cutting holes in boiler tube

[Bob LambParticipant @boblamb44747]

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

[Bob LambParticipant @boblamb44747]

[david homerParticipant @davidhomer12226]

I put a 2 3/16" hole in a 6 1/4" tube for mine, using a hole saw, use as slow a speed as possible make sure it is fastened down well. The other thing I did was to replace the drill with a solid bar as a guide once I had drlled the pilot hole. I used WD40 as a cutting lubricant. If the arbor for the hole saw has 2 pegs that go in the top of the hole saw like mine had, I left them retracted so that the hole saw screws up against the arbor, I found this stops it wobbling about.

David

[julian atkinsParticipant @julianatkins58923]

hi bob,

chain drill and file to a plug gauge or the turned dome bush. do before fitting the boiler tubes!

cheers,

julian

[Bob LambParticipant @boblamb44747]

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

[JasonBModerator @jasonb]

Use a step drill to take it out to 1" and then finish with a boring head.

[Author]

Posts