After some discussions around the hot-air engine posted in the Plans area, I decided to get off my duff and make the mini-fan I've been thinking about for a while. Since I asked for this forum, I'm going to post parts as I make them, with plenty of commentary and gory details, and encourage others to do so too, no matter what their experience level. I'm never one to follow directions exactly, so this one is mostly based on Jerry Howell's "Mini Sterling Fan" plans, but with modifications and additions from Dr Senft's Moriya (and the half-size version) and other things I think up. Hopefully it'll all work in the end, since this will be the first Stirling for me. Anybody with more experience is welcome to chime in with hints and other ideas as I track off into the deep end. Much of the reason for building in this scale is I'm working with scraps from a friend's CNC machine shop. You'll note that "one inch" is a very common dimension for major parts, with very few larger than 1" in two dimensions. That works well for the scraps. My usual pace is one part a night, though that varies a little. Somehow easy parts mostly end up taking all night too.. I'm definitely no Master of the Machine Shop, mostly self-taught and barely getting by on the experience from previous screwups. So, going with the rake60 patented 'make the hard part first', I started off with the displacer cylinder. Jerry calls for this all to be one piece of metal, but not having a slitting-saw the right size and not being keen on long overhangs of the parting tool needed to clear the base, I elected to make this in two parts similar to Moriya. In addition, the parting tool I had handy wasn't the thickness specified for the fin spaces, so those also had to be resized. Two design changes and I've not even made the first part yet. Poking in the scrap box, I went with brass for the finned piece and aluminum for the base. Brass conducts heat pretty well and it looks nice, so there it is.. Three changes, now.. Senft's instructions for fin cutting by putting the compound parallel to the lathe axis and cranking it to set the fin-space distance works. I started out with a table of spacings, but ended up just zeroing the dial and cranking the same distance each time. Then, thinking about how to attach the the base, I thought ahead to the hot cap and how I had some nice 1" round stainless. The plans call for 1" square, which I don't have, but by moving the mounting screws in a little, not only could I add room to hold the fins on, but I could fit the mount screws into a 1" circle. That turned out great. Even though there will be some insulators holding them apart in the end, 1" round fits perfectly inside the 2-56 SHCS heads holding the fins on. I'll probably counterbore them flush anyway, but I was impressed with my own serendipity (a note on the photos. Right now they're 'as-cast'. I'll tidy them up later, hopefully. (for scale, the fin block is 1"x1"x1.2") Well, one weekend over and I have a new shiny paperweight, for small values of 'paper'.. Onward to the hot cap and power cylinder.