-MIKE- wrote:

They are sold by others, but are very expensive.

Like most HF copies of otherwise expensive tools, I thought these
would be lousy. But they are higher quality than I expected. You'll
see them a lot in the electrical and sheet metal industries where
they after have to enlarge holes in metal.

I use them often to create holes where there are no knock-outs in electrical
boxes. The work like a charm. They are so cheap that when I wear one out,
I just go get another. I've used them on sheet metal, on thicker steel - no
problem.

--

-Mike-