Hi,
I just wanted to share the experience I had today. Maybe this trick is not new, but it is new to me. And I found it out today.
I needed a brass tube for a cylinder (gas/air compressor). The tube was a thin-walled drawn brass tube OD 20mm, ID 18mm. I made the experience, that reaming always fails. Either I get chatter (thin-walled) or a bad surface (brass tubes are a bad material to ream).
So I turned some hard wood on the lathe, just 0,1mm below the required diameter, put some grinding paste (the fine grid for valve lapping) on it and let it rotate in the lathe. Slipped the tube over it and moved it back and forth while slowly rotating it. It took just a few minutes to have a shiny and round surface! The neat trick is: If the OD of the dowel gets to small, put some water on it. Thus it will expand.
Made a really snug fit!
Hope this helps someone.
Nick