Porth Dinllaen in 0

[Kev_Lewis]

I think they're made from the same steel as Slaters' wheels...

 

I don't understand why Slaters can't just make their wheels out of nickel silver?

[Simond]

I don't understand why Slaters can't just make their wheels out of nickel silver?

Cos it don't look like steel, and it costs twice the price of copper!!!

[Simond]

Herewith tender with the top sides lacking only the lamp irons. Need to do the undergubbins and pick-ups.

 

There are steps in the kit but I can't see any on the drawings and photos I have, so have left them off. I think there may be some supports for the handrails which I have not fitted. Rather sketchy info...

 

The other photo is the crud in the bottom of the ultrasonic tank after cleaning up each evening. This is only from the tender!

 

 

 

 

Best

Simon

[Simond]

Herewith tender with the top sides lacking only the lamp irons. Need to do the undergubbins and pick-ups.

 

There are steps in the kit but I can't see any on the drawings and photos I have, so have left them off. I think there may be some supports for the handrails which I have not fitted. Rather sketchy info...

 

The other photo is the crud in the bottom of the ultrasonic tank after cleaning up each evening. This is only from the tender!

 

 

 

 

Best

Simon

[Kev_Lewis]

Cos it don't look like steel, and it costs twice the price of copper!!!

 

Yet we use it for our rails.

[Simond]

You're right, Kev,

 

Martyn (3-link) & I discussed this a while back, we both live quite near the Channel, and the fear of corrosion wrecking hand-made track was a strong argument in out individual choices to use NS rather than steel. It's going to get painted too (except the top) so it's perhaps a bit less critical.

 

I'm not sure it was necessary, it was surely more expensive, and it certainly doesn't look the right colour.

 

Best

Simon

[N15class]

When I lived on the Dorset coast I had little problem corrosion. But here in the rainforest just looking away for a minute is enough for the rust to start, even when blackened.

[Simond]

Peter,

 

When you do the black, do you then oil the wheels?

 

They want to be properly dry, particularly as you'll have just washed the blacking solution off, but then I just wipe on a thin layer of light mineral oil (beard clipper oil is cheap and easy to get, and additive free) and then pretty much wipe it off again. Seems to work, but then your conditions are likely somewhat more severe, more so even than darkest Kent.

 

Best

Simon

[ozzyo]

Hello all, Simon,

 

for your pick-ups on the tender you could use Alan Gibson 4mm ones, you could then fit them in to the drop tank. Using a length of copper clad you can solder all of the pick-up wires to this and then run two wires through the front of the tank to the loco. I have a couple of 4-4-0 Birds to do and I'm thinking along these lines and an idea for pick-ups on the bogies.

 

OzzyO.

[Simond]

Hi Ozzy

 

Thanks for the thought.

 

David (DLOS / Isembard UK) proposed a plunger design that floats, thus minimising the friction loads on the wheels, and I'm thinking along those lines, mounted in the well tank as you suggest. All my tender locos have tender pickups, usually wipers of some sort, though the 28xx has split frames & split axles which works well but is a load more work. I'm pondering getting cast tender wheels rather than using Slaters and then "de-insulating" them.

 

I use PCB pins to make a 2-pole connection to the loco - again tried to standardise so I can plug a power cable into the loco for running in, or fault finding or whatever. I suppose this allows me to mix & match tenders and locos, though I haven't.

 

Best

Simon

Edited December 20, 2016 by Simond

[Donw]

It has occurred to me that as the tender wheels have no power to impart and quartering is irrelevant is should be fairly simple to cut and sleeve the axles making split axle pickup on a tender a good possibility for someone with limited engineering skills (i.e. me)

 

Don 

[Simond]

Don,

 

It is not terribly challenging. The route I took on the 28xx was to drill the axles in two places, maybe 3/4" apart, and to use the fret saw to cut a slot between the holes. This is checked carefully for swarf and then filled with epoxy, and warmed to ensure the epoxy thoroughly wets the sides of, and fills the slot. I wrapped them in sticky tape and left them to set. Job for the thin work gloves, horridly messy.

 

Once set, say 24 hours in a warm place, I cut the from one side of the axle to one hole and from the other to the other. I then checked for swarf again, and checked with a multimeter that all was well. I then filled the remaining slots with epoxy, and left it to set. I then cleaned up, which is quick with a lathe, and only a little slower with a Stanley knife and some abrasive paper.

 

Shorting the wheels is a little more difficult, as you risk melting the spokes. Using a knife edge needle file, I cut a groove in line with a spoke in both hub and rim, applied flux, and with a hot iron, soldered a piece on 0.4mm brass to both hub and rim. Possibly best to do all the hubs, then all the rims, to allow time for cooling. The ensemble can be rubbed on a piece of abrasive on a flat board to remove any lumps & bumps, and the wire epoxied to the spoke if necessary. A dose of black spray will hide all. Obviously using cast iron wheels will avoid this part of the exercise, and add some useful low-down weight.

 

The method for the axles works for quartered wheels too, obviously unnecessary on a tender. Effectively I was practicing in a low-risk environment! What it won't do is work on the axle to which the motor is fitted. I haven't tried this, but there are lathe techniques that are more suited to it.

 

Best

Simon

[Guest Isambarduk]

"David (DLOS / Isambard UK) proposed a plunger design that floats, thus minimising the friction loads on the wheels ..."
 
Indeed, Simon, but others have designed similar: the Sevenscal L&Y pug and all the models from the San Cheng Crafts factory (Bachmann, Tower and FineScaleBrass), for example.
 
If I did write it up on RMWeb, I cannot find it now so, with a bit of cut-and-paste, here it is for anybody who's interested.

This is a photograph of the underside of my GWR Castle but it is the only one that I have that illustrates the device (in front of the red vacuum cylinder).

 

I have reproduced sketches from my ‘model engineers 7mm notebook’, hoping that they will adequately explain the principle:
 

Looking at the ‘scrap view’ at the bottom left, a plastic top hat bush (part 2, shown top right) is retained in the frame by a plastic collar (part 5, shown bottom right); solvent is used to unite the two parts.

A brass solder tag (part 3, shown centre left) is screwed onto a brass plunger (part 1, shown top left) and is followed by a second top hat bush (part 4, shown centre right) that is a clearance fit only on the exposed threaded end of the plunger.

The plunger of the plunger/tag/bush assembly passes through the first top hat bush (part 2) in the frames. A low rate spring passes over, and acts upon, the second top hat bush (part 4) and a similar top hat bush of the opposing pickup assembly on the opposite frame.

This may sound complicated but I find them very easy to make. Because the spring is quite long and low rate it is also easy to make (from a longer spring) as its length is not particularly critical for its correct function, unlike ‘conventional’ plunger pickups.

For the plastic bushes, I use polystyrene but, to prevent melting accidents, I do solder the wires to the solder tags before I insert the plungers in the frames and fit the smaller top hat bushes (part 4).

I have also taken this photograph to illustrate the ‘open-frame-single-spring’ plunger pick ups. I found them difficult to photograph because they are camouflaged black against the black frames and quite a long way in, when seen from below. Here is an early example on the rear wheels of a GWR 3500 gallon tender.
 

I hope that, along with my sketches, this is sufficient to give the idea. As I said, I like that the long, single low-rate spring is not at all critical to set up and that the plunger assembly moves from side to side with the wheels, so the pressure on the plungers remains essentially constant.

I hope this explains things adequately but I am happy to answer questions.

 

David

[Simond]

David

 

Thanks for that, very helpful.

 

It's certainly the case that the spring force will be almost perfectly constant assuming the wheels are true, and that means that a low contact pressure can be used with confidence. I have left the centre axle floating, so won't use that one for pick-up, but the front and rear should be entirely possible, albeit with some minor mods to the design, due to the difficulty of access caused by the well tank (on which the rocking bearing for the front axle is mounted).

 

Season's Greetings!

Simon

[Simond]

 

Not much modelling going on for a day or two, family in residence!

 

Season's Greetings to one and all!

 

Simon

[81A Oldoak]

Not much modelling going on for a day or two, family in residence!

 

Season's Greetings to one and all!

 

Simon

There will be here,  under the cover of entertaining my grandchildren.

[Andrew P]

Merry Christmas Simon, to you and your Family, and have a good 2017

[Jintyman]

All the very best for the festive season to you and yours Simon.

 

Jinty

[Simond]

Happy New Year to all!

 

Pick-ups: per David's drawings above: I made the plungers from the last two inches of 1/16" brass that I had, and turned the bushes (2) from some Tufnol - I started to make the other bushes (4) from knitting needle plastic, but it gets hot & becomes a bit less than useful, so I tried a bit of delrin. This is much better, but the only size I have is about 12mm diameter, and I didn't fancy turning it into swarf, so have given up on the job until I can buy some more suitable material.

 

 

You can see the upper surface of the chassis/well tank which I milled away to get access to the pickups.

 

 

I also cut the front buffers off the stocks and bored the stocks, so I'll solder them on, and fix the upper rear lamp iron which I had put on wrongly. I may fit sprung buffers, one of those round-tuit jobs.

 

 

I also fitted a drag box - strangely not provided in the kit - which locates & fixes the front of the chassis, and I cut away part of the back of the chassis to fit around the coupling. I was going to do this the other way round, as it would have been easier, but the captive nut on the front of the body came off. (Insert smiley of banging head on wall....) So it had to be this way... You can see the hole in the bottom of the drag box, which is tapped 10BA for the drag link pivot.

 

 

It needs vac & steam heat fittings, and the pickups finishing, but we're pretty much there. Loco next!

 

Best

Simon

[Guest Isambarduk]

"but the captive nut on the front of the body came off. (Insert smiley of banging head on wall....) "

 

Here's one for you, Simon:    

 

Ah, yes, the-less-than-captive nut!  It's always seemed to me to be a bit risky to rely on just the area of a nut to solder to so I always solder on a rather larger plate over the hole and then and drill and tap it accordingly.  I can see that there should be no real force trying to shear off the soldered joint but the number of times that I have heard of this happening (and the couple of times that I have been asked to 'sort it, please') makes me think that there must be some resisting torque; could it be solder in the thread of the nut?  Doubt it because I am sure that you would have cleared the thread with a tap before trying to insert the retaining screw?

 

David

[Simond]

Mmm, well, I didn't try to run a tap through it, because when I tried it originally, there was no need. It was only when I was committed and the nut was entirely inaccessible, that it all went pear-shaped.

 

Strangely, I had used solder paste on this, and a few other areas, and some of them also failed. One buffer, one air vent. Don't know if it was a lack of pre-cleaning, or some other reason, but frustrating nonetheless. Anyway, sorted now!

 

And in my spring cleaning (see thread on WT where small ads are free) I found a set of steam heat and vac pipe castings in brass

 

I have no idea if these tenders had a vac tank, there isn't one at the moment, but I feel there probably should be. To investigate.

 

Best

Simon

[Fastdax]

And in my spring cleaning (see thread on WT where small ads are free) I found a set of steam heat and vac pipe castings in brass

 

Hi Simon,

 

Where's this?

 

Duncan

[daifly]

It's here (in the members-only area)

 

Dave

 

You could always join!

Edited January 3, 2017 by daifly

[ozzyo]

Hello Simon,

 

looking at your photo in post #671 showing the intermediate buffers you may have a problem with them!

 

The gap between the loco and tender "buffer beams" should be about 9".

 

Looking at the buffers that your using it looks like the fixed shank will take up all of the 9".

 

I tend to use 4mm LMS buffers with the square base removed for these.

 

OzzyO.

[Simond]

Hi Ozzy,

 

Thanks for the thought. The kit's original castings were very nice, but complete with heads and stocks all-in-one, which obviously wasn't going to work. I sawed the heads off, and popped them in the lathe to drill them through. I haven't given much thought to heads, as, whilst I can turn them, I'm not at all sure it's worthwhile. If they still stick out too far to allow it to follow corners, it won't be a terrible job to shorten them with a file.

 

When I built my 28', I used sprung buffers to supply the current from the tender to the loco buffer plate. For about two days... whereupon I put in a pair of wires and PCB pins per my usual practice. The buffers don't cope well with 1750mm radius track, and given that I use a rigid link to connect the loco & tender, they are not in constant contact. And you pretty much can't see them, so I probably won't bother.

 

However, if you let me know where you source your 4mm ones from, at least I can try them if I think "there's something missing"...

 

Meanwhile, with brakes fitted...

 

 

Best

Simon