I would like to know:
- What is the technical term for the hole made in this soap holder.
- I cannot figure out how it was done to make it evenly curved
What is the technical term for the hole made in this soap holder.
I'm not sure there is a specific term other than to say it's been hollowed.
I cannot figure out how it was done to make it evenly curved
There are a number of ways this can be done today. Excluding fully automated methods (CNC) I think there are three main hand-operated possibilities. In no particular order:
It can be fully hand-carved, so one or a combination of curved-edged tools — gouges, curved knives (hook knives), scorps or travishers — could be used to do the basic hollowing out, then a certain amount of scraping and/or sanding to finish off.
You can use various types of cutting bits (burrs or rotary files) held in a power drill and cutting disks in angle grinders to carve out wood with astonishing speed. Generally these leave a pretty rough surface so a fair amount of scraping and/or sanding would be needed to complete smoothing.
It's also possible to do this entirely by sanding, using one or more sanding devices again held in a drill or angle grinder and worked over the surface. Starting with a very coarse grit (possibly below 60) you can hog material off surprisingly quickly, then you just move up through the grits until the surface is as good as you want it.
Off the top of my head, I thought of three different ways:
You may use a gouge to do this. A gouge is blade similar to a chisel, but rounded. They hollow out spoons, bowls, clogs, etc.
If your soap dish were round, then it would probably be easiest to turn it on a lathe, to cut out the hollow part.
A milling machine can easily duplicate a shape like this. There are CNC milling machines, which are computer controlled and will be programmed to cut a shape out, and there are copy milling machines, which copy an existing design, by following the contour of some part, and moving the cutter in the same way.