I suppose a home made grinder of any type is only as safe as it's
construction allows it to be. In other words, I should probably leave this
one alone! LOL
However it looks like a decent idea for building an inexpensive mini
surface grinder. The plans are at: http://www.dm.net/~lughaid/vest.htm
The pictures on the web page are too small to be of much use, but if you
save them to your computer, they can be enlarged to show the detail.