I'm attempting to build a Dyak Boiler, but have run into problems with the
dimensions on the Kennion's drawing.

The smoke box is shown as 3 1/4" OD and it appears that the boiler barrel is
this size too. However the maximum width of the firebox is also shown as 3 1/4"
diameter. This can't be true, as twice the throat plate flange thickness and
twice the wrapper thickness must be added to the barrel diameter to give the
firebox width. So my first question is what is the correct boiler barrel
diameter?

What is the width of the part of the firebox which sits between the frames? The
drawing shows quite a large gap between the firebox and the frames rather than a
tight fit. Knowing the width I can work backwards to determine the size of the
inner firebox flanged plates.

Finally what is the thickness of the inner and outer firebox wrapper and the
crown stays? It's not shown on the drawing.

Thanks.

Graham.