Cutting cast iron with a reciprocating saw is a real test of patience. The wrong blade chews through itself in minutes, while the right one chews through a soil pipe, an old radiator, or a cracked stove part as if it were soft pine. The blade you grab needs the tooth geometry, body thickness, and cobalt-rich blend that survives dense, brittle, abrasive material without snapping or glazing over.
This roundup sorts through eight blade sets that claim to handle cast iron and rates them by what actually matters: TPI (teeth per inch, which controls cut smoothness and speed), blade thickness, bi-metal construction (two metals welded together for flexibility and edge hardness), cobalt content, and length. Most blade packs here carry 8% cobalt for heat resistance. The trade-off shows up when you cut anything thinner, where coarse teeth grab and shatter the workpiece. Match the blade to the job, and the saw becomes a real dismantling tool instead of a frustrating one.
The Essentials At A Glance
Milwaukee Sawzall Reciprocating Saw Blade Set 12 Pc
DEWALT Reciprocating Saw Blade Set for Metal Wood Iron 12 Piece Bi-Metal (DW4892)
15 Pack 9 Inch 20/24 TPI Reciprocating Saw Blades for Metal Cutting
25 Pack 9 Inch 20/24TPI Reciprocating Saw Blades for Metal Cutting, Bi-Metal Sawzall Blades with 8% Cobalt
15 Pack 9 Inch 8/10 TPI Reciprocating Saw Blades for Diablo Sawzall Blades
DEWALT Reciprocating Saw Blades 10 Piece Bi-Metal Combination Set (DW4898)
15 Pack 9 Inch 14/18 TPI Reciprocating Saw Blades for Metal Cutting
25 Pack 6 Inch 20/24TPI Reciprocating Saw Blades for Metal Cutting, Bi-Metal Sawzall Blades with 8% Cobalt
The Details Behind The Selections
The Milwaukee 12-piece set leans into the heavy end of the spectrum, with two thick body profiles: a 0.042-inch blade for general metal work and a 0.062-inch blade for extreme cutting conditions where thinner stock would whip or snap. The 1-inch blade height adds rigidity along the cut line, which matters when you push a blade through a cast iron fitting without letting it wander.
For homeowners and tradespeople who break up old boiler piping or split radiator sections, this is the kind of blade that survives a hard day on a job site. Compared to the DEWALT DW4892 that follows, the Milwaukee trades some tooth refinement for raw durability, so don’t expect clean cuts in thin sheet metal.
The Value In It
- 0.042 and 0.062-inch body thicknesses handle dense cast iron without flexing
- Tall 1-inch profile keeps cuts straight on heavy stock
- Wide blade body fits into tight spaces where thinner blades lose stiffness
- Twelve-piece count covers a range of demolition tasks
Things To Consider
- Thick body cuts slowly in thin gauge material
- Coarser tooth pattern leaves a rougher edge than finer TPI sets
Key Specs
Made For
Plumbers, HVAC techs, and homeowners breaking up cast iron boiler sections or radiator runs.
Consider Something Else When
Reaching for a fine finish in thin metal calls for the ALEXEX 15 Pack 9 Inch 20/24 TPI, which leaves cleaner edges.
The DEWALT DW4892 set is built around patented tooth geometry that pulls chips out of the cut instead of letting them pack between the teeth. The trade-off is that the tall, thick body profile drives straight cuts through heavy metal, which is exactly what you want when an old cast iron closet flange resists the saw.
For shop owners who need one blade set to cover both demolition days and renovation work, this 12-piece case keeps the right blade close at hand. You may find the thicker body slightly slow in sheet metal under 1/8 inch, where a fine-tooth blade like the ALEXEX 20/24 TPI cuts faster.
Where It Helps
- Patented tooth form clears chips efficiently for longer blade life
- Thick body profile keeps cuts straight in heavy stock
- Bi-metal construction handles heat from sustained cuts
- Storage case keeps the 12 blades organized on a job site
Worth Noting
- Thick body can feel sluggish in thin metal
- Some users may want finer TPI for finish cuts
Right Fit For
Tradespeople cutting heavy cast iron fittings, soil pipe, and thick gauge steel regularly on the job.
Look Elsewhere When
Working in tight quarters around plumbing traps calls for the shorter ALEXEX 25 Pack 6 Inch 20/24 TPI instead.
The ALEXEX 15-pack delivers a 20/24 TPI pattern, meaning 20 teeth per inch on one end and 24 on the other, with 8% cobalt blended into the bi-metal teeth. That cobalt boost raises the heat ceiling, which matters because cast iron gets a saw blade hot fast. The finer tooth count makes this set a better fit for thinner cast iron sections under 1/8 inch thick than the heavy Milwaukee set that opened the list.
Shoppers rebuilding vintage machinery or trimming a small section of cast iron pipe will appreciate the balance of cut quality and value. The trade-off shows up in thicker cast where a coarse 8/10 TPI blade chews through faster, so this is not the right pick for the densest demolition work.
Standout Benefits
- 8% cobalt blend resists heat during long cuts
- 20/24 TPI leaves a cleaner cut edge in thin cast iron
- Fifteen-pack value reduces per-blade cost
- Bi-metal construction flexes without snapping
Trade Offs
- Slower cutting pace in thick cast iron
- Storage case is not included
- Heat buildup in dense material shortens life
Feature Snapshot
Best Suited To
DIYers cutting thin cast iron pipe, drain lines, and machinery sections where a clean edge matters.
Skip It When
Tackling heavy demolition demands the more aggressive ALEXEX 15 Pack 9 Inch 8/10 TPI, which clears material faster.
This ALEXEX 25-pack takes the same 20/24 TPI formula as the 15-pack and triples the working stock. For someone spending a full weekend pulling an old cast iron radiator system out of a basement, the extra blades mean no mid-job run to the store when the teeth finally dull.
The bulk format suits a small auto shop or plumbing crew more than a one-time homeowner job. Compared to the Milwaukee set at the top of this list, the finer TPI here trades raw cutting speed for a noticeably cleaner edge on thinner sections.
Features That Help
- 25-blade count covers large dismantling projects
- 8% cobalt blend lifts the heat ceiling for longer blade runs
- 20/24 TPI handles thin cast iron cleanly
- Bi-metal teeth flex under load without fracturing
Points To Note
- Storage case sold separately
- Slower in heavy material than coarse-tooth sets
- Bulk format is overkill for one or two cuts
Who Will Love This
Auto dismantlers, plumbing contractors, and renovation crews who go through blades by the dozen.
Another Choice May Suit
Doing one small home project fits the ALEXEX 15 Pack 9 Inch 20/24 TPI, which is the same blade in a smaller pack.
The 8/10 TPI count here sits at the aggressive end of the spectrum, with eight teeth on one end and ten on the other. That coarse pattern moves through thick cast iron fast, which is what you want when a saw is bogged down and the blade is just polishing the cut instead of biting. The 8% cobalt blend and bi-metal build keep the teeth from wearing flat in the heat of a hard pull.
For someone cutting up an old boiler or breaking a cast iron bathtub into haulable pieces, the trade-off in finish quality is well worth the speed gain. Owners commonly report that running the saw at a steady, moderate pace keeps the cut on track and the blade alive longer.
What Works In Its Favor
- Coarse 8/10 TPI chews through thick cast iron quickly
- 8% cobalt teeth resist heat during heavy cuts
- Non-stick coating reduces gumming from metal dust
- Bi-metal construction flexes under stress
Small Caveats
- Leaves a rough edge in thin material
- Faster tooth wear in hard, abrasive cast
- No storage case in the package
Built With In Mind
Demo crews and serious renovators cutting thick cast iron, boiler sections, and heavy pipe runs.
Reach For A Different Pick When
Cleaner finish work on thinner stock calls for the ALEXEX 15 Pack 9 Inch 14/18 TPI, which balances cut speed and edge quality.
The DEWALT DW4898 mix runs a range of blade lengths from 6 inches to 9 inches inside one tough storage case, making it a smart pick for a workshop where cuts vary in depth. The bi-metal build across every blade gives the flexibility needed to navigate curves around fittings and the edge life needed for cast iron.
Anyone whose saw work bounces between cast iron, wood, and mixed demolition finds this set covers more ground than a single-purpose pack. The trade-off is that no single TPI in the set is as specialized as the dedicated 8/10 TPI ALEXEX set, so heavy cast jobs may run longer.
Notable Gains
- Length variety from 6 to 9 inches fits different cut depths
- Bi-metal build on every blade for longer life
- Storage case fits into standard tool kit boxes
- One set covers wood, metal, and cast iron
Honest Caveats
- No single TPI is as specialized as dedicated metal sets
- Slower in heavy cast than coarse-tooth packs
Perfect Match For
Workshop owners and serious DIYers who need one set to cover many materials and project types.
Where A Sibling Pick Shines
Pure cast iron demolition fits the ALEXEX 15 Pack 9 Inch 8/10 TPI, which is tuned for thick stock.
The 14/18 TPI pattern lands in the middle of the cut-speed-versus-finish debate: coarse enough to clear material at a fair pace, fine enough to leave a workable edge. With 8% cobalt in the teeth, this ALEXEX 15-pack handles medium-gauge cast iron where the 20/24 TPI feels too fine and the 8/10 TPI feels too rough.
Shops that cut a mix of cast iron and steel plate find this tooth count covers most tasks without swapping blades. The honest read is that extreme heavy demolition still calls for the coarser 8/10 TPI set, but most home and shop work fits right in the middle.
Where It Excels
- 14/18 TPI balances cut speed and edge quality
- 8% cobalt blend holds up under heat
- Non-stick coating reduces friction and gumming
- Bi-metal teeth flex without fracturing
Points To Keep In Mind
- Not the fastest option for very thick cast
- Pack does not include a storage case
- Edge not as clean as the 20/24 TPI set
Whose Shelf It Belongs On
Home workshops and small fabrication shops that cut medium-gauge cast iron and steel regularly.
Swap It Out When
Needing clean cuts in thin cast iron fits the ALEXEX 15 Pack 9 Inch 20/24 TPI, which finishes smoother.
The 6-inch blade length on this ALEXEX pack makes it the right pick when the cut sits between two studs, inside a vanity, or under a sink. The 20/24 TPI leaves a clean edge on thin cast iron pipe, and the 8% cobalt blend keeps the teeth from losing hardness when the cut runs long.
For plumbers snaking through tight bathroom remodels, the short reach is an asset rather than a limitation. The trade-off shows up when you need to cut through the middle of a long pipe run, where the 9-inch blades elsewhere on this list reach where this one cannot.
Practical Pluses
- 6-inch length fits in cramped work areas
- 20/24 TPI cuts thin cast iron cleanly
- 8% cobalt blend handles heat well
- 25-blade pack covers extended project runs
Less Ideal Details
- Too short for cuts deeper than 6 inches
- No storage case included
- Slows down in material thicker than 1/8 inch
Who Should Grab It
Plumbers and remodelers cutting cast iron in tight spots under sinks, between joists, and inside vanity cavities.
A Better Fit Elsewhere
Open demolition with room to swing needs the longer 9-inch ALEXEX 15 Pack 8/10 TPI, which clears thick stock faster.
What To Weigh Before Choosing Sawzall Blades For Cast Iron
Tooth Count Drives The Result
TPI is the single most important decision when picking a blade for cast iron. A coarse 8/10 TPI chews through thick pipe in seconds but leaves a ragged edge, while a fine 20/24 TPI slides through thin stock cleanly but bogs down on heavy material. The 14/18 TPI middle ground suits most mixed workloads, so a single set may not cover every project on the to-do list.
Cobalt And Bi-Metal Construction
Cast iron punishes blades with heat and vibration, so a bi-metal body (a flexible steel core with a hardened cutting edge welded on) gives the flexibility to survive the constant back-and-forth motion. An 8% cobalt blend on the teeth raises the heat ceiling and slows wear, which is why it shows up on most blades designed for metal work. The trade-off is price: cobalt blades cost more per piece than plain bi-metal.
Length And Blade Thickness
Longer 9-inch blades reach deeper cuts but whip more in dense material, so the body has to be thicker to stay stable. The Milwaukee set uses 0.042 and 0.062-inch bodies for exactly this reason. Shorter 6-inch blades stay rigid in tight spots, which is why that length works for plumbing trim work under sinks.
What Separates The Cheap Sets From The Reliable Ones
Where Shoppers Go Wrong
A common mistake is grabbing a wood-cutting blade or a general-purpose demolition blade and expecting it to survive cast iron. The teeth dull fast, the body snaps from heat, and the project grinds to a halt. Another trap is buying fine 18+ TPI blades for thick pipe; the cut slows to a polish, the blade overheats, and the teeth lose their edge in a single fitting.
Match the TPI to the material thickness first, then consider blade length, then count how many you need for the project. Skipping the matching step is what burns through blade packs without finishing the cut.
When Paying More Pays Off
The premium tier adds cobalt content, patented tooth geometry, and tighter manufacturing tolerances. A Milwaukee or DEWALT blade in this category often lasts through more cuts than a budget pack at similar per-blade pricing, because the heat resistance and tooth retention hold up over a long workday. The upgrade is worth it for anyone cutting cast iron weekly, while a one-time homeowner job may not justify the premium.
Frequently Asked Questions
Can a Sawzall blade actually cut cast iron?
Yes, with the right TPI, cobalt content, and blade thickness. A coarse 8/10 TPI blade handles thick sections, while a fine 20/24 TPI works on thin pipe. Standard wood blades will not survive the heat and density of cast iron.
What TPI works best for cutting cast iron pipe?
For pipe under 1/8 inch thick, a 20/24 TPI blade cuts cleanly. For pipe 1/4 inch or thicker, an 8/10 or 14/18 TPI blade moves through faster without bogging down. Many pros keep both on hand for the same project.
Does cobalt content really make a difference?
An 8% cobalt blend raises the heat ceiling during long cuts, which slows tooth wear. The difference shows up over a full day of cutting rather than on a single short cut, so occasional users may not notice the gain.
Why do blades break or wear out so fast in cast iron?
Cast iron is abrasive and brittle, generating heat and dust that dulls teeth fast. Running the saw too hard accelerates wear, and using the wrong TPI forces the blade to overwork. A steady, moderate pace extends blade life noticeably.
How long should a cast iron cutting blade last?
It depends on thickness, TPI, and pressure. A coarse cobalt blade through a single soil pipe may last for several cuts, while a fine-tooth blade in dense machinery may dull after one or two passes. Treat each blade as consumable and replace when cutting slows.
