Oscillating multi-tools are everywhere in the shop. They cut, sand, scrape, and grout. They are one of the most versatile tools you can own.
But the dust port on an oscillating tool is small. Usually 28mm to 32mm outer diameter. And the tool is often used in tight spaces where a vac hose gets in the way.
So does connecting a shop vac to an oscillating tool actually help?
When It Helps
Sanding with an oscillating tool is the main case where dust collection matters. When you use a sanding pad attachment, the tool generates fine dust similar to a random orbit sander. A connected shop vac captures most of it.
Cutting drywall also produces a lot of dust. If you are cutting drywall patches, connecting a vac makes a big difference in how much dust you breathe and how much cleanup you need after.
Wood cutting with a plunge cut blade is somewhere in between. The cut is fast and focused, so less total dust than sanding. But fine wood dust is still worth capturing.
When It Does Not Help Much
Scraping with a carbide blade generates almost no dust. There is nothing to capture.
Grout removal generates grit that falls downward. The port is on the back of the tool, not near the grout line. A vac captures very little of the grout dust. Wear a respirator for grout work instead.
Flush cutting with a wood blade in a tight corner, the hose gets in the way and the port is not near the cut. In this case, skip the hose and just wear a mask.
Port Sizes by Brand
| Brand | Port OD | Key Models |
|---|---|---|
| Milwaukee M18 FUEL | 32mm | 2836-20 |
| Milwaukee M12 | 28mm | 2457-20 |
| DeWalt 20V MAX | 32mm | DCS355B |
| Makita LXT 18V | 36mm | XMT03Z, XMT04Z |
| Bosch 18V CORE | 35mm | GOP40-30B |
| Ryobi ONE+ | 32mm | PCL540B |
| Ridgid 18V | 32mm | R9020 |
| Worx 20V | 32mm | WX550L |
How to Connect a Vac
Find the adapter that goes from your tool's port size to your shop vac hose. The port is almost always at the rear of the tool, near the blade clamp.
For sanding sessions, connect the vac and run it the whole time. The suction is strong enough to pull dust through the sanding pad if you are using a vented pad attachment. Not all sanding pads vent to the port. Check your pad's packaging.
For cutting sessions, connect the vac if the hose will not get in the way of the cut. If you are making long cuts down a wall, a vac helps. If you are making three short cuts in a corner, the hose is more trouble than it is worth.
Best Vac for an Oscillating Tool
A small shop vac works well. The oscillating tool port is tiny, so you do not need a high-volume collector. Even a compact 2.5-gallon shop vac provides enough suction through the small port.
For sanding sessions longer than 10 minutes, use a vac with a HEPA filter. Fine sanding dust is the most dangerous for your lungs. A standard paper filter lets the smallest particles through.