Hi,
Woodturning today !
Here is a hollowing tool :
http://www.labellenote.fr/photo/gal_..._creusage1.jpg
http://www.labellenote.fr/photo/gal_..._creusage2.jpg
The blade is made of HSS, it is sold for an edge deburring tool.
It is screwed on a flat section , filed following the diagonal of a square section steel bar.
Those little blades are very interresting, when the cutting edge is no more sharp, you just have to unscrew and turn it a few degrees. And when you have finished one, you can yet turn it upside down ...
you have for your money ...
http://www.labellenote.fr/photo/gal_..._creusage2.jpg
As seen on this upper picture, the square section of the bar helps stabilizing the tool on the tool rest of the lathe.
http://www.labellenote.fr/photo/gal_...ge_profond.jpg
You can see that here, it is a version with a long (maybe tool long vs the section, I will have to shorten it) shaft and long handle for deep hollowing. I also have a shorter version.

