Anyone have experience with these oscillating tools?
Seems like all the manufacturers have one now, Dremel, Ridgid, Makita, Dewalt, Milwaukee....

I will be cutting in boxes in plaster with metal lathe.

TIA

They'll go through the plaster just fine, but once they reach the metal lath they'll vibrate it something fierce.
If you can use one to get through the plaster and then cut the metal lath with your cutters you should end up with a job that won't need any wall repairs.

What blade do you use? I've seen blades rated for both wood and metal which I thought would do the plaster as well. Plus there are blades for tile grout, seems like they might work too.

These have been around for years...

And have gone off-patent.

What Fein had charged pretty for simply collapsed in price.

Harbor Freight is pitching an Asian import for peanuts.

The action -- for the manufacturers -- is in the blades.

Even Fein's don't last.

Their metal cutting ability does not extend to drywall screws, BTW. Even a single such attempt will ruin a $15 blade.

They are ideal for old work. You'll see them slipping into the frame of This Old House, Ask This Old House, and in the tool kits of every DIY Network host -- if you watch long enough.

For me, they are the only game in town for plunge cutting old work lumber.

My first usage, all those years ago, had the GC dropping his jaw. He'd hoped to have buried me with some plywood sheathing. No dice.

Multi-masters even change my build sequence. I use fewer 3/0 rings now - going square instead.

For new buyers, the issue is blades expense. You'll have to do your own homework: everything is changing with the end of Fein's patent wall.

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I don't work in old plaster. But, if I did, I'd never use a vibration tool. >>> Crack-city!

You are much better off using the ancient classic: the beater. This is well exampled in one episode of Ask This Old House: a wise journeyman is installing CAT5 cables to establish an intercom in an ancient house. (circa 1895)

He gently taps his beater along the line of incission. Then he cleans it up (the plaster skim zone) without vibration. [Off camera -- assume razor knife and beater tapping.]

Next he gets at the support grid. His Kleins (dykes) (2000 series, curved) make short work of that.

More gentle craft work leaves the cavity suitable.

In his case, a LV mount is used to skirt around a totally foreseeable stud -- part way into his work zone.

Routing cable in those old balloon construction homes is a total snap. There is no insulation in the way, nor firestops, nor diagonals.

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In sum: they are great tools. They don't cut cheap -- the blades go dull very fast. This is manufactured in so as to keep you spending, spending, spending.

Generally, it's not possible to use generic blades for these power tools. Design patents are still holding off rationalization.

The blades don't lend themselves to field sharpening, either.

Be mindful of tear-out at the tool arbor. This focus of force and vibration is built as a mechanical fuse/ money spinner. Expect your most expensive tool heads to fail at the arbor when you least expect it.

So watch your force level.

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Lastly, the el cheapo imports have low power -- and low rates in application. If you have to eat their limitations, then they stop looking so cheap.

The original Fein is still the Duesy. In comes with a very nice (as in expensive) tool case with all of the trimmings. That's not a small factor for a tool that has gazillion working heads. (A multi-master is the exact opposite of a Skilsaw.)

You might want to look into Sortimo, too.

http://www.sortimo.com/Cases-and-Boxes.47.0.html

These are very pricy... and have been adopted wholesale by the Hollywood craftsmen. The Fein case is dimensioned close to the Sortimo world, BTW.

In the same vein you might desire FastCap's Kaizen Foam.

http://www.fastcap.com/estore/pc/Kaizen-Foam-p13435.htm

It has universal application for anyone who depends upon tools -- and getting to them quickly. With this product you can make your own versions of Sortimo's cases.

You'll want a fast PC to wander around FastCap's website. It's overrun with java scripts -- all of the bells and whistles.

You'll recognize many of FastCap's stuff popping up on Ask This Old House and DIY Network. It's exploding across America.

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When you buy your oscillator, think ahead to all of the tool heads that it travels with. Without them, you've cheated yourself.

These things have been around the medical business for years since originally being designed as bone saws. Their claim to fame has been that they will cut something solid like bone but will just harmlessly wiggle something like soft tissue...and they're easy to control. If the blade suddenly gets caught in the cut you just let the tool wiggle as it stops whereas something like a sawzall will start bouncing the whole tool around.
Any blade with teeth will cut the plaster (it's quite similar to bone) but if the teeth grab the metal lath it will grab it and start shaking it around. You can use it (carefully) with wood lath because the wood will cut similarly to the plaster itself; but it's a whole lot trickier to do the same cut if you have metal lath.
I would suggest practicing somewhere out of the way like an inside wall of a closet before using it on a finished wall. You might even want to make a sample piece of wall to play around with using some scrap metal lath and plaster patching compound.

It is dusty but a side grinder will get into stuff like that. They have a problem if you hit wood lath tho.

I see a lot of 'thinking' here that is not backed by experience.

Cutting stucco, or old-style plaster & lath is a challenge because it is a mix of masonry (plaster) and steel wire.

The plaster readily becomes dust, flying everywhere and coating everything. The wire tends to grab on saw teeth, transmitting force throughout the wall - leading to the need to repair extensive damage far away from the work site. It's pretty hard to make a patch that won't show in the right light.

Reciprocating saws - Saws-it-alls and saber saws - tend to have their blade teeth catch on the wires. This makes a large part of the wall vibrate back and forth, and cracks appear everywhere.

A circulating saw will work, but the material is death to blades, and dust is thrown everywhere.

Router-type tools, like the RotoZip, work, but dust is an issue, and they're not as controllable as I like. I also have issues with bits breaking, short bit life, and feeling what you're cutting into.

Using an angle grinder avoids the shaking, but the dust problem is still very real. Extensive preparation - tenting, air filtration, vacuuming, lighting, and PPE- is needed. A grinder will cut wood, but you'll smell burning wood.

Frankly, the Fein Multi-Master (and its' clones) stands head and shoulders over the rest. The extremely rapid oscillations of the blade, and the very fine teeth on the blades, make for a controlled, catch-free cut. You can readily feel when you hit different materials. (Since I often find cables right up against the wall, this is important).

I use the moon-shaped carbide grit blade for cutting stucco and plaster. It has no problems with cutting the metal wire. Dust created does not become airborne- it usually sits right on top of the blade as you cut, or falls straight to the floor.

Which brand to buy? I started a very contentious thread over at Fine Homebuliding's "Breaktime" forum, comparing the Fein to the $40 Harbor Freight clone. Look it up here: http://forums.finehomebuilding.com/.../fein-multimaster-vs-cheap-chinese-clone .

Some guys still do it the old-fashioned way, with chisels, punches, and snips. Unless there's wood to be cut, this way is still often the 'best.' Slow and tedious - but relatively clean and with less chance of damaging the wall around you.

Reno:
I had used a Fein 'loaner', and then bought a Rockwell. Yes, IMHO, the Fein is the Mercedes, but for my limited use, the Rockwell is OK.

Back in the days, a chisel & Kleins worked, along with patience. Diamond mesh was brutal.

Old houses with plaster/lathe is a large percentage of our business. If the house is empty, angle grinder is the only way to go, fast and neat. A bit different if occupied, like Reno said, lots of prep, tenting, and one guy to hold the shop vac close while the other guy cuts. The multi tool with the carbide blade does work, but does not last long especially in harder plasters. If the lathe is wood, we cut out the plaster first then gently saw the lathe with a drywall saw. It is very soft and cuts surprisingly easy. The lengthwise pieces can be snapped off with a pair of channel locks after the sides are cut to the desired break off point. We always try to be up against a wall stud, and remember to saw the lath on the side away from the stud first while it still has support. A tiny carbide bit finds the studs, and the holes it makes are easy to patch.

When my multi tool blades get smooth I cut more teeth in them on the band saw. They are only good for drywall after that though. I cut the new teeth all the way around on the straight blades, making them into sort of miniature crescent blades, makes for easy drywall cutting.

Just my $0.05 worth here (corrected for inflation).
I've dealt with older houses over here in the past with 1" x 5/8" timber lath and plaster walls.
You'd be suprised how much control a 4" angle grinder gives you with cutting wood and plaster with the right disc on it.
I've never struck a house yet that has steel laths, but I'm betting with a steel type disc, you could chew through both the plaster and the laths, as long as you have some sort of dust extraction system and a fire extinguisher in case there is dry/flammable stuff in the bottom of the wall cavity.
Although I've yet to set anything on fire with an angle grinder, if you're careful, it doesn't hurt to have things like that there, just in case.

You are right Trumpy, angle grinders are one of my most favorite tools, that's why I have over twelve of them at home and two on the truck (nice not having to constantly change wheels, just grab a different grinder). A diamond blade cuts the plaster, wood, metal no problem, just a little snipping and trimming in the corners. We cut into masonry walls with them as well and set flush mount steel boxes. The largest, most powerful shop vac you can fit in your truck with a clean filter is the best dust collection system I've found.

I used my rotozip with the dry diamond circular blade the other day to cut plaster.

I ended up purchasing the Dremel, seemed to have the best selection of blades. Tried it on one opening with the combo wood/metal blade and it worked OK but just too slow, so I went back to the old way of drilling a half inch hole on opposite corners then using a sawzall. High speed and slow feed made a nice cut with no cracking.

You can't beat the selection offered by Fein.

But, they're not cheap, not by a long shot.

Many of the new oscillators are weak -- and designed down so as to appeal to the average homeowner -- especially the housewife.

While they certainly work, they run at less than half the power of my Fein. (Fein makes even more powerful versions that are not currently receiving a marketing push. You can find them, from time to time, on eBay -- second hand.)

I've had mine for about nine-years. I liked it better when I was the only electrician out there with one.

To restate the obvious, its place is doing things that no other tool can do: plunge cutting into studs is at the top of my list.

I had a Dremel oscillating tool. It worked ok but you needed to use a hex (Allen) wrench to change the blades.
Then my van got broken into and one of the items they took was the Dremel. For a replacement I got a Porter-Cable.
It has a quick release so changing the blades doesn't require any tools.
Most all the brands of blades fit so I have a wide choice.
I went with the corded model.
I almost want to thank the punk that ripped off the Dremel. That's how much better I like the Porter-Cable.
I'm good with the Sawzall but the oscillating tool allows me to make detailed cuts that would have taken a long time to do with any other tool.
There are metal cutting blades that should work well for wire mesh.

I started with a dremel for light duty stuff. As soon as i needed a better tool for plunge cuts in 1.75 inches of wood i went directly for the fein. I like the dremel for close quarters stuff.

The Rockwell worked great for cutting right up to kickplates on my base cabinets. 3/4" oak. Yes, slow; but it worked great. I do not know of any other tool that would cut flush like that.

I played with a few blades, the best/easiest I found for what I was doing was the 'half-moon'.