Note: This post contains affiliate links. If you use these links to buy something, we may earn a commission.
If you are a plumber or electrician, you spend half your life inside a vanity cabinet or halfway up a drop ceiling. In those spaces, a full-sized “Sawzall” is useless. It requires two hands and shakes the entire wall.
Enter the Milwaukee M12 FUEL Hackzall (2520-20).
It looks like a toy, but it is arguably the most important tool in the Red lineup. It created an entire category of “One-Handed Reciprocating Saws.”
Here is why it never leaves the pro’s tool bag.
The “One Thing” (The Hook)
True One-Handed Balance. Most reciprocating saws are nose-heavy. If you try to use them with one hand, the blade wanders and chatters. The M12 Hackzall is balanced perfectly over the grip.
- The Result: You can hold a PVC pipe with your left hand and cut it with your right hand. For cutting copper or PEX under a sink, this stability is critical. It acts more like a scalpel than a demolition saw.
The Good
- Stroke Length (5/8″): This sounds short (standard saws are 1-1/8″), but it is intentional. The shorter stroke reduces vibration and makes it easier to start cuts on round pipes without the blade jumping all over the place.
- The Size: At just 11 inches long and 4.1 lbs (with battery), it fits into joist bays and cabinets where a standard 18V tool simply cannot physically fit.
- Vibration Control: The FUEL (Brushless) model features a “dual gear counterbalance” mechanism. This drastically reduces the wrist-shaking vibration found in the cheaper, brushed version.
The Bad (The #1 Complaint)
The Battery “Wiggle.” This is a known flaw of the M12 battery design, not just this tool. The plastic tabs on the batteries—especially the wider “XC” batteries—can fatigue over time.
- The Issue: After years of vibration, the battery can loosen or even unclip slightly during heavy use. It doesn’t happen often, but when it does, the tool cuts out mid-cut.
Note: Do not confuse this with the cheaper “Brushed” version (2420-20). That model is significantly weaker and vibrates your hand aggressively. Spend the extra money for the FUEL.
The Verdict
Who is this for?
- Buy it if: You are a Plumber, Electrician, or HVAC Tech. It cuts 2-inch PVC, EMT conduit, and copper pipe faster and cleaner than a hacksaw. It is an essential trade tool.
- Skip it if: You are doing Demolition. If you need to cut through a 4×4 post or remove a window frame, this tool is too slow. It lacks the stroke length to clear sawdust from deep cuts effectively. Buy the M18 Sawzall for demo.
Specs at a Glance
| Feature | M12 FUEL Hackzall (2520-20) |
| Stroke Length | 5/8 Inch |
| SPM (Speed) | 0-3,000 |
| Length | 11.0 Inches |
| Weight | 4.1 lbs (w/ Battery) |
| Motor | Brushless (FUEL) |
| Warranty | 5 Years |
Export to Sheets
[ Check Price at Home Depot ] (Affiliate Link) [ Check Price on Amazon ] (Affiliate Link)