Saturday, 6 February 2016

Tyseley: Another Riveting Day...

Hi all. Today I was on my way over to Birmingham for another day volunteering at Tyseley Loco Works. Its fair to say that the weather was rough - all rain and wind - with plans for it to get even worse as the day wore on. A hardy bunch of volunteers had turned out despite the rainstorm and work began at around 10am. The object of the day was to finish off riveting the foundation ring of 7029. The foundation ring, for those not familiar, is the seal between the inner and outer firebox sheets. Some call it a mud ring, as the various scales which leave the boiled water during evaporation settle in the foundation ring due to it being the lowest point. Having helped with some hot riveting the other week as the 'runner', this week I was playing the part of the 'warmer'. Here are some of the rivets prior to heating...
Wearing all the necessary PPE, three of us began riveting during the mid-morning. The job of the warmer, quite obviously, is to heat the material ready for riveting. Hot riveting is done with the metal in a literally red hot condition so that the hammer and jammer can crush the rivet into the desired shape. In the case of the GWR Castle, the design requires the crushed rivet on the outer firebox sheet to be flatter in size due to limited clearances when the boiler is placed between the frames. Designs do vary, with some engines having what looks like another rivet head almost identical to the 'factory' type crushed onto their end after riveting.

As the warmer, I was in charge of the oxy-propane torch and was warming the many rivets up on the warming table. Naturally, it is HOT work - every part of you seems to start baking! It is however interesting to do as the metal needs to be critical enough to be crushed easily without losing temperature at an alarming rate but also needs to not get so hot that it melts. There is a very fine line between good and gone let me tell you! With the rivet hot and ready to go, the rivet is taken with tongs and quickly handed under the foundation ring and fed into the required hole from the inside of the firebox. The head therefore stays on the inside, as per design. A jammer is then placed on the head to secure it whilst the hammer on the other side uses compressed air to crush the rivet with the cylinder inside bashing the bullet against the forming tool which thus repeatedly bangs the rivet into shape. It takes more skill than I've described to crush rivets but its hard to write what I mean! A row of crushed rivets is seen below, against the outer firebox sheet...

We went on riveting for the rest of the day, eventually finishing 7029's foundation ring completely. Its amazing just how many rivets go into a GWR Castle's foundation ring alone, let alone the rest of the firebox and boiler. Due to the massive pressures attempting to force their way out at every inch of the boilers plate-work, the countless fixings (stays and rivets) are necessary! Below is another video that is available on YouTube. It shows hot riveting taking place on the foundation ring of another Great Western engine - a 56XX type Taff Tank 0-6-2. The variation between designs can be spotted as you will notice that the rivet is crushed into a larger head on the upside-down firebox of the 56XX, unlike the Castle where a flatter outer head is required...
Hot riveting is very hard, loud and extremely noisy work but it is interesting to see the process in action. It is also interesting to appreciate the speed of the process. From the warming table to fully crushed takes only a matter of seconds as the room temperature and of course the chilly plate-work of the boiler will steal the heat away very quickly, making crushing almost ineffective. We finished at just after 5pm, with the persistant rain still beating down hard on the shed roof of 84E's fairly recent extension. All in all it was another very enjoyable and rewarding day volunteering at Tyseley and 7029 can now enjoy her fully riveted foundation ring. The 1950-built Castle is progressing - one more step closer to steam. Best Regards, Sam...

No comments: