Brilliant trick of sanding the bottom of the dome over a piece of tubing like that. I have just turned two brass domes of my own, and rough-filed the bottoms, but I have been puzzling over how I would get that bottom curvature to at least be close to my boiler radius. Great idea.
Incidentally, turning model parts in a hand drill works well for a lot of things, including even turning down wheel flanges. It's not as accurate as a lathe, of course. But in my experience, we really don't need that level of precision in our models. A decent electric drill turns true on its axis,
and we aren't putting a lot of cutting pressure on it. The normal issues that one addresses with a lathe such as run-out and spindle deflection really don't matter as much as you might think for situations like this.
After all, a dome turned within .005" would look perfect to our eyes,
while a machinist would probably think that .005" of error would be
2mmFS Boiler Fittings Without A Lathe
in Modbury - 2mm Finescale (Brunel's Baulk Road)
A blog by Ian Smith in RMweb Blogs
Posted
Brilliant trick of sanding the bottom of the dome over a piece of tubing like that. I have just turned two brass domes of my own, and rough-filed the bottoms, but I have been puzzling over how I would get that bottom curvature to at least be close to my boiler radius. Great idea.
Incidentally, turning model parts in a hand drill works well for a lot of things, including even turning down wheel flanges. It's not as accurate as a lathe, of course. But in my experience, we really don't need that level of precision in our models. A decent electric drill turns true on its axis,
and we aren't putting a lot of cutting pressure on it. The normal issues that one addresses with a lathe such as run-out and spindle deflection really don't matter as much as you might think for situations like this.
After all, a dome turned within .005" would look perfect to our eyes,
while a machinist would probably think that .005" of error would be
"terrible" on a lathe.
Thank you for the post. It is a real help.