On Fri, 12 Mar 2010 19:06:59 -0800, "LDosser"
wrote:

wrote in message
.. .
On Fri, 12 Mar 2010 00:29:51 -0800, "LDosser"
wrote:



On re-reading, it appears you are correct and I am wrong. I'd pull the
plywood!
You'd pull 1 1/2 inches of glued and screwed plywood? Destroying both
the plywood and the joists?????..

It took me just over an hour to manufacture the tool and do the job.
With no damage to the structure.


Your Original Post:

[I need to drill through 6 2X8 joists which are accessible only from
the one side. They are spaced 2 feet on centers. (need to pull cable
across to the center of the floor). The joists are sitting directly on
concrete, and the decking is 1 1/2" (you read that right) plywood.]

See anything about plywood Glued to Joists there? See anything about $50/yd
Carpet there?
I also didn't ( i think) mention that the 2X8 joists were stacked,
giving 15 inches, more or less, of height.

No, but did you see anything that indicated I was entertaining ANY
OTHER solution, other than drilling? I just asked WHICH KIND IF BIT
would do the job with the least resistance /power usage since I was
pretty well committed to drilling with a 12 foot extention of some
sort.
(I also didn't ( i think) mention that the 2X8 joists were stacked,
giving 15 inches, more or less, of height.)

Anything that jammed up would make it difficult and retrieving a
damaged bit or extension would not be an easy chore.

NOBODY addressed that question. 1 1/2" auger bits are not common. They
also tend to drill faster, requiring more driving torque. Spade bits I
found to be problematic in break-through as they are not self guiding.
The forstner IS self guiding and self clearing and it ends up, also
requires the lowest drive torque as it shaves the wood off in thin
layers, and does not bind - even if the hole comes out tight against,
or impinging on the joist or plywood decking.