I have finally got to the stage of cutting the hole for my dome bush in the top of the boiler. I don't really want to mess it up at this stage so would welcome suggestions as to how to cut it. The hole is 1 3/16" diameter and I wondered whether to use a holesaw? Is that is a good idea and if so what speed should I use? Any other suggestions please?

Thanks – Bob

Thanks for those answers – I like the idea of the holesaw but I am a bit worried about it snatching or worse! If it works the hole would hopefully be round enough to fit the bush to. Thanks also for the tip of retracting the two pins. On the other hand chain drilling also appeals as it means the smaller holes are less likely to go wrong – luckily the tubes are not yet fitted to the smokebox tube plate so they can still come out with the firebox (that had occurred to me!). It would also give me a bit of filing practice……

Thanks again for the replies – Bob