Two gable ends conquered, we return to the middle gable which holds the hearth.
A bed of mortar is laid where the clay flue pipe shall rest within the chimney.
Set the pipe in place and level it – then fill all gaps with slips of stone loosely placed around the lip of the pipe with a wee bit of mortar (below).
As seen from beneath by looking up the chimney (below) – no gaps!
The space surrounding the pipe is then filled with a dry mix (2/1 ratio) of coarse sand and ordinary hydrated lime (below). This will facilitate heat expansion of the pipe. It should be covered & kept as dry as possible as building continues, adding pipe sections & liner as it grows. Don’t be tempted to use rubble as that would create hotspots. Neither be tempted to use cement as this would lead to cracking.
A slight chill creeps into the air and the swallows not yet departed – they gather themselves on telegraph wires to make plans.
limewindow 
What a delightful post – and I learned something, as ever. Because you recommended him, I bought both the Pat McAfee books and had them sent from Ireland – Irish stone walls and the home building book. Have read every word of Irish Stone Walls and am still waiting for the second to arrive in Tasmania! So far, I am delighted – the best book on stone walling I have found yet! So love and thanks from Tassie! xoxxoo
Hi Chloe – it is safe to say that without Pat McAfee’s work our stone built heritage might well have continued to collapse into oblivion & ‘Irish Stone Walls’ has been described as the ‘bible’. The stone community here will be getting together soon, with Pat and others on the smallest of the Aran Islands – you would love it, http://www.galway.ie/en/Services/Heritage/Final%20Brochure%202012.pdf
That was a very detailed bit of info about the flue insertion – where/how far up the chimney before the clay pipe & packing are supported. Is it high enough for example for an iron cooking cradle (that’s not the right word, ..”crane”..?) to be reinstalled? Or an open fire with a suitable wide hood?
Yes the flue pipe is tucked up the chimney by 20” or so allowing room for cooking crane and other paraphernalia but a small black stove would privide the most effective heat – with or without back burner depending on organised water supply.