Manhole door for Fowler R class/A4

[MARK RIGG]

The drawing number for the MANHOLE COVER ( DOOR ) is 45951 and an earlier drawing No .33786 . Both these drawings are at MERL .

The drawings show the Manhole Cover - the door itself the same size but of different radii to suit each of the Fowler standard boilers . I no longer have my copies of these drawings , but I think from memory the actual door is a steel pressing NOT a casting.
I`m not sure whether a replacement door as a casting would be acceptable to the boiler inspecting people. As a casting, this might involve a redesign of the door itself .

To make a pressing in such heavy section for a very small quanity would be very expensive - a lot of expensive tooling would be required to stamp the door in its flat shape and then more tools to form it to suit the internal diameter of the boiler barrel .

If this is not done accurately I can see a danger that the door won`t seal properly and the joint blowing out .

There is / was a firm in the Glasgow area that specialised in Manhole Doors , probably for the flat ends of marine boilers. Whether they would have anything of a suitable size in the flat that could be reworked, might be worth investigating .

MARK

[MARK RIGG]

Further thoughts on the above .

The firm in / was in Glasgow is CHARLES McNeil Ltd and I think they are now part of Motherwell Bridge Group . I seem to remember talking to them about Manhole Door bridges awhile ago.

Another possibility is ABBOTT & Co Ltd . in Newark . They make and supply components for and manufacture air receivers and pressure vessels . Might be worth talking to them.

Another suggestion is to machine it as a `one -off ` from a thick piece of plate on a vertical CNC machining centre with a 4th. axis.

I would be better to start with a thick piece of plate rolled / formed to the approximate radius ( by Deepdale in Dudley or Barnshaws in Wolverhampton ) . This would save on the machining time and it would then be a relatively straightforward job on a suitable CNC machine to machine from solid all the detail and the required radius .

Still not a cheap project .

MARK