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Astro Pneumatic Tool

Astro Tools 401K 0.401" "Thor Super Duty Long Barrel Air Hammer/Riveter

  • Based on 208 reviews
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Availability: In Stock.
Fulfilled by Amazon
Arrives Wednesday, Oct 21
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Features

  • Maximum power .401" shank air hammer for heavy duty automotive and industrial applications
  • Specifically developed THOR model with stroke length and ported valvebody for power that matches or beats the top premium options from tool trucks
  • Newly designed tilt valve trigger for sensitive power adjustment at your finger tips
  • Features internal brake vibration damping system for less fatigue
  • No nonsense design: A rotatable forward grip, sensitive trigger and industry leading power
  • Includes quick change chuck, 10.25" length, Hi-Flo fittings suggested
  • Bare tool, bits sold separately

Description

The Astro Tools 401K 0.401" Shank "THOR" Long Barrel Air Hammer/Riveter is a maximum power air shank hammer for heavy duty automotive and industrial applications. This tool is a specifically developed THOR model with stroke length and ported valve body for power that matches or beats the top premium options in tool trucks. Easily adjust the power with the newly designed tilt valve trigger in this air hammer. In addition, this tool features an internal brake vibration damping system for less fatigue with a no-nonsense design that includes a rotatable forward grip, sensitive trigger, and industry leading power. Specifications: Air Inlet: 1/4" NPT, Chisel Shank Size: 0.401”, Piston Stroke: 3-5/8", Stroke Speed: 2,100 BPM, Net Weight: 5.31 LB, Length: 10.25", Hose Size: 3/8", Air Pressure: 90 PSI

Brand: Astro Pneumatic Tool


Power Source: Air_powered


Maximum Chuck Size: 0.4 inches


Color: Grey


Included Components: 0.401" Shank "THOR" Long Barrel Air Hammer/Riveter


Power Source: Air_powered


Maximum Chuck Size: 0.4 inches


Additional Features: Durable


Maximum Torque: 120 ft-lb


Maximum Power: 0.4 hp


Torque: 120 ft-lb


Drill Type: Hammer Drill


Drilling Capacity Wood: 0.4 inches


Compatible Devices: Air compressors


Drilling Capacity Metal: 0.4 inches


Color: Grey


Material Type: Chrome Vanadium Steel


Item Dimensions L x W x H: 0.39"L x 0.39"W x 0.39"H


Item Weight: 6.2 pounds


Brand Name: Astro Pneumatic Tool


Included Components: 0.401" Shank "THOR" Long Barrel Air Hammer/Riveter


Model Number: 401K


UPC: 745227080557


Number of Packs: 1


Global Trade Identification Number: 57


Unit Count: 1 Count


Manufacturer: Astro Tools


Manufacturer Warranty Description: Manufacturer’s Warranty


Number of Items: 1


Item Type Name: Astro Tools 401K 0.401" "THOR" Long Barrel Air Hammer/Riveter


Manufacturer Part Number: 401K


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Wednesday, Oct 21

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

    • This is the one.
Style: Industrial
It's powerful. I have a few air hammers, including the bigger brother to this, the 498k, which is more powerful, but bigger, harder to use, and tool choices are more limited. The bushing sold to downsize it is a little clumsy ...the 401k is a better choice. A friend has a Snap-on, the power seems identical. And it's a great deal. "Good deal" and "snap on" don't belong in the same sentence.. This has been trouble free, as have many other Astro pneumatic tools.. The trigger is real good, but a little too much squeeze results in a lot of power..if I want to be delicate (funny term for air hammer work), I use an aircraft 2x rivet gun. Just a not so powerful, very controllable 401 shank air hammer. Any powerful air hammer might be limited by the hose and fittings. I just live with it. I blip the trigger...if you hold it down, the power drops a bit, the first few hits are harder than those that follow. Anything recommending some giant compressor for impact tools is weird, they just are usually not used continuously, so it isn't a factor like it is for running a sandblaster, needle scaling a bunch of rust, grinding, even painting. If you're doing suspension work, any small compressor that can fill it's tank to 120 or so psi will run this just fine. You just may have to pause while it refills. ... show more
Reviewed in the United States on November 2, 2025 by john w.
    • Powerful tool, for the money
Style: Industrial
Decent bang for the buck. Chisel and other tools sold separately, of course. Hits fairly hard, but doesn't seem to hit as hard as the Snap On version.
Reviewed in the United States on June 28, 2026 by KingPawn
    • Best you can get for the money
Style: Industrial
Other technicians borrow mine all the time. There's isn't a better impact hammer for the money. I mean just look at the thing. It's a beast lol. If you don't run water thru it and don't over lubricate it will last a long time.
Reviewed in the United States on April 3, 2026 by MN Dude
    • Great!
Style: Industrial
I use this tool professionally. It gets used a few times a week. I have no complaints really hard hitting on par with snapon.
Reviewed in the United States on July 21, 2026 by tyler
    • Very powerful
Style: Industrial
Review Image by Ham
This air hammer has POWER. I run it at 90psi with a 15gal compressor that puts out 4.3 SCFM @ 90psi. So far I've used the Astro Thor 401k air hammer to push out CV axles from the hub, free up rusted-on brake rotors, and pushed out 10"+ long heavy bolts that were seized in bushings. It's a life saver, and an outstanding value for the price. Check out the Torque Test Channel on YouTube. They showed that this air hammer punches way above it's price point. ... show more
Reviewed in the United States on April 3, 2026 by Ham
    • Disappointed
Style: Industrial
Powerful hammer. I am a tech at a dealership and have used it for a few months working on suspensions. Hammer shook itself apart twice and now is not usable. Probably would be ok for occasional use but if you are going to use it regularly I would go with a Snap on or other name brand hammer.
Reviewed in the United States on April 11, 2026 by JeepBob
    • Highest Value Air Hammer
Style: Industrial
This air hammer is worth it's weight in gold. I purchased it because of the Torque Test Channel on YouTube and it has proved itself multiple times in just a few days of use. I stayed away from air hammers because of their price and I've been getting along fine using my 4 pound sledge and pickle fork set. After watching several videos and other technicians recommending getting an air hammer I purchased the 401K Thor. The 498 Thor was tempting, but for regular automotive work you truly cannot beat the price of this tool. It is a big air hammer but is definitely extremely well made, functions perfectly, and saves an incredible amount of time and effort. ... show more
Reviewed in the United States on April 18, 2025 by Luke
    • There’s a reason nobody can really pick up THORS hammer, but Astro did!
Style: Industrial
Astro is just the best sneaky brand in special tools and air tools. I had a heavy influence from YouTube when picking an air hammer to go with, so I decided to take the leap on the THOR, and I’m very glad I did. There’s not much this air hammer couldn’t get off for me. Plenty powerful enough for me to force out ball joints, and delicate enough to spin a stripped hex bolt free! Point and shoot, simple as that. The size is perfect, especially with the long barrel design to give yourself extra leverage and grip when in use. The ONLY thing I’d say I wish was better, was a more broader trigger. I feel like this air hammer is 0-100 very quick and it took some getting used to. But don’t be fooled, it’s very hard to dethrone this air hammer in my opinion. ... show more
Reviewed in the United States on November 18, 2025 by Jacob L.

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