It's Instructables Build Night at Omaha Maker Group! As we got started, we realized that the A/C venting in our meeting room was undersized and we needed to add a new diffuser. And that required a ceiling tile with a large hole in it. Thankfully, this month's Build Night was presented by Dremel, and their rotary and Multi Max tools would be perfect for just such a task.

We thought it would be helpful to compare the process between the rotary tool and the Multi Max.

Step 1: Mark Your Tile

Before we get started with either tool, it's important to know what we're cutting. Based on where the duct would be located, we marked the ceiling tile with the position for the diffuser. This hole will be around 18" in diameter.

Step 2: Part 1 - Multi Max

We started with the Multi Max to cut the hole. In our experience, we knew the Multi Max did a great job at straight-line cutting. We weren't sure about curves. As you can see in the second photo, the size of the blade tended to make it hard to go around the curves.

Step 3: Straight Cuts With Multi Max

We cut a straight line across the middle of the circle using the Multi Max, which was easy and clean to do. We then cut pie-shaped wedges through half of the circle. The result was a half of a circle cut, but with faceted edges instead of a nice smooth curve.

Step 4: Part 2 - the Rotary Tool

We switched over to the rotary tool, equipped with the rotary cutting bit and the router/cutting foot. The resulting cut was smooth. But the rotary tool also managed to kick up quite a bit of dust, resulting in a messy work space. And the rotary tool required a LOT of control to ensure that the cutting bit stayed close to our desired path.

Step 5: Conclusion

For this project, we really found out that the Multi Max, with it's half-moon cutting blade, made excellent straight cuts with minimal dust while the rotary tool made excellent free-form cuts with smooth edges but with a lot of dust.

If we had to do it all over again, we would try the Multi Max with a narrow straight blade. Although we could not test that here, we feel like this would be the best solution.