MORE 5700 PROGRESS

By Doug Hewson

HERE IS another update on progress of the design of the GWR 5700 pannier tank. 

I have tried to draw the drain cock arrangement as near to the full size as possible (but not easy with the upside down cylinders!) so I have made use of off the shelf drain cocks from Dave Noble as they are virtually correct for the Pannier.  I have altered the rodding to suit but one of the problems was solved when I studied a photo sent to me by John Brandrick. Excellent!  I could not fathom out the linkage from the cab to the bottom cross shaft but the photo from John showed a little rocking shaft on top of the middle right hand splasher which solved all.  I also really appreciated the photos from Matthew Pulzer’s brilliant web site (well worth a Google) as the photos are excellent.

The actual arrangement of the drain cocks on the cylinders came from another friend Rob King who had fitted drain pipes down the back and front of the cylinder block to drain cocks mounted in bosses on the underside of the steam chest.  It makes the arrangement quite simple (I think!) and follows full size practice about as near as we will get.

A few weeks ago we collected samples of the cab and bunker kits for both the 5700 and the 8750 classes and Frank Osgerby has ironed out a few minor problems and as he says the rest all fitted together without any problems. 

I have made formers for the rear corners of the bunker and after a bit of jiggling the corners went fine as you can see from the photos.  However, it was far easier forming the back corners when I had the sides or the bunker in one piece so I am going to make the production ones like that.  This eliminates the horizontal joint at the rear corner so they will just require a line scribing on the plate to represent the joint where the curved side joins on to the formed top corner piece.  It was far easier to hold for forming than when it was in two pieces and if anyone spots the difference after it has been painted they can answer to me.

However, one thing I failed to account for was the fact that the Pansy is about 1/2” higher than the scale outline so Frank had to add a half inch strip all round (from the offcuts of the laser cut kit) to raise the cab height to account for the oversize boiler.  We will supply the kits for both the 5700 and the 8750 in both sizes so that they can be used for Pansy or for anyone wishing to improve a Pansy.

The other thing which has arrived is the casting for a pair of crossheads.  These have been lost wax cast in stainless steel (machinable!) and are as near to the full size as I could make them.  The castings have been made so that they can either be machined conventionally or they can simply be white metalled as per full size and then machined.  That is what I did on my 4MT.

My next job is to complete the laser cutting drawing for the frame stretchers.  I got it half completed with everything drawn out in the flat for laser cutting but the new laser cutters don’t want that as they have a programme for developing the flat plate so all I need to now is supply the drawing for the bits we need and they will do the rest.  I have just got to gather all the relevant bits on to one drawing and send it to them.  If anyone wants stretchers let me or Mike know.  The stretchers will come ready formed and the laser cutters work to microns.

Drawing 5 is now complete and available from Mike Hewson either by E Mail on dhewsonmodels@btinternet.com  or by telephone on 01507 588 592 (this is a new number as he has moved house.

Earlier updates: no. one (GA dwg), no. two (boiler dwg), no. three.