Hi Anders,
That looks like a pretty good effort without a lathe, even if you borrowed one for the piston. Well done, and congratulations on getting it running.
You last posted before I joined the forum, so I did not know you were working on this one. I have also built a small single acting oscillator using tube for the cylinder, though it was around 10 mm or 3/8 brass tube. I have a lathe, so made the piston to suit, but without a lathe, some oil grooves wound with cotton or other suitable packing material on a piston made from the closest size rod you can source will work quite adequately, especially if you can size it a little with file rests and your drill. A bit larger size is less critical in my experience, some 3/8 or 1/2 inch hard brass tube is a good size basis to start with.
Eventually the lathe will come, in the mean time you will have plenty you can do with your other skills. Have a look at Steam Guy Willy's freelance engine for what can be done with files, skill and patience. Though I believe you would need a lathe for a double acting engine to get everything on the cylinder concentric. Others might also comment on this.
I can understand deferring the lathe until the family is grown, I had to wait until all had left home, there are always other pressing purchases with children. If you browse old threads on the forum, you will see people are making amazing engines on very small lathes if you have no space for a larger one.
So what is your next project now?
MJM460
