Boiler build

kevingambrell · 24-01-2007

Would any one be interested in a photographic record of the next boiler I put together?

Its a 2 inch fowler Superba in steel. Should take about three weeks with some give for cold weather.

kevin

**Bunkerbarge** · 24-01-2007

Very interested. I would love to see a build thread on such an item for nothing more than the interest of watching how such an item goes together and how you design and calculate the dimensions.

flytilbroke · 24-01-2007

I would like that, although I admit not being into active model engineering.

IainM · 24-01-2007

Yes please, I for one would really like to see a step by step build thread.
I'm never too old to learn!!

kevingambrell · 24-01-2007

Ok well I suppose to start with a picture of what im putting together would help and a few details. Its a Fowler Superba compound ploughing engine.
Well infact its two of them no point in having just one engine and a plough.
Building two isnt that much more work as jigs and tools are already made for the second engine. Its a long job with a four year build time and another year for painting.
Once the boiler is started it should take about two weeks to get to the pressure test.

Overall length 50"
Overall width 18 1/4"
Overall Height 27 3/4"
Cylinder LP 2 1/4" Bore x 2 1/4" Stroke
Cylinder HP 1 5/8" Bore x 2 1/4" Stroke
Working pressure 120 psi
Steel Boiler 25 1/2" x 6" dia
Flywheel 9" dia
Front Wheels steel 10 3/4" dia
Hind Wheels steel 13 3/4" dia

The following link has a few pictures of the last engine and the boiler as it was made. http://s138.photobucket.com/albums/q268/kevingambrell/

This one is a bad picture of the engine in question.
http://i138.photobucket.com/albums/q...ll/superba.jpg

kevin

**Bunkerbarge** · 25-01-2007

That's a fair size boiler. I saw a number of such machines at my last Model Engineering show at Harrogate and they were happily pulling a truck with a couple of adults around.

kevingambrell · 25-01-2007

Hi Richard
the Superba's were huge engines, just standing next to one working is fun. Each year Preston services in Kent have a ploughing show and watching two Fowlers drag a plough 400 yards across a fied is interesting.
The order went in for the steel today so with luck next week I should start cutting and maybe some of the forming depending on how cold the workshop is. Most of the castings are almost ready, giving me a chance to maybe machine the cylinder block if I do ill put some pictures up.

kevin

kevingambrell · 25-01-2007

Hi
just as a starting point I thougt i would show the formula for working out the boiler plate thicknes.

P= Dx W.P. x F
__________
Sx2xRxCxT

Where P = plate thicknes (barrel) in inches
S = Ultimate tensile strength in PSI (copper 25,000 PSI Steel 60,000 PSI)
F = Factor of safety from 6-10 as a rule 8
R = riveting allowance (.8 for welded brazed or silver soldered)
D = Diameter of barrel in inches
C = corrosion allowance (for steel only .25 inch and bellow .5 to .8)
temperature allowance (copper at 400F =.7 200F = .87)
W.P. = working pressure

All flat surfaces should be atleast 1/3 thicker than the boiler barrel. Stays should not exceed a pitch = to

tx800
_____
W.P.

t = thicknes of inner firebox wrapper

Firebox stays should be twice the thicknes of the inner firebox wrapper.

Kevin

dipstick · 27-01-2007

thats is a large engine for 2" model, are they the drawings and castings from brunel models? what other engine have you built? and this boiler is it going to be a welded or hot rivited.

i should really get some pics of this burrell i am build up on the forums, as i have nealy finished the cylinder block.

chris

kevingambrell · 29-01-2007

Hi
Well the boiler steel is here and so are the rods. Just need a few degrees warmer in the workshop and im away with the welder!

Chris the boiler will be all welded using a mix of Mig and stick. The firebox will be mig and the other welds stick. trying to rivet a boiler this small is a pain in the backside and a bit on the longwinded side. That said all the stays will be rivited before welding over and theres a shed load of hem all in 1/4 MS.

The T rings will be machined form billet MS and I may include pictures of that as I go. The rear T's are split and the front wheel T rings will treppaned from the back T ring billets as I always do.

Oh the joys of steam!