well, this week, plumbing and electrical rough in is starting. That means
drilling big holes through floors - big like in 3-4" diameter. At a 'normal'
construction site, you'd just toss a hole saw into your power drill, and its
easy. At THIS jobsite, a brace and bit has been filling in for the power drill,
so I figured I'd give it a try.
Bottom line: it works, but its slow, and a bit of a PITA. Hole saws are not
meant to be accurate. The twist bit in the center acts as a basic "keep it from
drifting all over the place" anchor, but with a power drill, the saw part
establishes a kerf pretty quick, and the blade them follows the kerf. This
doesn't happen with the brace. The twist drill is fine as "put it where you want
the center of the hole to be" guide, but once the saw blade hits, the inherent
wobbling of a brace comes into play, and the center hole tends to ream out a
bit. This means that the saw isn't making a nice clean kerf, but is making more
of a round trench. With care, this does eventually settle down into a cleaner
cut. In all honesty, as I recall, this is more r less how hole saws always work,
but when using a power drill, a couple ten revolutions while the blade gets
settled doesn't really matter.
Once the kerf is established, things stay touch. A 3" hole is actually cutting
about 7" of material. a 4" hole is cutting 12 1/2+ inches. That means that you
need to generate a lot of push to keep the blade moving. And the teeth tend to
clog fairly quickly. I'm guessing that with a power drill, the teeth tend to
clear by throwing the swarf out the side with centrifugal force. This doesn't
happen with a brace. Of course, there is no lead screw to pull the saw through
the stock, so you have top apply some pressure, but only a little - if you push
to hard, the teeth clog instantly.
I found that the best method was to use very light pressure, and not rely on the
center bit as more than a very rough placement guide. By starting at a very
slight angle, it was easier to get a kerf established because the swarf could be
dropped in the "high" part of the circle. constant blowing away of the swarf and
a slow rotation of the high spot let the bit get started. Once there was a kerf
established, I tried squaring the cut, but the bit clogged pretty quickly, so I
kept the rotating angle all the way through. I still had to remove the bit and
clear the teeth every 8-10 rotations. Slow going, but possible.
HAND SAWING PT
Pressure treated limber is great for ground or concrete contact, but it is WET.
That means it is soft and spongy. There is something about cutting it by hand
that just isn't easy. No matter what I did, the saw would bind up. 2x4s crosscut
OK, but anything bigger - 2x6, 2x8, 2x10, or 2x12, would bind. I didn't have
this problem with 'normal' 2x stock so it must have been something with the PT.
My guess is the high moisture content just caused extra drag. I'm using a 10
point crosscut saw, but its got a fairly narrow kerf in relation to blade
thickness, so the friction idea makes sense. Fortunately, other than cutting
stringers, I didn't have to deal with much PT. Cutting 4 steps worth of stringer
(10.75 tread, 7.375 rise) took about an hour (I had to cut 3 of them). this is
the first time that cutting the stringers took longer than laying them out....
The next big task is going to be ripping about 180 lineal feet of 2x4 into
1.5x2" stock for nailers. I may take this back to the home shop and just run
them through the table saw.
Hopefully, I'll be ready for rough in inspection on the 22nd. Then all I need is
insulation, wall cover, and occupancy permit....
-J
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