Now actually started building my Hot Ai Engine. Have finished the patterns which are now in Totnes for casting. And the transfer cylinder has been turned out of a piece of 1 1/4” tube – the most daunting bit of boring I’ve ever done as the finished wall thickness is only 1/32”. On one cut the the swarf came out in just about one single piece – right across the workshop and then some!! (Sorry about the picture orientation, but can’t find the rotate button!!)