Modelling of A3 / A4 tender details

[Dog Star]

Building a Finney kit for the LNER 8 wheel tender as running with the A3 and A4 classes... and a couple of questions have arisen - I hope that one or two WTers may be able to help.

[1] the operating rod for the water scoop operating mechanism is on the centre line of the tender where the rod joins the cross-shaft under the front drag box, the rod is off of the centre line where the rod attaches to the lever / cross-shaft above the movable portion of the scoop.  Where does the rod change alignment?

[Any one have a LNER dwg of this type of tender?]

[2] there are vacuum bags at each end of the tender...  similar for the steam heat connections...  there are two water bags at the front of the tender.  What might WTers suggest as being a suitable means of representing these flexible pipes?

thank you, Graham

 

[Rob Pulham]

H Graham, are you wanting them to be flexible or just appear so?
I have an Isinglass drawing of the Streamlined tender (along with the A3) but it doesn't show the detail that you are looking for for the scoop operating mechanism so not any good I am afraid.

 

[Dog Star]

...  are you wanting them to be flexible or just appear so?

Hi Robin,

Our preference is for the model flexible to be flexible....  that is just a preference.  Thank you for checking the Isinglass drawing, another dead end.

regards, Graham

 

[Rob Pulham]

I was going to suggest guitar strings but they wouldn't be flexible. but would some heat shrink tube over a suitable spring give you the effect you are looking for while still being flexible - I have a few different diameters of heat shrink if you want some to test?

 

[Dog Star]

... would some heat shrink tube over a suitable spring give you the effect you are looking for while still being flexible...  ?

I like your thinking Robin and I know a man who has a range of heat shrink tubing....  the spring might be a bigger problem.

Richard has a very nice arrangement to the rear of the tender for Diamond Jubilee and I am hoping that details will be forthcoming.

regards, Graham

 

[Dikitriki]

Eh?
Have I?
I'll have a look later.
I suspect I used silicon tubing which I ran first through a suitable die to provide the 'threads'

Richard

 

[iploffy]

As for the springing problem as Vac Pipe is thicker than air pipe and the ridges set about 1/2inch apart on the prototype could you not get a buffer spring and gently pull it open attach it to the model then cover it with heat shrink then cut to the required length.

Ian

 

[Dog Star]

....  the ridges set about 1/2inch apart on the prototype, could you not get a buffer spring and gently pull it open....  then cover it with heat shrink.

That ought to work, the local "friendly" garage has a wide selection of heat shrink tubes so sourcing that material that is not going to be a problem.  I shall have to do some research as to supplies of springs which are of suitable diameter and coil pitch....  otherwise I shall have to try winding a spring from brass / copper wire.

Thank you, Graham

 

[Rob Pulham]

Hi Graham, do you have Boyes Stores near you? They have a crafts section that has soft brass and copper beading wire in all sorts of gauges I have a selection in gauges 20 through to 34 (the 24 gauge is what I used for the pipe work on Papyrus). The most I paid was £1.99 a roll, most being either 99p or £1.25

 

[Dog Star]

Hi Robin,
  Boyes is not a name that I recognise...  on the other hand, wire for "beading" rang a bell and the Good Lady confirmed that Hobbycraft does have such material...  and that store is located between here and the supermarket!!!!

To be honest, making the flexibles for the water, vacuum and steam heat are going to be the least of the problems for the tender.  Peter spent most of the afternoon making a bucket, for the "hole-in-the-floor", out of copper shim - now we need a casting for the tap on the lower front of the tender.  The prototype looks just like a plug-cock, projecting at right angles from the tender front, with the plug spindle horizontal and the outlet turned through 90 degrees downwards.  I have yet to find a supplier of such a part so any suggestions greatfully received.

Similarly, the tenders paired with A4 engines have another water cock on top of the shelf, behind the water scoop handle.  The outlet from the cock seems to form a vertical loop on that shelf and then run down the front of the tender against the side sheet...  finishing about 10" from the floor - probably a drain or an overflow.  Any ideas as to the purpose of the fitting/pipe and method of operation?

regards, Graham