Steam Union, Manifold & Pressure Gauge (January 2015)
Steam union
The steam union transfers steam from one of the outlets on the steam manifold and transfers it to the injector and water lifter stop valves. This part was made from a solid casting as had the following points of interest.
Steam union
The steam union transfers steam from one of the outlets on the steam manifold and transfers it to the injector and water lifter stop valves. This part was made from a solid casting as had the following points of interest.
- The two stop valve connection threads would be very difficult to prepare and cut on a lathe as there is no easy surface to clamp the part in the chuck. Thus, the threads were prepared on the mill by cutting in a helix about the centre of each.
- The threads were so close together, that a die holder could not be used to grip the die. Instead a very thin walled tube was fashioned to hold the die.
- The majority of the outer surface was a hand filing operation - which was very tedious.
- As was expected the casting was not square or straight, thus a best endeavors approach had to be used to make the outer surfaces as parallel as possible which constraining the mating threads properly inline.
Steam manifold
The steam manifold connects to the top rear of the boiler and transfers steam to the pressure gauge and steam union. The outer surfaces of this part was mainly a hand filing task, which was conducted with the best intentions to keep the connecting surfaces parallel and maintaining the key dimensions. Once dimensionally complete the part was then transferred to various positions in the milling vice to complete the ten drillings and four internal threads! Two plugs also had to be manufactured, a simple brass turning operation, to blank off two internal drillings.
The steam manifold connects to the top rear of the boiler and transfers steam to the pressure gauge and steam union. The outer surfaces of this part was mainly a hand filing task, which was conducted with the best intentions to keep the connecting surfaces parallel and maintaining the key dimensions. Once dimensionally complete the part was then transferred to various positions in the milling vice to complete the ten drillings and four internal threads! Two plugs also had to be manufactured, a simple brass turning operation, to blank off two internal drillings.
Pressure Gauge