Fowler Build

[MrT42Participant @mrt42]

smokebox

[MrT42Participant @mrt42]

Hi

Ive just started to build a 3inch Fowler traction engine and have hit my first hurdle. I cant source a piece of tube suitable for the smoke box.

The drawing specifies 190mm od 5mm wall thickness. The smokebox ring casting is 185mm od (un-machined) , so id of tube needs to be slightly less. I need 200mm length. I dont really want to get it rolled and welded but not really sure what else to do.

Does anyone have any suggestions please.

Thanks

Jonathan

[JasonBModerator @jasonb]

Rolling and welding is the usual way to go, same as the wheel rims, someone like Ashby will do them and are traction engine friendly.

Other option is a thick wall tube and bore it out which can sometimes be taken advantage of by doing away with the front door ring and and adaptor ring onto the boiler. M-Machine have 193.7 x 12.5 wall.

193.7 x 6 is a structural size so you may be able to get an offcut of that, and adjust other parts to suit

Edited By JasonB on 28/06/2021 13:28:51

[Anonymous]

Machining a thin walled cylinder is a tricky but avoidable problem. I bought my smokebox rolled and tack welded. I completed the seam weld, welded in a rolled length of BMS and machined the smokebox door ring to fit. I then drilled all the circumferential holes:

The ring was bolted to the smokebox and used to clamp the smokebox to the small faceplate so I could machine out the rolled BMS to the average diameter of the boiler:

Andrew

[Former MemberParticipant @formermember12892]

[This posting has been removed]

[Paul KempParticipant @paulkemp46892]

I would say about the only useful information from a copper boiler drawing if you want to make a steel one is the overall sizes, barrel diameter, overall length, width and height. 2 completely different materials with completely different properties.

Paul.

[JasonBModerator @jasonb]

Even diameter would only be a guide as you would have to go with available tube sizes.

Steel also has knock on effect of different stay layout affecting horn plate drilling. Different dia & possibly external thickening pads affecting smokebox ID, cylinder and weigh bracket undersides and a whole host of other small items.

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