locustman

Newbie and first post. I can answer some of your questions as I had to make one similar to the Diamond. They're spark catchers or arrestors. Designed so that large ash or embers fall down between an inner and outer flue, smaller embers or sparks caught usually by a mesh screen. Used on wood burners and more popular on your side of the pond, as coal was fuel used over here and we don't have vast areas of prairie to set on fire. The Taper will be shaped to improve draw on the fire. Not much relevance to forges, unless your some how sending vast quantities of sparks up the chimney and sending the neighbourhood up in smoke!