"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 4.170...
Ignoramus32423 fired this
volley in
:

Lloyd, I used those holes to mount TO-220 voltage regulator chips,
not
for anything structural. worked great!

They won't hold with temperature swings, Ig! Put a nut and
lockwasher on
the backside! Go with me on this... I've done many THOUSANDS of
semiconductors on heatsinks, and had both many successes, and every
sort of
failure you could count -- from taking shortcuts. Shortcuts just
never
work in a temperature-cycling environment.

Lloyd

How careful you need to be depends on how close to the rating you are
operating. TO-220s aren't fussy at a few Watts but need thermal
analysis as you approach 20W.

http://www.diyparadiso.com/component...pnotes0899.pdf
"Belleville washers, or compression washers are generally considered
the
preferred method of attachment to a heat sink."

-jsw