Cutting a hole for a double-gang box into existing drywall is one of those tasks that sounds easy until you’re holding a drywall saw and realizing your lines are crooked. You’ve probably been there. You trace the box, you jab the saw in, and five minutes later, you have a hole that looks like it was chewed out by a caffeinated beaver. This is exactly why the electrical box cut out saw for oscillating multi tools exists. It basically turns a delicate surgical procedure into a "snap-and-go" operation.
I’ve seen pros try to do this with a standard plunge blade on their vibrating tool, and honestly, it’s a mess. You’re trying to hit four distinct lines perfectly without over-cutting the corners. It’s stressful. But these specialized square or rectangular blades—often called "box cutters" or "gang box blades"—attach right to your OMT (oscillating multi-tool) and punch out the exact dimensions of a standard plastic or metal work box in about ten seconds. No kidding. It’s satisfying in a way that’s hard to describe until you see that perfect rectangle of drywall just fall out.
The Mechanics of the Punch Cut
Standard blades move back and forth in a tiny arc. That’s great for flush cutting a door jamb. But for a square hole, you need four blades working in unison. These attachments feature a four-sided design with teeth specifically ground for gypsum board. When you press it against the wall, the oscillation transfers to all four edges simultaneously.
Most people don't realize that these blades aren't actually "saws" in the traditional sense; they are more like high-speed vibratory punches. Because the teeth are shallow, they don't create the massive cloud of dust you get with a hand saw or a spiral "Zip" tool. It’s cleaner. It’s faster. And most importantly, the hole is the right size every single time.
If you’re doing a kitchen remodel and adding six outlets for under-cabinet lighting, the time savings alone pays for the blade in about an hour. You aren't measuring four sides. You're measuring one center point or a single level line. That’s it.
Why Quality Varies So Much
You can go on Amazon or to a big-box store and find these for $10, or you can spend $50 on a professional version from a brand like Milwaukee, Southwire, or Saker. Does it matter? Yeah, it really does.
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Cheap blades tend to have "slop" in the mounting bracket. Since an electrical box cut out saw for oscillating multi tools relies on precise vibration, any wiggle in the interface means the energy doesn't reach the teeth. You end up just vibrating your hand while the wall stays intact. High-end blades use a thicker gauge of stainless steel or high-carbon steel. They also usually have a Universal Fit or Starlock interface that actually stays tight.
"The secret to a clean cut isn't just the blade; it's the RPM management of the tool itself," says veteran electrician Mark Walters. "If you run the tool at max speed, you risk scorching the drywall paper. You want a mid-range oscillation that lets the teeth bite without generating excessive heat."
Another thing: check the depth. Some of these blades are designed strictly for 1/2-inch drywall. If you’re working in an older home with 5/8-inch fire-rated board or, heaven forbid, lath and plaster, a cheap, shallow blade will fail you. It won't reach all the way through, leaving you to finish the cut with a utility knife anyway. That defeats the whole purpose.
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Single Gang vs. Double Gang
Most of the time, you'll want the single-gang version. It's the bread and butter of residential electrical work. But if you’re a pro, you need the double-gang blade too. Trying to "double up" a single-gang hole by moving the tool over rarely works perfectly. You end up with a weird ridge in the middle.
The Hidden Danger: Metal Studs and Wires
Here is the thing nobody tells you in the marketing videos. These blades are aggressive. If there is a 14/2 Romex cable tucked just behind the drywall where you’re cutting, a standard drywall saw might nick it. An oscillating box cutter will chew right through the insulation before you even realize you’ve hit it.
- Always use a non-contact voltage tester before you cut into a wall where you know wires are present.
- Depth control is your friend. Don't bury the tool.
- Check for studs. These blades are wide. If you’re right up against a 2x4, the blade will bounce off the wood and kick back at you.
Practical Tips for the Perfect Cut
Start by marking your center point. Use a small level to draw a single horizontal line. Many of these blades have a built-in "v-notch" or a center mark on the frame. Line that up.
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Don't push hard. Let the tool do the work. If you force it, the oscillation slows down, and you'll actually take longer to get through the wall. I like to start by touching the bottom edge of the blade to the wall first, then tilting it forward so the top edge makes contact. This "rolling" entry prevents the tool from jumping around on the surface of the drywall.
Once you’re through, pull the tool straight back. If the piece of drywall gets stuck inside the blade—which happens often—don't poke it out with your finger while the tool is on. I’ve seen some nasty cuts that way. Use a screwdriver or just tap the side of the blade.
Compatibility Issues
The "Universal" label is sometimes a lie. If you use a Bosch or Fein tool with a Starlock mount, a standard OIS (Oscillating Interface System) blade won't fit without an adapter. And adapters suck. They add vibration and length. If you have a Starlock tool, buy a Starlock-compatible box cutter. It’s worth the extra five bucks to keep your nerves from being fried by the extra vibration.
Is It Worth the Tool Bag Space?
If you’re a homeowner doing one outlet? Probably not. Just use a $5 hand saw. But if you're a DIYer tackling a basement finish, or a pro who does "old work" boxes daily, it's non-negotiable.
The accuracy is the real selling point. When you use a hand saw, the "ears" of the old-work box (the little plastic flaps that flip out to hold it to the drywall) need a solid surface to grab. If your hand-cut hole is too big or jagged, those ears have nothing to bite into. The box will always be loose. With an electrical box cut out saw for oscillating multi tools, the hole is so tight the box almost stays in place by friction alone. That makes for a professional finish that won't wiggle every time someone plugs in a vacuum.
Moving Forward With Your Project
To get started, you need to verify your tool's mounting system. Look at the "business end" of your multi-tool. If it has a star-shaped pattern with holes, you're likely in the OIS or Universal camp. If it looks like a 3D bottle cap, that's Starlock.
- Identify your box type. Ensure you are buying the blade that matches the "Old Work" (remodel) boxes you've purchased. Most are standard 2-3/8" x 3-3/4", but double-check.
- Clear the area. Use a stud finder to make sure you aren't about to plunge into a structural member.
- Practice on a scrap. If you have a piece of leftover drywall, do one test cut. It helps you get a feel for how much the tool wants to "walk" when you first start the cut.
- Manage the dust. Even though these are cleaner than circular saws, they still drop dust. A simple damp cloth or a vacuum nozzle held just below the cut will save you twenty minutes of cleanup later.
Once you have the right blade, mark your heights consistently across the room—usually 12 to 16 inches from the floor to the bottom of the box—and you'll be able to fly through the installation phase.