Etching concepts, and modelling! - random bits & bobs which don't have their own topic

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PeteT
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Re: Etching concepts... and modelling!

Postby PeteT » Wed Nov 21, 2018 9:04 pm

Seeing as I havent updated this topic for a while, I thought I'd throw a couple of things at it (I have fitted in a good amount of modelling time this year, but tried to keep up with progress rather than documenting it... always a difficult balance!:

First off, almost ready for the chassis to enter the paint shop, is a Rumney Models B32 9' wheelbase Morton under a Cambrian kit for an LMS D1832A wagon. Axleboxes are from the Rumney stable too, FH05, with buffers from Lanarkshire B006.

I used DCC concepts 100 degree solder for the first time on this build, for the fitting of whitemetal castings - not only did it remove the faff of tinning the brass first, but the flow and joint is much more like normal solder than low melt ever manages, so I'm very pleased with it.

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Secondly, the first two pieces of a Skytrex Midland water column. The instructions are a little vague but the parts are nicely done and alongside the article on such columns in the Midland Record Preview edition I'm sure I'll work it out!

20181121_194555.jpg

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PeteT
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Re: Etching concepts... and modelling!

Postby PeteT » Thu Nov 22, 2018 5:21 pm

Just to add, following a question at this weeks BS4 gathering which may be of wider interest: For the 100 degree solder I just used my standard flux, which is a blue liquid from 7mm Locomotives:

http://www.7mmlocomotives.co.uk//index. ... &Itemid=52

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PeteT
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Re: Etching concepts... and modelling!

Postby PeteT » Sun Jan 27, 2019 6:30 pm

In amongst Ilkley and 1P bits, the Ivatt 2 tank has come back into the active projects queue. It had stalled for 2 reasons - crossheads and swinglink pony bits. Both of these have now been resolved.

Dave Holt was kind enough, at S4N several years ago, to share with me his sketch for the parts he created to modify the Brassmasters pony truck. In December I finally got round to finishing drawing up an etch. This should be with me early next month (alongside some coal rails for the 1P).

The crosshead - having discounted the Comet and Markits versions as not looking close enough to the prototype - I was also going to draw up and etch as a series of laminates. This I had parked while considering how to mate the flat etches with some tube/rod for the piston rod. In the meantime I had a look at the DJH option used in their Standard 2 tank kit, and was actually very impressed with it, so am now using that. The Comet slide bars needed quite a bit of fettling to make them work together, but in my opinion has been worth the effort.

The crosshead pin hole is rather large in the DJH casting, but using some 1.2/0.6mm tube sorted that out and looks like the prototype assembly too. The rest of the valvegear has been assembled as per the Comet instructions, aside from 2 parts. Firstly, the instructions say to put the combination lever outside the union link, which in the prototype is the other way around. Doing this properly may result in clearance issues, time will tell! Secondly, the expansion link is supposed to be assembled just with wire, but I couldn't get all the parts inserted alongside 2 bits of fag paper - so instead this uses a lace making pin from the inside (lace making pins used throughout in place of the Comet rivets).

Apologies for the quality of some of the photos - the lighting wasn't perfect, and these are several times real size! But hopefully show the point.

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steamraiser
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Re: Etching concepts... and modelling!

Postby steamraiser » Sun Jan 27, 2019 7:01 pm

Nice workmanship Pete.

Gordon A

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PeteT
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Re: Etching concepts, and modelling! - currently 1P and Ivatt class 2...

Postby PeteT » Mon Jan 28, 2019 8:50 pm

Thanks Gordon :)

The valvegear is now fully assembled, just about clears the leading crankpin, and is waiting for an M1 tap to arrive for use on the return crank. It doesn't stall the project though, as there is the brakegear to sort out, and the fitting and sorting clearance for the sprung side controlled (rear) pony tuck.

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The next deficiency is now apparent - the cylinder wrapper casting. It is quite rough, which I can deal with (and might yet fully sort out at the expense of the rivets, which can be replaced with Archers) - but also lacks the circular cover, which I think is the valve chest cover. Thankfully (if I'm right of course...) these are available from Brassmasters (part A059).

I also don't like the look of the etched attachment behind the rear valve chest (in front of the valve rod). Brassmasters appear to do a casting for this, but I can't see it listed separately (though it might help if I could name it!).

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Mike Garwood
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Re: Etching concepts, and modelling! - currently 1P and Ivatt class 2...

Postby Mike Garwood » Mon Jan 28, 2019 9:21 pm

Pete
Nice work, I think that rough patch on the cylinder cover will rub out with a 5mm scratch pencil. Might save you a job or two.

regards

Mike

Dave Holt
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Re: Etching concepts, and modelling! - currently 1P and Ivatt class 2...

Postby Dave Holt » Tue Jan 29, 2019 11:30 am

The Ivatt 2 looks to be coming along nicely, if possibly even slower than mine!
I think I used the Comet etched valve guides and if I remember correctly, I might have slightly shortened the cast white metal valve chests. Mind you, it's so long since I did that part of the construction, I wouldn't be absolutely certain. Comparison with drawings or photos is probably a better guide.
Here's a (slightly out of focus) photo of my version with the cranks set in roughly the same position. I also used the Comet cross heads but with the cast spindles replaced with N/S wire (see also my second response to your comment on my BR Std 2 thread). I also replaced the cylinder wrappers with sheet brass, having reduced the front and rear formers to replicate the earlier, smaller bore cylinders fitted to the first batches of these locos (I used the Comet cast versions on the BR Standard 2 tank, as these had the later, larger cylinders). The circular covers, with etched bolt heads, were in the Comet chassis pack, I'm sure.

Ivatt_2T_002.JPG


Good luck with the rest of it.

Dave.

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PeteT
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Re: Etching concepts, and modelling! - currently 1P and Ivatt class 2...

Postby PeteT » Tue Jan 29, 2019 7:57 pm

Hi Dave,

Thanks for your replies. Yes, this one has been on and off the burner for quite a long time! I have generally been better in the last 2 years at being less scattergun with my modelling time, and it has seen good results. Hopefully the Ivatt will follow the theme within this year...

I have had another look at both the bits in this project, and a fresh (albeit old style) Comet kit for the 2-6-0 and neither have the cylinder circular cover (not does the photo on the old Comet website. The tender loco kit has 2 unpainted photos which don't show it, and 1 painted photo which does but could well be an addition by the builder). But I am pretty sure that is what Brassmasters have it as an extra, and if not shouldnt be hard to make/draw up.

Interesting that you chose to represent the smaller cylinders - isnt the difference 1/2"? Or is that in the cylinder/piston dimension, and more pronounced on the outer casing? If there is a visible difference I would like to represent it (I have plans for 41273 (this one), 41325 (later Ivatt batch) and 84009 (or 84015) sometime this century so making sure all the differences between the 3 are covered is something I'm keen to do). There may also be 41284, none PP fitted unlike all the others mentioned, and Ilkley based, to add too. Crumbs!

Another neat idea I've noticed on your standard 2 topic is the casting behind the lifting arms/expansion link which you've anchored onto the motion bracket assembly, which looks a good way of doing it.

I think the shape of the Comet crossheads looks fine as you say, it was more the droplink attachment detail and to a certain extent the hole in the top. I'm sure it will come back to bite me, and won't be noticable once painted and weathered, but all part of the fun!

Mike - thanks for tha idea too, sounds a sensible approach!

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johndarch
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Re: Etching concepts, and modelling! - currently 1P and Ivatt class 2...

Postby johndarch » Wed Jan 30, 2019 5:28 pm

Did you sort out your problem with the tender wheel sets. There was a problem with the Exactoscale bearings as they were not properly coned in as much that they did not come to a point. I use Alan Gibson bearings with Exactoscale wheels and they work fine. Some of the older ones were a bit hit and miss and I probably only used half of them but quality control seems a lot better these days.

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PeteT
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Re: Etching concepts, and modelling! - currently 1P and Ivatt class 2...

Postby PeteT » Wed Jan 30, 2019 9:58 pm

Thanks John. The J39 hasn't been progressed, but is next in the queue to recomence so hopefully will see the light of day this year!

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PeteT
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Re: Etching concepts, and modelling! - random bits & bobs which don't have their own topic

Postby PeteT » Fri Apr 10, 2020 4:50 pm

One thing I did today was add some bufferheads to some LMS (Lanarkshire) buffers affixed to Rumney BR 16T mineral underframes.

I do this with a piece of 20 thou plasticard with a slot in it for the shank, which holds it at about the right extended length, at which point the tail can be bent. Nothing particularly exciting or new - but keeps them uniform, stops them being dragged in while forming the bend. A quick and painless process.

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I'm not saying this is a ground braking jig, but thought it may be of interest.

Also, following discussions elsewhere, sheet lead is stuck with epoxy. Covering the underside of the floor brings it to slightly over 40g.

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Andy W
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Re: Etching concepts, and modelling! - random bits & bobs which don't have their own topic

Postby Andy W » Fri Apr 10, 2020 7:11 pm

The jig’s a good idea. I don’t bend the tails anymore but slide short lengths of plastic insulation stripped from cable to fit tightly. The heads can then be removed if needed.
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PeteT
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Re: Etching concepts, and modelling! - random bits & bobs which don't have their own topic

Postby PeteT » Fri Apr 10, 2020 8:14 pm

Ah, thanks Andy! I was thinking as I did them that there is a chance they could snag later, and knew I had heard of a better way - but couldn't remember what it was! I've put some wire in with the buffer heads as a reminder for the next one :)

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Noel
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Re: Etching concepts, and modelling! - random bits & bobs which don't have their own topic

Postby Noel » Sat Apr 11, 2020 10:50 am

PeteT wrote:I do this with a piece of 20 thou plasticard with a slot in it for the shank, which holds it at about the right extended length, at which point the tail can be bent.


I do the same thing, with a rather thicker bit of plasticard [is your bit of plasticard really 20 thou, Pete? It looks thicker in the photo, and 20thou doesn't give much travel]. I don't put the heads in until the rest of the work on the wagon is finished, including all painting, and have not found any need to remove the head [yet!]. I make the bend with a screwdriver blade against the back of the headstock, if I've drilled out plastic kit buffers [quite possible with care], or the buffer casting, and then carefully trim the tails with an end cutter, close to the bend.
Regards
Noel

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PeteT
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Re: Etching concepts, and modelling! - random bits & bobs which don't have their own topic

Postby PeteT » Sat Apr 11, 2020 11:55 am

Good point Noel - I think when I made it I was just rumaging around the offcuts box to find a bit which brought the head to 1'6" from the headstock. I will measure it for clarity.

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David B
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Re: Etching concepts, and modelling! - random bits & bobs which don't have their own topic

Postby David B » Sat Apr 11, 2020 1:16 pm

I made a similar jig out of brass and put a grip on to it - bit of tubing, slit and held on with araldite.

The other item is a depth gauge I use when drilling out white metal buffer stocks. The narrow bit is 1mm rod which is 5mm long, the length required to accommodate the buffer and compressed spring when the buffer is pushed in. Beyond the 1mm hole, I drill the rest of the way 0.5mm to take the tail of the buffer. I put a piece of 1mm x 0.5 tube over the drill to keep it centred in the hole.

Buffer-jig_3672.jpg

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PeteT
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Re: Etching concepts, and modelling! - random bits & bobs which don't have their own topic

Postby PeteT » Sat Apr 11, 2020 4:11 pm

Thanks David. Yes that depth gauge, and drilling sleeve, do sound useful! I haven't drilled any myself, mainly due to working out how to start that first 1mm hole. No doubt the 'proper' way to do it involves a lathe to nicely hold the buffer shank and the drill bit and from there it is easy peasy...

I've always assumed drilling from the 'front', but a similar sleeve arangement to fit over the rear shank (which for a given manufacturers range is presumably the same regardless of buffer type and size) and drill through from there may work? That would mean starting with 0.5mm and opening out to 1mm, which itself would need care to prevent wandering - so probably creates as many problems as it solves.

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Wizard of the Moor
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Re: Etching concepts, and modelling! - random bits & bobs which don't have their own topic

Postby Wizard of the Moor » Sat Apr 11, 2020 8:42 pm

Drilling on a lathe only works if the rear spigot and buffer shank are concentric. This depends very much on the manufacturer, but can't always be assumed. Guess how I know... :(

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David B
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Re: Etching concepts, and modelling! - random bits & bobs which don't have their own topic

Postby David B » Sat Apr 11, 2020 9:11 pm

I chop off the white metal buffer head and stem, file flat and mark the centre by eye with a scribe. Holding by the tail in a lathe can be tricky because, as James says, it is not always central and I have known the twist of the drill to snap it. Quite often I end up holding the buffer vertically in a vice, one with a notch in the middle of the jaws. Holding the buffer is the difficult bit, not the drilling.

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Will L
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Re: Etching concepts, and modelling! - random bits & bobs which don't have their own topic

Postby Will L » Sun Apr 12, 2020 12:54 am

David B wrote:I chop off the white metal buffer head and stem, file flat and mark the centre by eye with a scribe.


This does not need to be a precision job so I start like that too, the most critical thing is marking that Center point with reasonable accuracy, but by eye is quite good enough. Once that's done, I think for several reasons it is much preferable to start by drilling 0.5mm all the way though.
1. a 0.5mm drill goes though a lot easier than a bigger drill, and
2. the 1mm drill will follow the 0.5mm hole without any drilling aid being necessary.
I do it all by hand, by eye, white metal cast buffers I just hold in my fingers. I've never failed to get the 0.5 drill near enough down the centre of the casting. It doesn't mater if its visibly off centre by the time it comes out the back, so long as your not so far off line as to break out the side of the casting. As I said I've never missed yet. Then open out the 0.5mm hole to 1mm to sufficient depth that a buffer head will just touch the shank with the spring fully compressed. (Ok 5mm if you must measure but the job is easily done without any aids at all).

I also use a small section of insulation off a thin wire to hold the buffer in now. To start with I did that as a temporary measure so I could disassemble for painting, but it worked so well the temporary became permanent.

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PeteT
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Re: Etching concepts, and modelling! - random bits & bobs which don't have their own topic

Postby PeteT » Sun Apr 12, 2020 8:09 am

Thanks for the thoughts - I do have some solid ones in stock so will have a go at some stage.

Part of the love/hate relationship with this hobby is the variety of things to do and skills to collect - great in terms of having that variety of tasks and achievements, but bad in terms of the need to master so many before things hit 'finished' status! so as least for things like this there are workarounds to buy for the first sets.


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