See above post dated: Jul 27, 11:39 pm. Essentially, I agree with
your post, but I also understand that every single top is not
engineered the same, making it impossible to think every installation
is exactly the same. I do understand the point about Corian being
Corian, though.

If I am understanding him correctly, and I might not, he has something
that is specifically designed/engineered and intended to be installed
in this manner. It may take into account the heat shielding (as
opposed to a heatsink which delibertately draws heat) into its design,
and so therefore be designed to be installed as per their own supplied
instructions.

nospam wrote: There is a bracket that is screwed to each side, and
then you drop
in the cooktop and it snaps into it. The counter is 1 1/2" thick.

Leave it to Gaggenau to invent something new and completely
unnecessary

If his instructions say to screw it into the sides, that is what they
say. Apparently he read them. If this is the manufacturer's preferred
or recommended or required way of installation, so be it. We know they
do not take into all types of countertops, and probably have some great
language in there excusing them from the process if you screw something
up while following their instructions.

Without being familiar with this brand of top and having no access to
the actual appliance, the Gaggenau, I am not ready to be as decisive as
Rob.

I am not saying he is wrong by any means, but we obviously have some
different experiences behind us on this issue. With that kind of
thickness, I have had no problems using screws with a predrilled hole.

My installer uses machine screws, and drills and taps as needed. His
other weapon is using a helicoil , and is best described by Ken
Dolph, who has written extensively on the issue of practical mechanical
fastening and Corian:

A helicoil looks like a spring. They are often used by mechanics to rethread stripped bolt holes. They are availible at most good auto part stores. Sometimes they will have clones as Helicoil is a brand name. They are used in industry to give soft materials an ability to hold machine threads. The common machine screw applies 90% of its force to the first thread. The Helicoil balances the force applying it more evenly across all threads. This reduces stripping.

Helicoils come in kits. You buy them by the size screw you wish to use.
The kit contains the proper size drill, a tap, and an installation
tool. You drill and tap your piece then scres in this spring like
thing. If it is a through hole you break offthe installation tab. They
are not cheap but in Corian they are the only way to go. Brass inserts
are useless.

So another point of view. Note that we are back to the drill and tap
mindset. It is important to understand that in context this is meant
as a "once or twice" type thing, not as a regular and routine way of
installation. He only uses mechanical attachment as a last choice. My
guy simply glues the crap out of everything.

Not trying in any way to start a flamewar here, but there is always
more than one opinion and more than one way to do something.

Robert