The Garage Tools

20V Hercules 3/8 in. Compact Impact Wrench Review: Compact and Powerful

This little compact 3/8th impact packs a mighty punch.
Harbor Freight 20V Brushless Cordless 3/8 in. Compact 3-Speed Impact Wrench
Peter Nelson

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Small and mighty isn’t a foreign concept when it comes to modern, lithium-powered impact wrenches. But that doesn’t mean it ever gets old. Recently, I put a 12V cordless ratchet by Hercules to the test, Harbor Freight’s house brand for its toughest and torquiest products. 

This handy tool fared quite well, and similar to my experiences with its 20V ½ inch impact cousin that I’ve put through the wringer in the past two or so years, it’s an overall quality piece. But what about something in between? This might seem overkill or unnecessary, but it actually fits perfectly in any home wrencher’s loadout: Hercules’ 20V Brushless Cordless ⅜ inch Compact Impact Gun.

Harbor Freight recently dispatched one of these to my shadetree HQ for testing. And while the results weren’t surprising, the convenience behind its tiny size was much appreciated. I’m also all about the 3/8th life now.

Harbor Freight 20V Brushless Cordless 3/8 in. Compact 3-Speed Impact Wrench

Good Overall Construction

The thing about this ⅜ inch drive unit is it’s essentially just a scaled down version of the impact that I already have: same good materials quality, same grippy surfaces. It’ll pick up scratches and grease stains, but big deal, all impacts do. And it’s a mark of pride when they start looking a tad haggard on the outside but still perform their duties without issue. 

It fits in the hand quite well, too—the handle is sized just right for my grip.

Even though it’s smaller, it’s still got a solid/hearty feel to it, just with less overall weight as the gun itself comes in at 2.6 lbs. Familiarity runs deep, too, as it’s in the same battery environment. This means that swapping 20V batteries with the ½ inch unit is a cinch, and they charge on the same dual quick charger that also accommodates the 12V cordless ratchet.

If you’ve already established some degree of investment in another brand’s offerings, like DeWalt or Milwaukee, then you might not be inclined to push that aside for a new brand. But if you’re starting fresh it’s a big, new, exciting place to be.

I’ve accumulated a few 2.5, and 5.0 amp-hour batteries over the past couple of months, and it’s great that I can throw them on either impact gun with ease.

Excellent Size, Good Specs

At first glance, the ⅜ inch unit doesn’t look tremendously smaller than its ½ inch sibling, especially sitting next to each other in a digital photograph. But rest assured, it’s noticeably smaller and lighter, especially when adorned with a smaller 2.5 amp-hour battery.

It’s just enough smaller that it fits in even tighter places, such as behind a car’s hub for doing a full rear brake job, which is what I primarily recently used this gun for. Then, grabbing ahold of it to quickly undo other tightened-down fasteners—which the cordless ratchet might not break loose—is easy, too. 

Harbor Freight boasts that this three-speed unit will put out as much as 525 ft. lbs of breakaway torque and 229 ft. lbs of fastening torque. The hardware of my lithium-powered affection didn’t need this much, but I’ll report back in a future blog when I’m able to put these figures to the test.

Since ⅜-inch extensions and sockets are smaller, even the rough-and-tumble impact units that I use by default can clear the tightest crevices than the dimensionally bigger ½ inch stuff I used to use a lot more. My recently purchased ⅜ inch impact socket set is small and light, as well as incredibly useful for most non-Torx hardware (I ought to buy a similar kit for Torx and hex) on my BMW 128i and Audi S4.

Plus, this overall smaller and lighter package makes for easier to lug around, as I found out during a recent visit to my local junkyard. Less weight and room in my massive tool bag means more room for charge pipes, trim pieces, and other spare bits that I’ve been hoarding as of late.

Harbor Freight 20V Brushless Cordless 3/8 in. Compact 3-Speed Impact Wrench

The Competition

Just like Harbor Freight’s comparable ½-inch Hercules unit, there are plenty of options to choose from by other brands.

Dewalt’s 20V MAX XR impact wrench sports similar weight, specs, and dimensions, though even on sale commands around $100 more before batteries and charger at $165. Normally it’s around $200 when not on sale That’s right, the Harbor Freight option sits at just $65. Milwaukee’s option, the M18 Fuel 3/8th Compact is a great middle-ground at $140 on sale, is 2V shy of the former two, yet has a little more torque output. 

It also seems like, generally, HF’s batteries are on the less expensive end, though we can’t quote any differences in performance or longevity here. At least not yet. 

Our Verdict

Harbor Freight’s 20V Hercules ⅜-inch compact impact wrench completes a solid loadout alongside a similar ½ in. impact and ⅜ in. cordless ratchet. It’s properly small, puts out great torque for quick and easy action, and can be quite light when paired with one of HF’s smaller battery options. It also seems like it can get thrown around, which is a good sign that it’ll hold up in anyone’s toolbox for years to come.