A reciprocating saw earns its keep during demolition, rough framing, and plumbing work because one tool cuts wood, metal, drywall, and plastic with a simple blade change. Cordless models add the freedom to work on a ladder, in a crawl space, or out on a deck without dragging a cord. The saw is especially handy for removing drywall with a reciprocating saw, where a controlled plunge cut opens a wall quickly without damaging the studs behind it.
Why 20V MAX is a rating, not a battery voltage
The number on the tool nameplate is a marketing rating, not the voltage you will read across the battery terminals. A 20V MAX pack holds five lithium-ion cells wired in series, and each cell runs at a nominal 3.6 volts, which adds up to 18 volts under load. The 20 volt figure is the peak voltage of a freshly charged pack. The same chemistry appears across the industry, and the story behind cordless power tool voltage ratings explains why one brand calls the same battery 18V and another calls it 20V MAX.
| Label | Cells in series | Nominal voltage | Peak voltage | Typical tools |
|---|---|---|---|---|
| 12V MAX | 3 | 10.8 V | 12 V | Compact drivers, small saws |
| 18V | 5 | 18 V | 20 V | Full-size drills and saws |
| 20V MAX | 5 | 18 V | 20 V | Full-size drills and saws |
| 36V to 40V MAX | 10 | 36 V | 40 V | Mowers, heavier outdoor gear |
| 54V to 60V MAX | 15 | 54 V | 60 V | High-output grinders, big saws |
What drives runtime is the ampere-hour rating and the cell quality, not the sticker. A 5.0 Ah pack stores about 90 watt-hours at 18 volts, while a 2.0 Ah pack stores about 36. A reciprocating saw draws 500 to 900 watts under load, so the difference shows up as roughly 20 minutes of continuous cutting versus 8.
Voltage ratings also drive charger and pack design. Most brands keep a single pack shape across the lineup, but the charger class matters: a fast charger tops a 5.0 Ah pack in about an hour, while a standard charger takes two to three. Contractors who run multiple crews standardize on one platform so batteries and chargers can be swapped between sites.
Specs that matter: stroke length, SPM, and orbital action
Three numbers define how a reciprocating saw cuts. Stroke length is the distance the blade travels per stroke, typically 1-1/8 to 1-1/4 inches on modern saws, and longer strokes remove more material per pass. Strokes per minute range from 0 to 3,000 on variable-speed models, and the trigger lets you feather the speed for metal or plastic. Orbital action swings the blade in an ellipse, which speeds up aggressive cuts in wood but should be off for metal and flush cuts. Independent reviews of the 20V MAX XR reciprocating saw show that brushless motors hold stroke speed under load far better than brushed designs, which keeps cuts moving through nail-embedded lumber.
Blade speed under load is the number reviewers test, because an unloaded saw spins fast and a loaded saw stalls. A brushless saw holding 2,700 strokes per minute in a 2×4 cut finishes the pass in half the time of a brushed saw that sags to 1,800. That difference shows up as battery savings too, since a stalled motor wastes energy as heat.
Reading a spec sheet
Look for three details beyond the headline numbers. Tool-free blade change saves minutes on every swap. A pivoting shoe lets you set cutting depth and brace the saw against the work. Vibration control, usually a counterweight or a rubber grip, matters on long cuts because fatigue shows up in the cut line. Weight with battery, typically 7 to 10 pounds for full-size models, decides how long you can hold the saw overhead.
Safety, recalls, and keeping the saw in service
Any power tool can develop a defect, and the industry has seen its share of recalls. The safety risks, affected models, and repair options in power tool recalls follow a pattern worth knowing: a component fails, the manufacturer issues a notice with model numbers and serial ranges, and owners either send the tool in for repair or receive a replacement. Checking the recall database before buying used tools is a two-minute habit that prevents a serious injury.
Pre-start inspection checklist
- Confirm the blade is rated for the material and speed, and that it is installed in the correct direction.
- Check the blade clamp; a loose clamp lets the blade walk or eject at speed.
- Verify the shoe is secure and adjusted for the cut depth.
- Inspect the battery contacts and housing, or the power cord on corded models.
- Test the trigger and the blade guard before the first cut of the day.
Between jobs, clean the blade clamp with compressed air, wipe the blade, and store the saw with the blade removed or retracted. A saw that lives in a dusty gang box needs its vents blown out weekly, because lithium-ion packs throttle output when the motor overheats.
Records matter for fleet tools. Keeping the model number, serial number, and purchase date for each saw makes recall checks quick, and a simple logbook or spreadsheet beats trying to remember which saw came from which job. The same record keeps warranty claims moving when a tool fails early.
Cutting into walls without disaster
The most common reciprocating saw accident is cutting into something hidden. Before the first plunge, confirm what is inside the wall: electrical cable, plumbing, and gas lines all hide behind drywall, and a saw blade does not stop at the first one. The steps for cutting into a wall with a reciprocating saw start with a stud finder and a voltage detector, then a shallow pilot hole with a drill to confirm the cavity is clear.
- Scan the wall with a stud finder and a non-contact voltage tester, and trace the path of any outlet or switch.
- Drill a pilot hole with a quarter inch bit and probe the cavity with a wire or an inspection camera.
- Set the saw shoe against the wall and start the cut at low speed with the blade tip in the pilot hole.
- Let the blade settle to full depth before increasing speed, keeping the shoe flat against the surface.
- Cut along the marked line with light pressure, and stop the saw before pulling it out of the kerf.
For door and window openings, cut the drywall on the waste side of the line so the finished edge stays clean, then finish corners with a utility knife. Keep the blade tip clear of the far side of the cavity until the cut is planned, because a plunge through both faces doubles the damage.
Metal cutting needs a different approach than wood. Switch to a bimetal blade with 10 to 14 teeth per inch, cut at low speed, and let the weight of the saw do the work. Cutting nails with a wood blade dulls the teeth fast and can throw the cut out of line.
One battery platform across the lineup
The battery is the most expensive part of any cordless system, which is why platform compatibility matters more than the saw itself. A 20V MAX pack that runs the reciprocating saw also powers drills, impact drivers, grinders, and outdoor equipment such as the cordless 20V MAX mower. One charger and a set of packs covers the whole trailer, and buying bare tools instead of kits pays off once the packs are already on hand.
Capacity planning follows the job. Two 5.0 Ah packs rotate through the charger for a full day of demolition, while a 2.0 Ah pack keeps the saw light for overhead work. High-output packs with extra cells deliver more current for the same voltage, which matters for a saw that needs bursts of power in nail-laden wood. Battery condition also shows up early in saws, because a sagging pack slows the blade before it kills the tool outright.
Selecting a saw for construction work
Buy for the material mix, not the brand. Reciprocating saw selection and usage for construction work comes down to three classes: compact saws with short strokes for one-hand cutting and tight spaces, full-size saws with 1-1/4 inch strokes for general demolition, and heavy-duty models with higher power and metal housings for continuous use. Blade selection matters equally: a 6 TPI blade for fast wood cuts, 10 to 14 TPI for metal, and bi-metal blades that survive nail strikes.
Rental fleets and tool libraries stock full-size saws for good reason: the middle class covers framing, plumbing, and demo work without the cost of a specialty model. Add a compact saw later if overhead cuts or crawl spaces become a regular part of the job.
Match the blade to the material, keep the shoe planted, and change blades when the cut slows. A sharp blade and a charged battery will outwork a bigger saw that is dull and drained, and the saw that fits your hand gets picked up more often than the one with the longest stroke on paper.