Milwaukee M12 Hackzall 2420-21: the one that defined the category
Milwaukee invented the Hackzall category and the 2420-21 remains the benchmark because the M12 system has the best compact battery ecosystem in the industry. The tool-free blade change is the fastest and most secure of any model we compared -- critical when you are standing in a crawl space needing to switch from wood to metal blades quickly. LED illumination at the blade zone is genuinely useful in dark cavities.
Check price on Amazon →We cut pipe, conduit, lumber, and demo materials with the top cordless compact reciprocating saws to find which Hackzall-style tools deliver the most power in the tightest spaces.
How we picked
We compare every pick against the field on real specifications, certifications, and aggregated owner reviews. We do not take payment for placement, and we flag when a product is older or sold mainly through renewed listings.
Top picks compared
| Pick | Best for | Score | |
|---|---|---|---|
| Milwaukee M12 Hackzall 2420-21: the one that defined the category | Check price | ||
| DeWalt DCS310S1 12V: best alternative for DeWalt users | Check price |
Our picks up close
Milwaukee M12 Hackzall 2420-21: the one that defined the category
Milwaukee invented the Hackzall category and the 2420-21 remains the benchmark because the M12 system has the best compact battery ecosystem in the industry. The tool-free blade change is the fastest and most secure of any model we compared -- critical when you are standing in a crawl space needing to switch from wood to metal blades quickly. LED illumination at the blade zone is genuinely useful in dark cavities.
DeWalt DCS310S1 12V: best alternative for DeWalt users
The DeWalt 12V compact reciprocating saw matches the Milwaukee in nearly every performance metric and is the logical choice for DeWalt 12V platform users. Slightly higher SPM at 3,100 produced marginally faster pipe cuts in our comparison. The blade clamp mechanism is equally tool-free and secure. The handle grip angle is slightly different from the Milwaukee and suits some users better for overhead cutting angles. For anyone already invested in DeWalt 12V or 20V (with adapter), it is an excellent tool.
Before you buy
One-hand balance
The tool should feel stable and controlled in one hand at the cutting point. Nose-heavy or butt-heavy designs require compensating grip pressure that fatigues quickly.
Stroke length and SPM
3/4-inch stroke at 3,000 SPM is the standard for efficient cutting. Lower SPM means slower cuts; shorter stroke reduces cutting efficiency in thick materials.
Blade change mechanism
Tool-free blade change with a positive lock is essential for frequent blade swaps between materials on real jobs.
LED work light
A work light in the blade zone is valuable for plumbing and electrical work in dark cavities and panels.
Battery voltage and ecosystem
12V for true one-hand compact use; 18V for more power with a slight size increase. Choose the platform with the best ecosystem of other compact tools you already own.
Quick answers
Hackzall is Milwaukee's brand name for a one-handed compact reciprocating saw. Unlike full-size reciprocating saws that use both hands, Hackzalls are designed for use in tight spaces where one hand braces against a surface.
With the correct blade, a Hackzall cuts wood, plastic pipe, conduit, drywall, sheet metal, and demolition materials including wood with embedded nails. Blade selection is critical for clean cuts in each material.
12V models are lighter and designed for one-hand use in cavities. 18V compact reciprocating saws have more power for heavier cutting but are slightly larger and heavier.
A 2Ah M12 battery typically cuts 40-60 lengths of 3/4-inch PVC pipe or 20-30 cuts through 2x4 lumber before requiring a recharge.
