Pipework

Modelling the Kerr-Stuart Brazil Class 0-4-2ST locomotive in 16mm scale. - Keith Bucklitch

Pipework

 

  1. Steam pipe.
  2.  

    Make this from 3/32" copper tube. Cut a piece 3 inches longer than the boiler. You need an olive and 5/32 x 40 gland nut on the front end. Make an olive by turning a piece of 1/8" brass down until it will enter the nut freely. Centre and drill 3/32" diameter. Shape a cone at the end and part off 1.5 mm long. Place the nut on the pipe, clean the end and place the olive in position. Silver solder the olive in place. Place the boiler in position in the smokebox and determine the curve needed on the pipe. Make the first curve to bring the pipe vertical on to the steam tee. Insert into the firetube through the smokebox. It is likely that you will have to make further curves to the tube to fit comfortably on the steam tee. Adjust the pipe until the nut can be fitted to the tee. I made a spanner by filing the shape from a 3" length of 3/8" x 1/16" mild steel strip. This was bent in a 'Z' shape to get behind the exhaust pipe and tighten the nut. About 3" of pipe should now be emerging through the firehole door. Mark about 3 mm away from the door, remove from the boiler and cut to length. Make a female end from a piece of 7/32" hex brass. Drill this 3/32", open out to 5/32" for 3 mm deep and tap 3/16" x 40. Part off at 4 mm. Silver solder this to the end of the steam pipe. Reinsert the steam pipe in the boiler, connect to the steam tee and the female connector should emerge through the firehole. Bend this down so the door can be closed fully. We now need a short piece of pipe with a male connector at the lower end and an olive and nut at the top end to connect to the regulator. When making pipework, I often find it helpful to use a piece of 1 mm copper from some electrical cable to work out the route and length of tube required. This is much easier to bend than the tube (and cheaper). When you have worked out how much you need, cut to length, solder on the connector and olives (not forgetting the nut), bend to shape and connect in place.

     

  3. Blower.
  4.  

    We need two pieces of 1/16 copper pipe for the blower. One length connects the blower valve to the hollow stay through the boiler. This is similar in construction to the short steam pipe described above. The second piece is inside the smokebox and leads into the chimney. This should be long enough to emerge just above the top of the petticoat pipe. If a small nozzle is fitted with a 10 BA thread, it can be removed in the event it becomes blocked. Measure the length required with some copper wire. Cut a suitable piece, fit an olive and small gland nut made from 5/32" hex brass, with a 1/8" x 40 thread. Thread the other end 10 BA, fit a small nozzle from 3 mm (1/8") brass hex, bend to shape and insert in position.

     

  5. Water feed.
  6.  

    We need a 3/32" pipe leading from the ENOTS coupling in the left side bunker, beneath the boiler to the clack valve on the right hand side. The drawing for this is not shown. Obtain the length by using a piece of copper wire, cut to length and solder the appropriate couplings at each end. Cut a slot in the cab side front for the pipe to emerge and bend to shape. Fit into place.

     

  7. Pressure Gauge.

 

A commercial pressure gauge can be obtained from several suppliers. I like to use the 3/4" diameter, 0-60 psi gauges as these are usually easy to read. The safety valve should be set to lift at 30-40 psi, so we should have plenty of leeway with the gauge. The pipe must be bent in a 'U'-bend to form a sump and prevent raw steam reaching the gauge. Usually you are supplied with a nut and olive with the gauge. Make sure that you have one suitable for 3/32" pipe. Fit an olive and nut to the other end and silver solder in position. Bend to shape and fit to the boiler. Adjust the position of the gauge face so you can see it easily.

 

Next Dome and Water Tank.

If you have any questions, or comments or find any errors in these notes please contact me by email. Email Keith Bucklitch.

Copyright © 1998, Keith Bucklitch
Last Edited - November 1998
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