in 2019 (seems so long ago... has something happened since then?)

 

 

The Z axis drive on the MF70. At the moment it's using an offcut of laminate flooring for the lower mounting plate. I promise to make a proper aluminium one . It doesn't really draw 3kA.

 

 

 

[D869]

The scattergun approach to modelling activity continues. This time I've been back working on the O2.

 

Before the hiatus I'd left the chassis in bits. I think the final straw was when one of the Simpson springs snapped so the first job was to fit a new one. These are bent into an 'L' and soldered into holes in the frames. The previous one broke at the 'L' bend. This does seem to be a bit of a weakness but space is very tight with the maximum amount of solid metal crammed in so I'll just have to hope that they will be less prone to breakage once I stop messing with the chassis.

 

 

Since restarting I've remembered that the chassis was taken to bits to fit the front guard irons. Again the lack of space was a factor - I milled a recess in the back of the frames to fit the guard irons into. The irons themselves are from the N Brass etch - nice to use a few more bits from it.

 

Putting the chassis back together and refitting to the loco proved that I hadn't finished some jobs before the hiatus because it now didn't fit. A good sesssion of filing was needed to sort out clearances behind the sandboxes but that's sorted now. The chassis has also had a prolonged round of fettling which has improved the running.

 

A pic of the loco in its current state. Progress feels slow and it's a challenge to spot the differences from the previous photo in this photo but there are some... buffers, guard irons, sand boxes, vacuum pipe under the footplate and brake cylinder on t'other side... plus it runs better and goes through pointwork better but you can't see that in the photo.

 

 

Balance weights have now been cut out on the MF70 and await fitting. I've used 5 thou brass, soldered to some scrap etch for milling. This needed more passes than expected because the 5 thou sheet was sitting less flat than expected.

 

[Caley Jim]

22 minutes ago, D869 said:

Before the hiatus I'd left the chassis in bits. I think the final straw was when one of the Simpson springs snapped so the first job was to fit a new one. These are bent into an 'L' and soldered into holes in the frames. The previous one broke at the 'L' bend. This does seem to be a bit of a weakness but space is very tight with the maximum amount of solid metal crammed in so I'll just have to hope that they will be less prone to breakage once I stop messing with the chassis.

P/b wire can be prone to fracturing at sharp bends.  Two tips.  First flick the wire, in the area where you want to make the bend, quickly through a soft flame e.g. a match.  This will slightly anneal it.  DO NOT dwell in the flame for any time as the wire will quickly go soft and useless as a spring.

 

Secondly make the bend gently. Just ease the wire over.  This is less likely to put stress into the bend and so work harden the wire, making it brittle.  After all, you wouldn't like to be made to suddenly change you shape!

 

This second point applies to bending any hard wire.

 

Jim

[D869]

Work on the O2 continues but progress still feels slow. Partly I think it's because I'm now doing fairly small details that don't have a big impact on the whole picture, partly because some of those jobs are the ones I've been putting off and partly for fear of screwing the job up at such a late stage. There seems to be a fair backlog of photos to talk about here so I guess I must be making some progress.  Anyway, here goes...

 

The driving wheels have been off the muffs to have the balance weights epoxied into place. While the wheels were off I also had another go at filing the coupling rods. They are thinner now and I think improved so I decided to stop filing. I may or may not have another round of filing.

 

 

There was no obvious way to attach a coupling to the front so a milling cutter was deployed to turn the previous curvy bottom edge of the spacer into something more amenable and a 12BA fixing hole drilled and tapped...

 

 

Boiler handrails... definitely a job I've been putting off but it could be delayed no longer. I'm using Albion Alloys 0.2mm N/S rod. Step 1 was to use a vee block and progressively smaller drills to form the curve over the smokebox door. I think I ended up around 4.5 to 5mm but the curve radius is not quite so small.

 

 

Then some sharp bends were added either side of the curve to take the handrails out past the corner of the smokebox. After offering up to the boiler, the bends were made to send the handrails back towards the cab. Amazingly I managed to get a decent result at the first attempt. I was definitely not expecting that. The two handrail knobs on the front of the smokebox are soldered to the handrail. The split pins were threaded on and the handrail loosely fitted...

 

 

Then the pins were put one by one into their drilled holes and soldered to the handrail. One hole is nice and deep. The other was pretty shallow so I tried with a 0.3mm drill to make it deeper. No joy... deployed a brand new drill... snap. Finally I remembered that a drill had disintegrated inside the hole when I originally drilled it several months ago so now that handrail knob will have a shorter tail.

 

The two knobs on the sides of the smokebox were unsatisfactory. The right hand one is an odd one out on the real loco, perhaps it is a join. I'd left this as a plain bit of 0.5mm brass rod soldered into the hole in the smokebox but this had no positive way to hold the handrail. I experimented with filing a vee but this wasn't much better. Finally I decided to bite the bullet and try to solder a short length of 0.2mm bore brass tube into the vee. I used another length of handrail rod through the other knobs and coated this with marker pen... the extra thickness of which made it hard to thread back into the tube. After three attempts with Carrs 188 which all came adrift as soon as I tried to remove the handrail rod I resorted to my usual electrical solder and finally managed to get a solid joint without soldering it to the handrail rod. The clack valves also put in a rare appearance during this test assembly...

 

 

The left hand handrail knob is a normal split pin but being in the smokebox had resisted all attempts to solder it into place from inside so it was wobbly. I had several more attempts to get enough heat onto it from inside the boiler before giving up. I decided that the only option was to solder it from outside. After pulling it into alignment with tweezers I applied a fairly generous amount of flux and solder which finally made it stay put... and filled up the hole... and left a messy solder blob...

 

 

Nothing that couldn't be rectified by some careful scraping and a very rare outing for a 0.2mm drill which I am usually far too scared to use.

 

 

Lamp brackets... hmm... I was expecting these to be a nightmare and so far they are proving me right. I'm mostly using the bits from the etch. The six on the rear of the bunker are now in place. Only the top one was at all straightforward. For the middle ones I used some pencil marks and a strip of card to get the two of them at the same height plus some more card to stop the top part welding itself to the bunker. My 25W iron could just about melt the solder but not make a convincing joint. The brackets would at least stay put after that so that I could pin them down with the end of a blade and apply the 80W iron to the bunker rear. It feels odd wielding such a big iron on such tiny parts. That got the joint made but the strip of card was not too happy about it.

 

 

The ones on the buffer beam were the worst, especially the two over the buffers. Several angles of attack and methods of packing were tried before I eventually arrived at the option in the photo - a bit of N/S etch waste wrapped in aluminium foil to prevent it being soldered to the loco. This had the advantage of being able to be held in place by the middle lamp bracket and leaving a bit of room to apply the rather large soldering iron bit to the lower corner of the bunker rear panel.

 

 

Inevitably the brackets are overscale. Sometimes it's better (and MUCH easier) to leave things off rather than doing an overscale rendition but then the bunker rear would look pretty naked. Anyway they are on now and they are staying. The soldering has undone some of my previous solder filling but I think some Milliput will be happening there. Cruel enlargement blah blah...

 

 

Now I've moved on to the front lamp brackets. The buffer beam ones were not too bad after doing the bunker rear. The three that attach to the smokebox front are putting up more of a fight and are still work in progress.

[richbrummitt]

Andy, I think your perseverance is rewarding you. I really dislike soldering brass; finding that it seems difficult to get sufficient heat for the solder to take. Apparently the real problem is getting the brass properly clean enough and I'm told by those more experienced that 12% phosphoric acid flux is the silver bullet. I've also read that Viakal (even neat) is the best option for cleaning up a tarnished etch (and all the brass etches I have stored need a clean) before starting. I haven't tried either yet but thought that you might benefit from trying these ideas.

[D869]

7 hours ago, richbrummitt said:

Andy, I think your perseverance is rewarding you. I really dislike soldering brass; finding that it seems difficult to get sufficient heat for the solder to take. Apparently the real problem is getting the brass properly clean enough and I'm told by those more experienced that 12% phosphoric acid flux is the silver bullet. I've also read that Viakal (even neat) is the best option for cleaning up a tarnished etch (and all the brass etches I have stored need a clean) before starting. I haven't tried either yet but thought that you might benefit from trying these ideas.

 

Cheers Rich. I use Carrs Green Label which I think is phosphoric acid. That seems to do the trick pretty nicely (after a quick rub with the fibreglass brush). I don't think that muck, tarnish or whatever are a big problem for me.

 

The main issue is getting enough heat to where it's wanted as the amount of metal increases - brass conducts heat away much more quickly than N/S. My solution has been to reach for a bigger soldering iron but the bit is not ideal for delicate work.

 

Cleaning for painting is another matter. I've seen it said that tarnished brass provides better paint adhesion than clean brass... not sure if I'm brave enough to try it though.

[D869]

Progress on the O2... basically I have been trying to get the thing from 'nearly finished' to a point where I can stop messing with it. A lot of this has been reworking items which were not completely satisfactory.

 

First to catch up with the final 'new bits'...

 

The front lamp irons went on with a lot less bother than the rear ones. The three around the smokebox were fretted from 10 thou brass because I felt that the fold lines in the etched ones would make them more vulnerable to breaking. Once again the 80W iron was deployed to get heat into the joints quickly.

 

 

The smokebox 'dart' is a piece of 0.8mm brass, cross drilled for the handles and with the rear end turned down to fit into the smokebox door.

 

The final bit of plumbing is a tap on the right hand side of the smokebox. This is pretty small and I was originally planning to leave it off but it's pretty prominent in photos of 30225 so I relented and had a go. My first attempt used 0.8mm brass cross drilled for a 0.5mm spigot. I was quite pleased with it but when I tried it in place it looked huge, so... must try harder. The final version uses 0.5mm brass shaped in the watchmakers lathe and cross drilled for a 0.3mm spigot. A photo of the first and second attempts...

 

 

The boiler is separate from the footplate to facilitate painting etc so the clack valves are tricky to secure. I could have fixed them to the boiler but this would have meant that the upright feed pipe would need to be self supporting. This pipe goes into a hole in the 5 thou thick splasher top so that did not seem like a great idea. Instead I had decided to fix both pipes to the clack and rely on them for location but I'd cut them a bit too short so the clacks could fall off if they tried hard enough. Sorting this was supposed to be one of those 5 minute jobs but removing the original pipes took much longer than I expected - their ends have a shallow taper so that they are a force fit into the holes in the clacks as well as being held in place by solder. Anyway... eventually I got them off and made up longer ones - the horizontal pipes now go right into a hole drilled into the boiler ballast plug and almost meet in the middle of the boiler. The vertical pipes are slightly longer than previously now that I have a better idea of the clearance over the wheel treads. After painting they will get a dab of glue but until then they need to stay put without it.

 

The side tanks have been stuffed with lead sheet. While doing this I found that the front panels of the tanks 'hinged' forwards alarmingly which was definitely not good so those were resoldered... which made the little steps come adrift... so those were resoldered too.

 

On the subject of ballast, my aim since starting this build has been to keep the weight up front and in fact the rear bogie can be removed and the loco will sit on its driving wheels on level track. The first round of lead ballast was kept centered over the rear driving wheels. I can't say that I have ever been fully sold on the 'traditional' view of 0-4-4T weight distribution so it was always my intention to add weight further back and see if things got better or worse. I talked with Laurie Adams and Jerry Clifford on the Saturday Zoom call and they both suggested adding as much weight as possible and springing the bogie to support the rear end. The bogie was already sprung so it was just a matter of adding lead to the rear of the side tanks and then making sure that the spring was strong enough to handle the weight. Having done this I'm now in the 'more weight is better' camp.

 

Running tests have been the other major activity. I've devised a simple shunting test involving two sidings on South Yard. Three wagons are arranged in one siding and the loco must then shunt them in reverse order into the next door siding at a realistic speed and with zero prodding or tapping and dealing with any coupling or uncoupling foibles along the way. Then repeat with the loco the other way around. For a stricter test... add more wagons. Initial tests with the ballasted loco showed periods of good running but interspersed with too many periods of stalling.

 

I've mentioned issues with the Simpson springs losing their 'spring' before and I suspected the same thing was happening again. It was easy enough to unscrew the keeper, drop out the driving wheels and see that the springs were very close to the top of the bearing cutouts and most likely not doing their job very well. The problem is most likely the sharp 90 degree bend where they go through the frames. Jim Watt has suggested annealing with a match but also warned that they can be annealed too much. I preferred to just do away with the sharp bends completely so the new design is a single piece of 36 SWG phosphor bronse wire shich bears on both axles. It's secured into a short length of 0.3mm bore brass tube because I wanted a clear end point for the soldered joint rather than an uncontrolled amount of solder 'creep' between the wire and the chassis frame. It's also easier to locate the tube up against the frame spacer when soldering... with bits of paper and tin foil strategically placed to stop the solder and heat from straying.

 

The old and new versions of the springy bits...

 

 

I think that 36 SWG wire is generally regarded as being too much for Simpson springs and mine may be preventing the axles from sitting at the top of the bearings but the new arrangement can be adjusted with more confidence that it will stay put and the pickup is much improved.

 

I must say that I *really* like the keeper plate chassis design - it allows a lot more flexibility for fettling during the final stages of construction. The cost is some extra complexity in design and finding 10 thou of extra space on each side of the chassis.

Hopefully I can now move on to other things and the O2 can have a period of running trials before I consider throwing any paint at it. Who knows, it may even be allowed out in public at some point?

 

A pic of the loco with its new smokebox appendages in place. Shame I left the clacks and handrails off when i took this one...

 

[Cowley 47521]

That’s a truly inspiring piece of model making. I haven’t really dipped into this section of the forum much before but it’s been very interesting and enjoyable reading through this thread I must say.