Boiler expansion brackets

Hello from a new member. I have been building Martin Evans' 5" 'Springbok', rather slowly but with much pleasure (usually), and have reached the stage of fitting the boiler, which was professionally made, onto the frames/rolling chassis. Can someone please advise the correct way to secure the expansion brackets at the rear of the boiler? The drawings suggest fixings into the boiler itself to secure pieces of angle but before making holes in an expensive part of the locomotive I think I should know the correct method.

Any help and advice would be most welcome.

Peter

hi peter,

you need to check with your club boiler inspector what is considered acceptable. some club boiler inspectors dont like holes being tapped into the boiler for expansion brackets and firehole door fixings etc.

cheers,

julian

Hello Peter,

Many years ago I came to the conclusion the more holes you drill in a boiler the more chances you have for leakage, so these days I never fit expansion brackets, angles or what ever, Martin Evans and before him LBSC style to a boiler, now I'll always fit a couple of pieces of either suitably sized angle or pieces of square material to the frames and sit the boiler down on it's foundation ring onto the angle; it's a far easier proposition when getting the boiler level in the frames; the boiler will never jump off, it being held in place by the plethora of pipework together with the cab! It's an easy enough task on the full sized locomotive to fit brackets etc but not so simple in our sizes.

As Julian has mentioned there is the odd inspector out there who is adverse to the idea of drilling and tapping into a boiler and although it may be seen by some as not best practice I cannot recall the method being prohibited in the current publication from the Model engineering liaison group.

Regards,

Bob Youldon

The best way is to get your boiler maker to fit the brackets during manufacture.

I asked the maker of my boiler to do this as it is an excellent idea. The problem is that boiler drawings always seem to show a non-dimensioned position for the boiler brackets so he was unable to do so.

i agree with Bob entirely and have, in most of my locos, fitted angle or bar to support the foundation ring, rather than add expansion brackets. expansion brackets can be a real pain! there is plenty of pipework, as Bob says, to hold the boiler down, plus the cab.

i never turn a finished loco over/upside down with the boiler fitted as all sorts of crap and muck can get in the clack valves and manifold

cheers,

julian

Welcome Peter,

Neil

Gentlemen,

Thank you all for your replies and welcome. On inspection there seems to be no great difficulty in supporting the boiler as described by Bob so I will go down that route. What about the firehole door though?

Peter

Hello Peter,

Make up your firedoor complete on a frame and attach the the complete unit onto the boiler with a pair of studs; the backhead on the Springbok design is from .125" material so there is adequate material to accept a reasonable thread, make up a pair of studs with the thread for the boiler slightly on the tight side, make them from either drawn bronze or preferably from a piece of monel, drill the boiler right through and tap using a taper tap with plenty of tapping compound such as Trefolex, don't tap right through but leave a nice tight taper thread, wash the area clean with some meths of all the tapping compound, now anoint the threads of your studs with a good sealing compound such as Heldtite and fit the studs using a stud box, Your nice door and frame can now be fitted onto the studs, give them a dab of graphite grease and fix the frame using a couple of brass nuts and washers. Job done!

Regards,

Bob Youldon

hi peter,

the firehole door fixings you need to consult your club boiler inspector for same reasons as the expansion brackets.

cheers,

julian

Thanks for the replies. Bob, thank you for the detailed description, it all makes good sense. Julian, it is obviously time I joined a club! All my queries and problems so far have been solved by reading up or re-making the part but the boiler and its fittings require the knowledge and experience available in a club so I'll look into it. Oxford is not too far away.

Regards,

Peter