Is there anything a rotary tool can do that a oscillating multi-tool can't?

Question

I've got a decent chunk of change to spend on tools, and after cleaning the corrosion off of 96 battery terminals with scouring pads last week, I couldn't help but to think that a rotary tool (e.g. a RotoZip or a traditional Dremel) or oscillating tool (i.e. Fein MultiMaster) would make the job a lot easier. After thinking about it, I figured the oscillating tool would probably be better at the job than a rotary tool... seems a lot safer, too.

I struggled to think of something that a rotary tool would be better at, and the only things that I could come up with is drilling into tile/granite and cleaning other miscellaneous holes out (since a drum-shaped attachment would be perfect for that type of job.)

Anyways, other than drilling/cleaning out holes, are there any jobs that a rotary tool would be superior to a oscillating tool for?

Answer 1

A few things I've done/do with my rotary tool that can't be done with a oscillating tool:

• Etching numbers/letters with a diamond point (in very hard materials; such as marking serial number/ownership on a bicycle frame or tool).
• Polishing; many rotary attachments are made for polishing fine items.
• Routing. There are several router bit setups for roto-zips and dremels for doing very fine (i.e. gingerbread) work.
• Curved work, such as fitting tile or wooden flooring around a small curved spot.

Overall, the oscillators have their uses, and replace other tools, but the blades can be hideously expensive. The bits can be cheaper for a rotary tool, and sometimes they're just better suited for a job -- cutting holes in drywall to fit an electrical box is one great example of a task where you can do it by hand, you can do it with an oscillator or even a reciprocating saw, but once you do it with a rotozip and the right bit you're just going to hate doing it any other way.

Answer 2

I've only used an oscillating tool a few times (it was someone else's ... can't remember the maker, but I don't think it was Fein), and I do own a rotary cutter (RotoZip), and a few Dremel rotary tools, but they're smaller models for hobby work, not construction. The RotoZip is closer in spec to the Dremel Tri Multi-Tool from what I can find (it's on their website as the 'Dremel Trio', not filed under 'rotary tools', which tend to be more for finer / hobby type work, rather than construction). My take on them:

1. A rotary tool will have to remove more material, as the bits are at least 1/8" thick. This means that they'll generate more dust in the process.
2. The oscilating tools need space on the side to work. They're best when coming in from the edge, rather than being plunged in to make a cut. They have a sort of almost circular blade for plunging in, but it's only really useful if you're going to be making a cut that's at least as wide as the blade (3-4", depending on the one)
3. The nature of the oscilating tool means that it's going to hold a straight line better than a rotary tool. This might be good or bad, depending on what type of cut you're trying to make.
4. Because of how the blade mounts to an oscillating tool, it can cut very close to an obstruction ... so you can use 'em for trimming a door jamb so you can slide tile or other flooring under it. You can't do this easily with a rotary tool.
5. If for some reason you need to only cut down to a specific depth, you can adjust the cutting bit of the RotoZip within reason, and if if other rotary tools couldn't do it, you'd be able to use something to set the proper gap. I don't think it would be possible (or at least not easily) to do the same thing with the oscillating tool ... you really don't want to bring the head all the way down to the surface of what you're cutting.
6. The rotary cutters work great for cutting large circles in drywall, or in cement backer board when laying tile. For the actual tile cutting, if I can, I prefer a wet saw, but the rotary tools work fine for punching a hole in the middle of large tiles, to get around the pipes for a radiator or the showerhead if it's not right at the edge. (more common if you're using 12' tiles). I have no idea if oscillating tools are rated for tile cutting, and even if they are, they're going to have problems with curves or even making small square holes.
7. The rotary cutters work pretty well for cutting holes for work boxes ... but for drywall, a drywall saw works almost as clean and fast, and doesn't need to be plugged in. For putting new work boxes in plaster, on the other hand, they're great (just make sure you know which bits to use ... I killed a drywall bit cutting one the hole for one box). An oscillating tool might be able to do it; it could get the longer edge, but it might not be able to do the shorter sides cleanly.
8. The nature of the rotary cutters mean they work pretty well for enlarging holes that were cut too small. You won't get as clean of an edge as if you had used the proper sized hole-saw bit, but if you're dealing with large sheet goods, it's often easier than trying to conort yourself while holding a scroll saw. (especially so if you're cutting something that's already installed).

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If I guessed wrong on which Dremel you were looking at ... the smaller Dremel rotary tools have lots of uses, which is why I have more than one, but they tend to be more for hobby stuff, or prep work (like cleaning battery terminals) than construction-type tasks.

Answer 3

I recently purchased a Dremel MultiMax specifically for doing plunge cuts, as well as sanding panel doors and window frames.

I have already used the oscillating saw blade for plunge cutting into plywood subfloors and I love it (I'm re-insulating the floor space in my bay windows). I have also used the oscillating saw for straight cutting on kitchen drawers and it is so easy. You can clearly see where you are cutting and the blade thickness is minimal. The Dremel MultiMax is also quite light, yet sturdy.

One of the big advantages with using an oscillating tool for cutting wood is the reduction in saw dust; all the dust falls straight down instead of being spewed all over the place with a rotary saw. I have just finished cutting some cabinet drawers and did it in my kitchen; the clean up was so easy in comparison with a jig saw or circular saw.