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This kit gives you everything you need to get started using Bosch and most other manufacturers attachments! Click image to enlarge

Bosch MX25EK-21 Multi-X Oscillating Tool Kit

A versatile tool and a plethora (bunch) of attachments!

Text, photos and video by Tom Hintz

Posted - 4-12-2011

For a long time there was really only one game in town when it came a quality, hand-held oscillating tool. Everyone knew that market-cornering singularity could not go on forever and sure enough, here comes Bosch with their Bosch MX25EK-21 Multi-X Oscillating Tool complete with the imprint of their world-class engineering and manufacturing capacities. The oscillating tool world will be a one horse race no more.

The Basics

The Bosch MX25EK-21 Multi-X Oscillating Tool is a handheld 120V-powered oscillating tool that uses a multitude of cutting, sanding and grinding attachments made by Bosch and others. What makes these tools effective is moving those attachments through a small arc very quickly. I know that sounds simple enough but making that motion at the speeds that the Bosch MX25EK-21 Multi-X Oscillating Tool is capable of and doing that reliably borders on a miracle. Consider that the Bosch MX25EK-21 Multi-X Oscillating Tool moves the attachments through a 2.8-degree arc, 1.4-degrees left and right. To make the attachments effective they cycle through that arc 8000 to 20000 times per minute. Try that with your sanding block!

The box of attachments (left) that comes with the tool is plenty to get you started. The available selection of Bosch attachments (right) is sure to grow but you can also use attachments from most competing manufacturers. Click images to enlarge

Another important factor is that Bosch also developed something called OIS (Oscillating Tool System). The important thing about this OIS system is that it lets you use oscillating tools from just about all of the known manufacturers of oscillating tools. That means that no matter where you work with the Bosch MX25EK-21 Multi-X Oscillating Tool, attachments that you need for the job are probably not far away.
The Bosch MX25EK-21 Multi-X Oscillating Tool reviewed here comes with a canvas carry bag and a nice box with 6 attachments including three packs of sandpaper triangles. Later in this review we’ll look at part of the huge range of tooling Bosch has available for this tool.

Power Controlled

The Bosch MX25EK-21 Multi-X Oscillating Tool is powered by a 2.5-Amp motor to handle contractor-tough jobs as well as everyday home shop needs. The motor has the Bosch Constant Response™ Circuitry that helps it maintain the selected speed as the loads vary. This is particularly handy on this tool because of the huge range of attachments that it can use. For the more hyper professional users Bosch includes flush-fitting covers on either side of the tool that allow checking or changing brushes.

To further control the available power Bosch added a speed control. A dial in the heel of the Bosch MX25EK-21 Multi-X Oscillating Tool lets the user select the best speed for the job. The dial has number markings that indicate – 1 = 8,000 RPM, 2 = 10,400 RPM (oscillations per minute), 3 = 12,800 RPM, 4 = 15,200 RPM, 5 = 17,600 RPM and 6 = 20,000 RPM. And for those who think a speed control should always be set on kill, Bosch supplies a chart in the instruction manual with suggested speeds for many common jobs. The recessed speed control dial is out of the way to avoid accidentally changing speeds during use. A simple slider ON/OFF switch located on top of the grip area handles the stop/start stuff.

The grip area (left) around the motor is slim and comfortable to the hand. The speed control dial and swivel cord (right) can be seen from the rear of the tool. Click images to enlarge

The Body

The grip area that surrounds the motor on the Bosch MX25EK-21 Multi-X Oscillating Tool is surprisingly small in diameter because of the Bosch motor technology. That space saving design allowed Bosch to create an ergonomic grip that is comfortable to the hand. They added rubber overmolds in key areas to further enhance grip, user comfort and to insure control to make the Bosch MX25EK-21 Multi-X Oscillating Tool easier to use overall as well as accurate.

Even the gear drive up front is slender to allow using the Bosch MX25EK-21 Multi-X Oscillating Tool in surprisingly tight corners. To further enhance close-quarters usability Bosch added a Ball-Joint Cord Swivel in the butt end of the tool that gives you even freedom of movement.

The gear housing at the front of the Bosch MX25EK-21 Multi-X Oscillating Tool that creates the arc motion is surprisingly trim. The 3.3-lb heft of the Bosch MX25EK-21 Multi-X Oscillating Tool is testament to the amount of metal used within that package to insure the durability of the gear section. Bosch has been building power tools for a long time and is no stranger to developing tough, dependable gear systems. While they were designing the gear system for the Bosch MX25EK-21 Multi-X Oscillating Tool they minimized vibration to a point I would not have thought possible in a tool that essentially shakes its cutter several thousand times per minute!

The gear case is covered with a rubber overmold that helps reduce oscillation-related sounds should the front of the Bosch MX25EK-21 Multi-X Oscillating Tool contact with the surrounding wood. To prevent the rubber material from marking up the wood Bosch even added two no-mar strips across the front of the Bosch MX25EK-21 Multi-X Oscillating Tool. It’s little touches like this that tells me that people who are familiar with woodworking were in on designing the Bosch MX25EK-21 Multi-X Oscillating Tool.

Attachments

Because you can mount the attachments at virtually any angle you can choose whether straight (left) or 90-degrees (right) to the tool is best for your job, or somewhere in between." Click images to enlarge

Bosch makes at least 12 different attachments for the Bosch MX25EK-21 Multi-X Oscillating Tool for everything from cutting to grinding, sanding and scraping. I suspect that more variations will be coming down the road. The attachments are driven by a plate with raised lugs that fit into notches in the attachment and then retained by a hex-head screw. A hex wrench for changing the attachments is included.

Bosch also includes another drive plate (#OSCAD1) with a slightly different lug pattern that let you use most attachments from oscillating tool competitors. That means that you will never be far from essential attachments pretty much wherever you are as long as the area is relatively civilized.

The attachments can be installed in many different angles around the circular drive plate so that you can install the attachment for the best access, comfort or control for the job at hand. Because the tool does not rotate a heavy guard shield is not needed which affords the operator even more flexibility when installing the attachments.

Bosch even offers a dust attachment (available separately) that is designed to inhale dust through passages in the sanding pad. This attachment comes with adaptors to connect it to most common shop-vac hoses.

In the Shop

Just two of the cuts you can make with this tool are simple plunge cuts (left) to make a cutout or undercut trim (right) for installing a wooden or tile floor. Either is done very quickly with surprisingly clean cuts. Click images to enlarge

The first time I turned the Bosch MX25EK-21 Multi-X Oscillating Tool on I thought that perhaps I had gotten a dud as there was virtually no vibration. I knew that it was running but it didn’t seem to be doing anything beyond emitting a muted buzzing sound. I installed one of the larger saw attachments and turned it on again. This time I could feel the attachment vibrating and when I touched it to wood, it cut! It still amazes me that such a small arc can actually cut, grind or sand but that is exactly what happens with the Bosch MX25EK-21 Multi-X Oscillating Tool.

Using the Bosch MX25EK-21 Multi-X Oscillating Tool is easy in terms of effort and control. The grip area gives you good control and the lack of vibrations means that the tool is not trying to steer itself. Even after using the Bosch MX25EK-21 Multi-X Oscillating Tool for 20 or 30 minutes I was not feeling tired or like I was straining to maintain control.

The range of attachments means that you can tailor the Bosch MX25EK-21 Multi-X Oscillating Tool for the job at hand so it is most effective. Changing the attachments is a breeze but even more important is being able to align the attachments in whatever orientation best fits what you are doing. Very often having an attachment aimed to the side is much easier to control and that means that you are more accurate.

Getting into corners and small areas is the part of the world for which the Bosch MX25EK-21 Multi-X Oscillating Tool was designed. You aren’t going to sand the entire living room floor with the Bosch MX25EK-21 Multi-X Oscillating Tool but you can clean up the corners and small areas that traditional sanders can’t touch and do it quickly. Another time and labor saver is being able to do that kind of work without damaging the surrounding woodwork. Working with raised panel doors and many other project types that present corners or small areas will all benefit from having a Bosch MX25EK-21 Multi-X Oscillating Tool in the shop.

The speed control and the chart in the instruction manual are worth getting used to. I followed the suggested speeds for several uses and the Bosch MX25EK-21 Multi-X Oscillating Tool performed very well. I tried going higher and lower with the speed control and the recommended speeds always seemed to work best. I know that the folks at Bosch know what they are doing, I was just checking.

Conclusions

There are precious few projects in any woodworking shop (or DIY’er honey-do list) that do not have several opportunities for the Bosch MX25EK-21 Multi-X Oscillating Tool to make your life easier and your projects look better.

With a street price of just $159.99 (4-12-2011) for the Bosch MX25EK-21 Multi-X Oscillating Tool kit shown in this review you can bring this wide-ranging capability to your shop for considerably less than I was anticipating. We can blow $150 on way less productive things and too many of us already have. Buying the Bosch MX25EK-21 Multi-X Oscillating Tool has lots of benefits for you and your projects and the durability means that those benefits will keep coming for many years to come.

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