BETAC-T wrote:
I have an old house with wood lath and plaster walls, and I need to cut out
a lot holes in the walls for light switches, electrical outlet receptacles,
etc.

Here is what I am doing now, and here is what the problem is:

I am just cutting them out by hand, one-by-one, using hand-held wallboard
saws, etc. The problem is that it is hard to keep the underlying wood lath
from vibrating and causing a wider area of plaster to crack and break out.
I have tried making sure each hole is adjacent to one of the studs so at
least one side of the hole has wood lath that is nailed down to the adjacent
stud. And, I have tried being very careful, cutting out a little, reaching
in to hold the rest of the wood lath stable, and then carefully cutting the
wood lath. But it is still a mess, doesn't work very well, and takes a long
time for each hole.

I don't think using any kind of powered reciprocating saw or saws-all would
help and probably would only make the lath vibrate more and damage a wider
area of plaster than using the by-hand method.

The problem seems to be the reciprocating action of the saws, so I keep
thinking there ought to be some kind of small circular saw that could be
used and plunged into the wall to cut the lath without vibrating it back and
forth. But I don't have, and haven't seen, a circular-type saw that would
be small enough to do this.

I have thought about buying one of those drill bits that supposedly can saw
sideways to cut holes in walls (which I saw on TV), but I haven't found
anything like that in any stores and I have a hunch they don't work anyway
(which is probably why they are only on TV).

So what the heck do professional electricians do? I keep thinking they must
have a tool or know of a trick to make this easy, especially since they
don't want to damage their customers' walls when putting in new outlets,
etc.

Any ideas? Thanks.

Looks like you've been getting some very good advice so far. If it
makes you feel any better, my wife is good at cutting holes in lath
and plaster for electric boxes. When I re-wire old houses that have
lath and plaster, all I have to do is mark where I want a box and she
goes at it. I go to the basement and run the circuits, drill holes in
the sill plate where the boxes are going to be and stuff the cable up
into the hole. By that time she's done cutting in the holes and all I
have to do is reach in and pull out the wire.

The moral to the story is that brute force does not apply when cutting
holes in lath and plaster. Easy does it. Use sharp tools. Let the
tool do the work. Buy a couple of saws if you have to, as plaster
will dull a saw blade quick.

The trick to cutting the lath, as others have mentioned, is to _remove
the plaster first_. The trick to removing the plaster is to _score_
it first. Once the lath is exposed one can usually reach in with a
pair of lineman's pliers and grab the middle lath to hold it still
while cutting the lath. Sometimes needlenose pliers work better, or
cut out some of the lath so the lineman's pliers will fit. Go easy
towards the end of the cut. Cut as far as you have to in the upper
and lower laths, on both sides, then just snap off the lath with the
lineman's pliers.

Again, easy does it, start out slow, speed will come with practice.