"engsol" wrote in message
...
I'm replacing my knotmeter with a new unit. The hitch is that the
old sensor required a 1 3/4" hole in the hull, but the new sensor
requires a 2" hole.

Ever try to use a hole saw without something for the pilot drill to
bite into? Very difficult, and certain to make gouge marks where
you'd prefer there be none..

My solution was to nest a 1 3/4" hole saw with the 2" hole saw.
The smaller hole saw now becomes the "guide" for the larger.
After well started, the inner hole saw is removed. Worked perfectly.

I bet I'm the only person in the world who didn't know this trick, but
just in case not, I thought I'd pass it along.
Norm B

Not sure of the exact nature of the body of material you were drilling, but
I have often had to redrill or saw hut a hole that is offset fromt he
original hole. I simpley cut a plug to fit the hole and glued it in place.
Then after it was set I redrilled the hole.

Your trick of nesting a saw within a saw is one I have never heard of
before, but it makes perfect sense. I will try and remember that one,
because I have had to increase the size of a knockout hole in an electrical
communications J-Box in the past. Your trick would work perfectly for this
application.
--
Bob La Londe
http://www.YumaBassMan.com