Robert Allison wrote:
Pat wrote:

A 5/8" hole through a 4" wide beam reduces the load capacity by 1/4.
Unless your beam is oversized you may damage it enough to cause it to
fail.


Please don't top post.

In addition, I would like to hear from the engineers in here about the
validity of the above statement. I do not believe it for a minute.
This is done quite often and I would be surprised to learn that it
compromises the integrity of the beam. Unless you meant to say by 1/4
of 1 percent.
It depends on more information than is provided here but the load
carrying capacity is decreased by AT LEAST 16% and it could be 25%. The
smart thing would be to not drill this hole.

Boden, PE


"MiamiCuse" wrote in message
...

I need to drill a 5/8" diameter hole through a laminated beam that is
16" deep. This beam is sitting 10 feet above the floor across a room
support part of the roof. So I will be standing on a bench drilling
from below pushing the drill up.

I need this hole to be perfectly vertical as I will be passing a rod
through for a ceiling fan.

I know in the past when I had to drill through something much thinner
like a 2x4, I often end up with a slanted hole.

What can I do to ensure my drill is perfectly vertical?

I cannot afford to make a mistake and redrill.

Thanks,

MC