Re: Hole Diameter for running cable

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"B Fuhrmann" <b-fuhrmann-usenet@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:12n06noahade58d@xxxxxxxxxxxxxxxxxxxxx
>
> "Robert Green" wrote in message ...
> >
> > You don't need to restore the joist strength for 2" holes.  Just keep
> > them away from the center 1/3 of the joist and at least 2" apart from
> > each other.  Also, stay near the vertical center of the joists.
>
> I have seen this posted several times and it could be misleading to the
> reader or it is wrong.
>
> By "center 1/3 of the joist", I am assuming that you really mean the
center
> 1/3 of the span where the stress is the most.

I assume we're talking about a joist like this with O representing a hole:

________________________________________________________


   O Here             O Not Here                O Here

                      O Definitely not here!
________________________________________________________

> The holes SHOULD be in the center 1/3 of the joist, measured across the
> width of the board.
> As others have pointed out that is where there is very little stress on
the
> board.
>
>
> ---- The origonal poster has also commented on knots being a problem.
This
> is for him.
> A lot depends on the condition of the knot and it's location.  A knot that
> is not loose or cracked is much less of a problem than a loose or cracked
> one.  The tight knot will still disrupt the stress pattern but much less.
> Knots that are towards the top of the joist are in compression.  I that
> location, they are less of a problem.
> A loose or cracked knot at the bottom edge of the joist is in tension and
is
> almost equivalent to a notch there.

There are knots on the top and bottom but I think I've mapped out a path
that avoids any knots that are on the bottom of the joist.  As you point
out, that's where a fault can produce the most structural weakness.

> For strengthening the areas that you are unsure of, I would recommend the
> spike plate material that is used in building truss framing.   It is
strong
> and does a good job of marying the stress to the area under it with many
> "nails".

That sounds like a good idea.  I am just not sure how easily I can punch a
2" hole in something like that.  I've got loads of plywood scraps, a hole
saw and lots of woodscrews.

--
Bobby G.