Thanks John.

3-1/4" minus 1/8" for the wrapper gives 3-1/8" for the width of the throatplate.
Making a 3-1/16" hole in this would leave the flanges only 1/32" thick. I think
I'll be making the hole and stepped ring 3" dia so they just touch the flange.

Looking at the drawing again LBSC gives the inner width of the firebox as
1-3/16". Add 1/8" for the inner wrapper, add 3/8" for the foundation ring, add
1/8" for the outer wrapper gives 1-13/16", which is 1/8" less than the distance
between the frames. That should just leave room for the stay heads.

I'll email you about the Annie Bodie articles. I don't have them, but my ME
Index says that article on page 548 of Vol 69 refers to a 3" ID boiler tube
which would be 3-1/8" OD. Perhaps that was just for AB though.

Graham.



--- In halfinchlivesteamforum@..., "John Baguley" <baggo@...>
wrote:
>
> Hi Graham,
>
> The construction notes on the Dyak boiler are pretty vague as LBSC refers back
to the boiler for Annie Boddie all the time.
>
> The boiler barrel is 3¼" diameter and is joined to the throatplate with a
stepped ring. The throatplate has a hole of 3-1/16" dia. into which one end of
the stepped ring fits. The maximum width of the firebox wrapper is the same as
the boiler barrel.
>
> I presume the width of the firebox between the frames is the same as Annie at
1-7/8".
>
> The wrappers are both 16swg (1/16") as are the crownstays.
>
> If it would help I can email you the Annie Boddie boiler notes.
>
> John
>
>
>
> --- In halfinchlivesteamforum@..., "graham9238" <g4iln@> wrote:
> >
> > 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.
> >
>