Flex 24V Cordless Die Grinder Review FX3211-Z

Flex Cordless Die Grinder

Easily Shape Metal, Wood, and Stone with the Flex 24V Die Grinder

A die grinder is much more than just a standard handheld rotary tool. They’re a powerful, invaluable tool for metalworkers and machinists. That raw power combined with the relative niche-iness of the tool is why you don’t see a ton of cordless options out there – but they do exist. The Flex FX3211 Die Grinder is making its debut on their 24V platform, and from the look of things, it means business.


Flex Die Grinder Performance

Flex Die Grinder
  • Max No-Load Speed: 28000 RPM
  • Collet Capacity: 1/4 in.
  • Motor Type: Brushless
  • Trigger Type: Slide switch

The Flex 24V Die Grinder houses a brushless motor with a top speed of 28,000 RPMs which is pretty impressive for a cordless model. In fact, the FX3211 outpaces many of the popular pneumatic die grinders.

Flex Die Grinder

It has four speed modes that allow you to dial in the RPMs from 10,000 all the way up to 28,000. Flex utilizes a slide switch with a lock-on feature, rather than a paddle trigger, which is more advantageous for extended use.

Speed SettingSpeed (RPM)
Level 110,000 RPM
Level 216,000 RPM
Level 322,000 RPM
Level 428,000 RPM

Carving wood, shaping stone, and de-burring metal are all well within the scope of work with this range of speeds. There’s also anti-kickback technology that lets you work with confidence.

Flex Die Grinder

Swapping bits is pretty simple. Press down on the spindle lock and rotate the bit until you feel it click into place. Then, using the included wrench, loosen the collet by turning it counterclockwise and inserting the new bit.

Flex Die Grinder Design Notes

Flex Die Grinder
  • Model: Flex FX3211
  • Power Source: Flex 24V battery
  • Weight: 3.5 lbs. (bare), 5.1 lbs. (with 3.5Ah battery)
  • Length: 16 in.

Compared to some of the pneumatic models, the Flex FX3211 is significantly larger. It measures 16 inches from tip to tail and weighs 5.1 pounds with a 3.5Ah Stacked Lithium battery. The front and rear grips are draped in textured rubber overmold for improved handling. Its long, barrel-grip design lends itself well to two-handed operation for precision applications.

Overall, this die grinder is balanced really well, especially with a 3.5Ah battery. To me, that seems like the ideal size, but if you need a little more runtime you can always go bigger.

Additional Features

  • Removable dust filters
  • Compatible with all Flex 24V batteries

Flex Die Grinder Price

This 24V die grinder retails for $219 as a bare tool. Flex backs it with a standard 5-year limited warranty but if you register your purchase within 30 days you’ll be eligible for the Flex Founder’s Limited Lifetime Warranty.

The Bottom Line

After considering the performance and design of the Flex 24V Die Grinder, it’s clear to us that the FX3211 is a force to be reckoned with. It offers an excellent range of speeds and the slim, ergonomic design is both comfortable in the hand and easy to maneuver. Overall, this is a very effective tool for shaping materials and accessing tight spaces. While there is still some debate among tradesmen concerning slide switches versus paddle switches, we believe it simply comes down to personal preference. Who knows? Maybe we’ll see more trigger options as the Flex 24V lineup develops.

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