"Goedjn" wrote in message
...

I sectioned one using a new box cutter blade, about the sharpest blade you
can find these days. It was almost impossible to move it through smoothly
without lubrication. A soap solution was used and I got the smooth
surface
I need. But with the hole saw it didn't keep the teeth from grabbing
despite reversing the rotation. So I will try to sharpen some 3/4 copper
pipe as I mentioned unless I can find a 1" cork borer.


Why not use 1" EMT, if what you're after is a 1" hole?
Out of curiosity, what are you trying to make, anyway?

Used nominal 3/4" copper pipe to make the "corkborer" because it was closer
to the snug fit I needed.
You can see the final product at

http://img20.imagevenue.com/img.php?...CT0313AJPG.JPG


I'm making a device called an audio coupler, usually made from metal or hard
rubber. Want to see how the cellular version might work. The coupler is
used between a Sound Level Meter and the source of the sound and modifies
the sound so that the meter hears the sound as an ear might hear it. It's a
function of the geometry of the hole. That's really an oversimplified
description. There is a lot of audiometry literature on the subject, on the
"2cc Coupler", 2cc referring to the volume of the adult ear canal. Picture
of an earlier version being used to calibrate a headphone at

http://img105.imagevenue.com/img.php..._PICT0299A.JPG