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I generally use some strip aluminium from b&q as an interface between work and vice jaws when I think I’m going to be taking the cutter anywhere near the jaws. Apart from saving the jaws you know when you’ve reached the edge of the work because you get different coloured chips (assuming that you’re not machining aluminium of course!) :D

Ian

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The curvy valve cover seemed to go OK - the milled steps gave enough 'purchase' to help me keep a round escapement file straight enough to file the concave curve. The convex curve was done with a whole bunch of different files - flat, half round - whatever would reach the right part of the curve.

 

P1070331.JPG.6cc76425285da0f240b79ec20240e4b9.JPG

 

P1070334.JPG.1a42d1275d3fd5eec28544d72d4f6829.JPG

 

Having this attached proved that I hadn't got room to tilt the boiler enough to clear the (as yet non existent) front lamp brackets. I've re-done the rear supports for the boiler to resolve this. They are now right at the back so the boiler can be tilted more steeply and sooner when it is removed.

 

I've made the handrail knobs (plus spares) but havent done any more on the handrails - it's quite a puzzle to figure out the best order to assemble things. I think I will need to drill a bunch of holes in the cab front to provide support to the back ends of the handrails and boiler top pipework... once I can mark exactly where they need to go.

 

I've been using the watchmaker's lathe to make the remaining twiddly bits to go on the boiler. Once these have all been test assembled, I think it will be time to do a final rub down of the boiler and then attach the boiler fittings, starting with the bigger lumps of metal.

 

The whistle (0.8mm dia) and the manifoldy thing that it sits on... this is a bit of a guess because I don't have great photos showing how this all goes together and the setup seems to vary between locos and over time...

P1070345.JPG.b948808198ae21180a0844b064ee55f0.JPG

 

Clack valves... I hope. From 1mm brass. Drilled 0.4mm for the spigot into the boiler and axially for the feed pipe...

P1070352.JPG.0d6c3106c1119ef559bc8fc7841d69fe.JPG

 

Trial fitting of the whistle, the other boiler top valve (whatever it was for??) with the other big bits plonked into place...

P1070348.JPG.4c748bfad50781c3fb7f7b381c175857.JPG

 

You may have noticed that the handrail holes looked quite big in earlier photos. Thats because they were. I wasn't convinced the 0.3mm drill would cope with the K&S brass tube so I used 0.46mm... which didn't cope that well either. The holes are way too big for the split pin handrail knobs so I've soldered bits of 0.3 x 0.5mm Albion Alloys tube into each hole. We'll see if I can add the handrails without dislodging them too much.

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Andy, prior to trying to drill small holes I tend to “centre drill” them with a sharpened gramophone needle, just a few twists under magnification to make sure the indentation being made is on the cross-hairs I’ve marked. I also use same technique when drilling small holes on the lathe/mill.

I’ve attached a photo of the one I’m currently using. The end is ground to give 3 equal sized/shaped facets which will give 3 cutting edges with a sharp point.

 

Hope that’s helpful

Ian

99E0779A-0135-4ED4-91C9-3277D5A7C5CE.jpeg

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1 hour ago, Ian Smith said:

Andy, prior to trying to drill small holes I tend to “centre drill” them with a sharpened gramophone needle, just a few twists under magnification to make sure the indentation being made is on the cross-hairs I’ve marked. I also use same technique when drilling small holes on the lathe/mill.

I’ve attached a photo of the one I’m currently using. The end is ground to give 3 equal sized/shaped facets which will give 3 cutting edges with a sharp point.

 

Thanks Ian. I think in my case the main problem was with the drill and to some extent my way of driving it. The tube for the boiler was marked out on the lathe and I made an attachment for the toolpost which can take either a centre punch or the shaft for a small drill chuck (cannibalised from an old, broken flexi drive). The punch was turned on the lathe and hardened and that worked very well. The drill not so much for various reasons. I might have been better off just marking out on the lathe and then drilling later on.

 

P1070134.JPG.769bf299a3c8e444ac562a7ccdac5198.JPG

 

I think that the drill bits themselves are also partly to blame - some drills cut really well from new and others hardly at all. I think that getting decent tiny drills is a pretty hit and miss thing. I was using the Titex drills that I bought in 10 packs at Warley a few years back. I have some 0.31mm drills that are absolutely brilliant but the 0.46mm pack seems basically... not great. I wish I'd bought more of the 0.31mm variety but at the time I had no idea if they were good or bad... and it seems the answer was 50:50 between the two packs. These drills do still break. I'm now down to 6 surviving 0.31mm drills so I'm quite cautious about how I use them.

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Drills, especially small ones, are something that’s definitely worth paying a bit more for. Find an industrial supplier if possible that sells to the general public.

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2 hours ago, D869 said:

I think that the drill bits themselves are also partly to blame - some drills cut really well from new and others hardly at all. I think that getting decent tiny drills is a pretty hit and miss thing. I was using the Titex drills that I bought in 10 packs at Warley a few years back. I have some 0.31mm drills that are absolutely brilliant but the 0.46mm pack seems basically... not great. I wish I'd bought more of the 0.31mm variety but at the time I had no idea if they were good or bad... and it seems the answer was 50:50 between the two packs. These drills do still break. I'm now down to 6 surviving 0.31mm drills so I'm quite cautious about how I use them.

 

I have had similar experiences with the Titex drills from Warley. The pack of 0.31mm drills are fantastic - I've only broken one so far, but the 0.28mm size are an absolute b*gger - I broke 3 in one modelling session (trying to drill some nickel silver). Luckily I have far more of the 0.28mm than I do of the 0.31mm size! The same trader still had some when I saw his stand at the Doncaster model engineering exhibition last year, but had sold out of some sizes.

 

Andy

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1 hour ago, 2mm Andy said:

 

I have had similar experiences with the Titex drills from Warley. The pack of 0.31mm drills are fantastic - I've only broken one so far, but the 0.28mm size are an absolute b*gger - I broke 3 in one modelling session (trying to drill some nickel silver). Luckily I have far more of the 0.28mm than I do of the 0.31mm size! The same trader still had some when I saw his stand at the Doncaster model engineering exhibition last year, but had sold out of some sizes.

 

Glad it's not just me. I saw him at the Midlands Model Engineering show last October but I think he just had big stuff on his stand.

 

Regards, Andy

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I finally bit the bullet and soldered the big lumps onto the boiler. I tried Pete Wright's recommendation of using a little blowtorch but didn't get on with this approach - it just got things too hot, too quickly and I was concerned that it was going to unsolder things. I resorted to the big Antex iron and put up with the stray lumps of solder, cleaning these off afterwards.

P1070359-001.JPG.5985d577f8aaf0977c7d10c9d836e625.JPG

 

I also did the smokebox door hinge. I don't have any suitably sized strip so filed down the end of some MSE 18 thou square rod until it was about 8 thou thick. Pete W recommends adding the hinge straps as a pair so that they are in line and parallel before starting. Again the big iron was deployed with a good deal of scraping and fibreglass brushing afterwards. The hinge pin is 0.3mm Albion Alloys brass rod with two tiny bushes of 0.3 x 0.5mm tube at the top and bottom.

P1070356-001.JPG.11953c4b10ff3df60a69fc1e12113a7f.JPGP1070357-001.JPG.f26ef1e8ae587506b530d76f61f274d6.JPG

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I fix my chimneys and domes by first tinning both the boiler where they have to go and their undersides with normal solder.  I then add further generous tinning of lowmelt solder (or some scrap white metal) to the undersides.  The fitting is then positioned on the boiler/smokebox and the soldering iron, set to 300°, applied to the skirt until I see the lowmelt start to appear at the sides.  You have to then hold it there for a few seconds to let things cool down.

 

Jim

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Thanks Jim. I keep considering switching to low melt but there is always something else to go on afterwards so (so far) I keep deciding to stay with my usual electrical solder. To be honest the smokebox door was the only thing that really risked unsticking anything else and that went OK.

 

The big Antex worked quite well - it flows the solder pretty quickly and without fuss and it sets solid pretty quicky because the mass of brass sucks the heat away.

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I use a similar approach to Jim but with 145 solder. I keep going with 188 for a long into the build as possible, switching to 145 at the detailing stage.

 

I like you're dodge with the smokebox hinges, I will be pinching that.

 

Jerry 

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A further update on the O2 build...

 

Before I could fit the cab roof I needed to sort out the fitting of various pipes that pass through the cab front. The first job was to fit the handrail knobs (or 7 out of the eventual 10 anyway) and the extra firebox top valve and pipe that some O2s had so that I could mark the locations for the  holes in the cab. I even used some low melt... on the left hand handrail knob on the smokebox.

 

... and then took the cab front off so that it could be drilled. Not good for the feeling of progress...

P1070363.JPG.d3ff99d1a5f24606431d7c8583d8930f.JPG


Once the cab back together the various twiddly bits in this area could be assembled...

P1070369.JPG.7cb615ba8fea30745e7ae22089097887.JPG

 

Does anybody know what the extra valve and pipe next to the safety valves was for? Some O2s have them and some don't.


Getting the cab roof lined up took some care and a peculiar clamping arrangement to let me adjust it and then solder it...

P1070371.JPG.e658b5ab5672463e9686a0a614d26242.JPG


When it came to the roof ribs I reviewed the various suggestions kindly made by folks earlier in this thread and decided that Jim's way was the most difficult option so I chose that.

 

20 thou was about the thinnest strip of 5 thou brass that I could reliably cut. For the transverse ribs the strips were curved by pulling them between two pairs of pliers over a 3/4 inch bar. It took several round of this to get enough curvature and the strip tended to refuse to stay upright while being curved but eventually I got it done.

 

The first rib was put on without any special clamping arrangements but then I thought of this setup which allowed me to keep the rib in tension while soldering it. Not sure how well it shows up - basically the strip is left long and one end held in the vice.

P1070373.JPG.6a685adaf7417a4274e6b810332492e3.JPG

I think it made the job a little easier but it was never going to be easy. On the plus side, I did find that my 25W iron had just enough heat to do the job... which gave me a lot more control than resorting to the big 80W iron. Then it was more filing and scraping to clean up the stray solder.

 

Once the ribs were on, I cut some 15 thou scrap brass to fit between them and then filed all of the ribs down level with this. 15 thou (plus 10 for the roof itself) is probably a good deal over scale but at least they still look like proper ribs - I was worried that if I filed them down much further they would lose that look.

 

For the final pic today I thought I'd have a break from photos of the O2 under my bench lamp and take it out for some natural light. The BBQ shelf was a handy spot. We've had '2mm in the Garden' on this forum before, so should I rename my thread '2mm on the BBQ' ?

 

P1070378.JPG.6313aebd35fe76ef44a985b8a465ceb8.JPG

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Injectors...

 

My first thought was that these were mounted behind the cab footsteps so a couple of pipes coming out from behind the footsteps would suffice. Looking at photos more closely though told me that I really could see the inector.

 

Pasting a link seems to put the picture in line... hope that is allowed...

30225 - Adams LSWR Class O2 0-4-4T - built 11/1892 by Nine Elms Works as LSWR No.225 - 02/49 to BR No.30225 - 12/62 withdrawn from 71A Eastleigh, where seen 03/63.

 

Looking at more photos just made me quite confused until I looked even more and figured out what I think was the story...

  • Early photos show a horizontal injector type thing mounted under the cab floor ahead of the footsteps. All LSWR and SR era photos on the mainland that I've seen show this arrangement.
  • BR era photos show a different arrangement as on the pic of 30225. It took me a while to find a photo showing a rear 3/4 view but eventually I did. No visible pipework behind the steps.
  • Isle of Wight locos seem to have acquired a different arrangement completely so all of the time spent puzzling over photos of Calbourne was in vain. As far as I can see the IoW do hide the injectors behind the steps and have some interesting loopy pipework.

After trying to get a clearer picture of the injector on an O2 I tried randomly searching for pictures of injectors by different manufacturers. Searching for 'gresham and craven injector' turned this up...

 

Gresham & Craven injector

... which seems pretty much like the ones visible in the O2 photos.

 

Pete Wright's book didn't have a way to make this type so I had to make it up as I went along...

P1070380.JPG.4e764ef02be6e02dbc3efa16f2ade82d.JPG

0.8mm rod, a flat filed on one side, centre punched and drilled 0.4mm. Several attempts may have been needed to get the holes reasonably close to the middle. It's nice that the camera focused on the cutting mat. The 'pipes' were rod that turned out to be 0.45mm so I turned a very shallow taper on the ends which is handy because then they stay put in the holes while the solder is liquid.

 

P1070382.JPG.2364cc4c6bf4df233c3e61cfd645b8f1.JPG

One pipe notched and a short length of the smaller rod notched to fit across it

 

P1070386.JPG.8e162c4a5ef57b41196c2e17a84cf28f.JPG

Soldered up, a twist of 5 thou fuse wire on each pipe and a crankpin washer on the upper one. The O2 photos dont show a big flange on the other pipe.

 

P1070392.JPG.f445051ebafef2b2f7bd68218e3dd7fc.JPG

2 injectors all ready to go on the loco.

 

P1070395.JPG.c10069f4fed3af235233d05f911f91a1.JPG

Injector on the loco. I think you can just about see it. Nice bit of Blu Tack residue on the tank too. Usual words about cruel enlargement blah blah...

 

 

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This is very skilled modelling indeed.  I think that 02 is a little masterpiece. The detail and neat finish is superb.

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Thank you Andy. It has its faults but I'm pleased with it so far... just hoping I can finish it without mucking it up really :)

Hope you are keeping well and keep up the good work with Blueball Summit.

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3 hours ago, D869 said:

Injectors...

 

After trying to get a clearer picture of the injector on an O2 I tried randomly searching for pictures of injectors by different manufacturers. Searching for 'gresham and craven injector' turned this up...

 

Gresham & Craven injector

... which seems pretty much like the ones visible in the O2 photos.

 

Pete Wright's book didn't have a way to make this type so I had to make it up as I went along...

P1070380.JPG.4e764ef02be6e02dbc3efa16f2ade82d.JPG

0.8mm rod, a flat filed on one side, centre punched and drilled 0.4mm. Several attempts may have been needed to get the holes reasonably close to the middle. It's nice that the camera focused on the cutting mat. The 'pipes' were rod that turned out to be 0.45mm so I turned a very shallow taper on the ends which is handy because then they stay put in the holes while the solder is liquid.

 

P1070382.JPG.2364cc4c6bf4df233c3e61cfd645b8f1.JPG

One pipe notched and a short length of the smaller rod notched to fit across it

 

P1070386.JPG.8e162c4a5ef57b41196c2e17a84cf28f.JPG

Soldered up, a twist of 5 thou fuse wire on each pipe and a crankpin washer on the upper one. The O2 photos dont show a big flange on the other pipe.

 

P1070392.JPG.f445051ebafef2b2f7bd68218e3dd7fc.JPG

2 injectors all ready to go on the loco.

 

P1070395.JPG.c10069f4fed3af235233d05f911f91a1.JPG

Injector on the loco. I think you can just about see it. Nice bit of Blu Tack residue on the tank too. Usual words about cruel enlargement blah blah...

 

 

 

Well on the way to Dr Mitchell levels of madness. Keep it up!

 

Simon

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10 minutes ago, 65179 said:

 

Well on the way to Dr Mitchell levels of madness. Keep it up!

 

Simon

 

Well, I do blame him for much of this... him and the late Pete Wright's book anyway. No working inside motion though so I am still somewhat low down on the insanity scale compared to others who have gone before.

 

Thanks Simon.

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10 hours ago, D869 said:

 

Well, I do blame him for much of this... him and the late Pete Wright's book anyway. No working inside motion though so I am still somewhat low down on the insanity scale compared to others who have gone before.

 

Thanks Simon.

 

Great stuff Andy although before you all get too comfortable the next MRJ (no idea at the moment when it will be printed) has an excellent article on making working inside motion with nothing more than hand tools and ingenuity - albeit in 3mm.

 

Jerry

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2 hours ago, queensquare said:

 

Great stuff Andy although before you all get too comfortable the next MRJ (no idea at the moment when it will be printed) has an excellent article on making working inside motion with nothing more than hand tools and ingenuity - albeit in 3mm.

 

Jerry

 

Would that be Irish 3mm scale working valve gear by any chance, Jerry?

 

Andy

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1 hour ago, 2mm Andy said:

 

Would that be Irish 3mm scale working valve gear by any chance, Jerry?

 

Andy

 

Might be :D

Seriously, its very doable, even for mere mortals. Just need to figure out how to do it with split axles and muffs.

3D printed crank axle muff?

 

Jerry

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14 hours ago, D869 said:

Well, I do blame him for much of this...

Makes a refreshing change from the sorts of things I usually get blamed for!

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5 minutes ago, queensquare said:

3D printed crank axle muff?

 

Funnily enough, I had been thinking about this recently, inspired by John Birkett-Smith's article in the October 1985 Magazine.

 

Lots of L&Y locos had Joy valve gear, and in some instances bits of it projected above the level of the footplate.

This isn't my video, but you can clearly see ends of the rods which connect to the valve spindles bobbing up and down between the top of frames and the bottom of the boiler.

 

 

 

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56 minutes ago, queensquare said:

 

Might be :D

Seriously, its very doable, even for mere mortals. Just need to figure out how to do it with split axles and muffs.

3D printed crank axle muff?

 

Jerry

 

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

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Stewart Hine made his 28xx with eccentrics on the muffs. I had the opportunity for him to explain how he did this at a Keen House meeting. There's was an article in the magazine about it too I believe.

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Posted (edited)

Brakes...

 

I knew this was going to be quite an involved job and sure enough it was... and so is this post (sorry!)

 

The O2 brakes are pretty prominent and even the cranks by which they are driven are on full display. MinerChris does have one of Mr Higgs' chassis etches in his gloat box so I could have pinched the brake etches from that but that seemed rather a waste.

 

The Dave Holland keeper plate design complicates matters because the brakes must be removeable if the wheels are also to be removeable. I spent a whole evening just thinking about how to make all of this fit together. The eventual design is pretty similar to the one recommended in Pete Wright's book but I did consider two alternatives before arriving at this. The key 'lightbulb moment' was the idea to solder short lengths of 0.5 x 0.3mm tube into the brake hanger pivot holes in the frames. This gives just over 1mm of length for location and support rather than relying on just the 0.5mm thickness of the frames.

 

Spoiler alert... the finished article

P1070440.JPG.dc4f18d39c1f57ce9269237171ed8ee4.JPG

 

Before starting on the real thing I made a fairly basic test piece to find out if it was actually possible to solder this thing together and also to see if the hangers could be poked up behind the coupling rods when assembing the chassis. This was a very useful exercise, apart from proving that I could put the thing together it also showed me that I needed to make the hangers longer by 0.5mm to avoid the pull rods fouling the coupling rod bosses at bottom dead centre.

P1070437.JPG.3d6fe61f243a0fc0edc47b55b1617d55.JPG

 

The pull rods are 0.4mm MSE point rodding strip. Height-wise this is pretty much spot on with the GA drawing but no doubt the real things were not square in profile. They are also nice and strong. A couple of pieces were soldered with some temporary plain rail spacers at the correct spacing. The cross pieces are 36SWG phosphor bronze bent into an 'L' and soldered behind the pull rods.

P1070409.JPG.806206e152b002f0a2d8d12d8c7f046b.JPG

 

For the hangers I made a drilling jig using the MF70 to get the hole spacing correct and then drilled some 1mm wide scrap etch and filed it to the general outline. 36SWG wire was soldered in for the top pivots.

 

Having taken a break from CNC for the hangers I decided that manual filing was overrated and went back to CNC for the other bits. Because of the tiny parts involved the blank was soldered to a backing plate rather than relying on sticky tape. One of them still came unstuck though (lack of solder coverage).

P1070405.JPG.73dff48ad4f4e6e1ba6aaee64272e8c3.JPG

 

An O2 brakes kit...

P1070406.JPG.658be1ba61e132d2defb5eb28b34de94.JPG

 

Soldering the shoes onto the hangers involved a bit of trial and error and some swapping things around on the final assembly to find the best combination.

P1070412.JPG.b9b218bc293af1cfd331f5788dd3fd72.JPG

 

The assembly was then fitted to the chassis and the hangers soldered to fix them to the cross shafts. Some aluminium hairgrips were used as heatsinks to prevent the cross shafts coming unstuck from the pull rods.

P1070414.JPG.7e2f18270fcf5da29cab21b9e11dc72a.JPG

 

Some small bits of 0.4mm PCB were gapped and used to join the cross pieces in the middle. The temporary spacers could then be removed.

 

Which just left the connections to the cranks to sort out. On the real thing these have an adjuster so I wanted to represent that. I used some bits of 5 thou N/S strip that I bought very cheaply many years ago and am now running out of. This was bent around a drill and 0.4mm brass wire soldered into the 'U' for the 'pin' into the crank. In fact this is just soldered to the face of the crank rather than being pinned.

P1070426.JPG.8bc262405392b0f90e1eb45878499722.JPG

 

Once cut to length the adjuster will quite happily grip the pull rod, can be adjusted to line up with the crank and will stay put while being attacked with a hot soldering iron. Nice :) . The photo was taken before soldering.
P1070435.JPG.3c8265d724bf6cd1cc0eea68595672c8.JPG

 

I got a bit silly with the bosses at the ends of the cross pieces. These are 0.8mm brass rod with a the end filed down to leave just a 0.2mm thick sliver to sit on top of the pull rod. A 0.5mm-ish disc (plus the 'sliver') was parted off in the watchmaker's lathe and the resulting bit soldered onto the pull rod (heat sink deployed again). I think I must have made at least 8 and failed to file the 'sliver' several more times. Once attached to the pull rods, the bosses were filed back to about 5 thou thickness.

 

Once all was assembled the loco was taken for a test run through South Yard's 'interesting' radius pointwork. It made it through but there was some 'rock and roll' due to a clearance issue. Can you spot it?

P1070443.JPG.73743eb766f145b42d133fb8b1c9563f.JPG

 

 

Edited by D869
spurious extra pic
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