7mm scale Manning Wardle Old Class i: a self-designed 'kit'

[doilum]

Which explains why Slaters chose a 1/8th axle for the K .

[jdb82]

3 hours ago, doilum said:

Which explains why Slaters chose a 1/8th axle for the K .

 

Yep. I'll see how I get on with things......version 2 might see a bit of a redesign based around the smaller axels.

[doilum]

21 minutes ago, jdb82 said:

 

Yep. I'll see how I get on with things......version 2 might see a bit of a redesign based around the smaller axels.

Hope so. The rest of the kit deserves it. I took 25 years of on/ off progress to finally finish the K.

One crazy idea might be to cut the 3/16 axle in two, turn down the cut ends to 1/8 and rejoin with epoxy around the above mentioned gear set. It would of course require an open horn block arrangement to refit the axle.

Edited October 14, 2021 by doilum

[jdb82]

4 hours ago, doilum said:

Hope so. The rest of the kit deserves it. I took 25 years of on/ off progress to finally finish the K.

One crazy idea might be to cut the 3/16 axle in two, turn down the cut ends to 1/8 and rejoin with epoxy around the above mentioned gear set. It would of course require an open horn block arrangement to refit the axle.

 

If only I had a lathe....... 

[jdb82]

Date night with the firebox & back head. There's pipework and a couple of other details that will be added after painting. 

 

 

 

 

 

[Timber]

that really looks good

[jdb82]

Any tips on bending half round brass wire laterally through a 2.5mm radius, 90 degree bend? Is it just a case of annealing it? Whenever I try, it just ends up bending round the flat side.....

[doilum]

17 hours ago, jdb82 said:

Any tips on bending half round brass wire laterally through a 2.5mm radius, 90 degree bend? Is it just a case of annealing it? Whenever I try, it just ends up bending round the flat side.....

Cheat. A few strokes with a piercing saw on the inside of the intended bend will help. Once in shape, a little solder will make the bodge invisible after some careful filing.

[jdb82]

Having discussed different methods on various platforms to forma lateral curve in half-round beading above, here's a quick comparison. The first image of the right hand side was formed by soldering 2 pieces of beading back to back to make a round wire. The curve was formed around a drill bit of suitable size, and the 2 pieces were separated, and soldered to the cab side. 
In the second photo of the left hand side, I soldered the beading on whilst the cab side was in the flat, and then formed the curve. Whilst the net result is very similar, the second method I found considerably less fiddly, and much easier to clean up.

 

[doilum]

Every day a school day!

[Portchullin Tatty]

As small point, an possibly less of an issue in 7mm in comparison to 4mm.

 

I find that nuts sometimes break loose because the surface area soldered is not that large.  If the nut is hidden away (as per the nut in the bunker in the last view), it becomes impossible to do anything about it. 

 

I thus wrap a little bit of wire around the nut and then solder this in place too.

[jdb82]

20 minutes ago, Portchullin Tatty said:

As small point, an possibly less of an issue in 7mm in comparison to 4mm.

 

I find that nuts sometimes break loose because the surface area soldered is not that large.  If the nut is hidden away (as per the nut in the bunker in the last view), it becomes impossible to do anything about it. 

 

I thus wrap a little bit of wire around the nut and then solder this in place too.

 

The wire is a good idea - I hadn't thought of that. It's not too late to add it. Hopefully there won't be a problem - as long as the screws aren't overtightened!

[jdb82]

Straight forwards construction of the smokebox, with a front, rear and base (with fixing nuts for attaching to the running plate), with a riveted wrapper around the outside. The castings for the smokebox door and chimney are solid, and so unusually for me, I decided to epoxy these in place rather than solder, as I feared the heat needed would make everything fall apart. The flare on the chimney needed a bit of altering - I'll do this on the CAD file before I get another set cast. It's still not perfect now, and will need a bit of filling.

 

 

 

And just staged for a quick photo to show the state of play so far. The boiler is a length of nickel silver tube.

 

 

 

Tank next......

[doilum]

On 29/10/2021 at 12:13, Portchullin Tatty said:

As small point, an possibly less of an issue in 7mm in comparison to 4mm.

 

I find that nuts sometimes break loose because the surface area soldered is not that large.  If the nut is hidden away (as per the nut in the bunker in the last view), it becomes impossible to do anything about it. 

 

I thus wrap a little bit of wire around the nut and then solder this in place too.

Brass nuts take solder better. Clean with the Dremel leaving a rough surface. Apply flux and carefully paint the screw thread with WD,40. Tighten down and then apply heat and solder. Check that the screw still turns and remove. Any surplus solder can be ground back with the Dremel. Don't forget to clean off all the flux.

Whilst we all strive to produce the neatest joint with the minimum of solder these nuts by their nature will be hidden and probably inaccessible should the solder fail.

[jdb82]

57 minutes ago, doilum said:

Brass nuts take solder better. Clean with the Dremel leaving a rough surface. Apply flux and carefully paint the screw thread with WD,40. Tighten down and then apply heat and solder. Check that the screw still turns and remove. Any surplus solder can be ground back with the Dremel. Don't forget to clean off all the flux.

Whilst we all strive to produce the neatest joint with the minimum of solder these nuts by their nature will be hidden and probably inaccessible should the solder fail.

 

These are brass nuts, and as you say, because they will be hidden I have used plenty of solder. I reckon they'll last for a while.

[jdb82]

Here's the tank completed, ready for soldering to the boiler. I've added the handrail knobs and the injector fittings. On second thoughts, I'm not sure if it's an injector per-se, or if it's just a pipe junction into the tank. It is just a single pipe out of the tank, and I'm not sure if the early old class i's (which this is) had injectors or not. I just (blindly) followed the drawing! Answers on a postcard, and apologies for my lack of loco anatomy knowledge.....

 

Whilst the tank filler seems to be correct when compared to the drawing I have, I think it looks too bulky/tall in comparison to the tank itself. I may well (try and) remove it and 3D print a replacement. So if anyone knows how to remove Devcon  2 ton epoxy (yes I know.....belt & braces etc.) without completely wrecking the thing, then let me know ;-)

[Marshall5]

The pipe fitting on your tank is likely to be the water feed to the injector or crosshead driven feed pump with which, IIRC, some MW's were fitted.  Thoroughly enjoying following your build.

Ray.

[jdb82]

11 minutes ago, Marshall5 said:

The pipe fitting on your tank is likely to be the water feed to the injector or crosshead driven feed pump with which, IIRC, some MW's were fitted.  Thoroughly enjoying following your build.

Ray.

 

Thanks for that Ray. I think it must be to to the crosshead driven pump then, as I can't see anything injector like on the drawing. The pipe disappears down between the frames somewhere, so seems likely :-)

[doilum]

I might print the replacement before attacking the original which doesn't look that bad. With electrician's tape to protect the surface you might try a cheese wire approach with a piercing saw blade.

[Ruston]

The tank looks very good, but the filler is definitely too tall. Epoxy type adhesives break down if left to soak in Nitromors. If you have soldered the rest of the tank together, just leave the thing immersed in Nitromors for a day or two and the lid will fall off. It's worked for me with whitemetal kits.

[jdb82]

2 hours ago, Ruston said:

The tank looks very good, but the filler is definitely too tall. Epoxy type adhesives break down if left to soak in Nitromors. If you have soldered the rest of the tank together, just leave the thing immersed in Nitromors for a day or two and the lid will fall off. It's worked for me with whitemetal kits.

 

I should get myself a tin......Although in my haste, I have since soldered the tank to the boiler, making that somewhat harder  I had been thinking of cutting under the top overhang, grinding down the central section to a more suitable height and then reattaching the top portion. 

There's also a part of me that say that this is just a test build - it could stay as is for this particular build and be altered easily for future versions, however the traditionalist in me might not allow that to happen!

[doilum]

I did resist the temptation to suggest the angle grinder! 

Any use of grinders, great or small needs to take account of heat and collateral damage. It is too easy to damage an otherwise superb tank. It might mbe worth gluing a pound coin or similar to some scrap brass with the Devcon and then testing the chemical approach.

[37Oban]

Just an idea, and I've no idea if this would work, place the unit into a sink of ice cold water up to just above the top rivets and, with care, gently play a flame from a gas torch around the joint to heat and soften the epoxy  then gently wriggle the filler free.

 

Roja

[jdb82]

Thanks for all the suggestions - I'll have a play around with a few methods with some scrap :-)

[Timber]

Lovely work.   I will be interested to see where the leaf springs attach.  On the original etch it looked like they were to be folded up.  Are you going to do something different now in construction.

 

The model looks lovely - enjoying the read,