Best tap and die sets for plumbers

The GEARWRENCH 82812 is the one I'd keep on the truck if I could carry one set. It has 48 taps and dies from 4-40 to 3/4 inch and 3 to 18 millimeters. GEARWRENCH's own FAQ adds pipe taps and dies in 1/8 and 1/4 inch. That pipe pair is why it's my top pick for plumbing.

One note on those pipe sizes. GEARWRENCH lists them as "Pipe 1/8" & 1/4"" but doesn't say NPT or another thread form. If you need a named 1/8 inch NPT tap and die, IRWIN's 1813817 lists it outright. I'd check the marking on the tap before you cut a fitting you can't replace.

The handles are the other reason. GEARWRENCH's T-wrenches have a 72-tooth ratchet with a 5° swing arc and a reversing lever, so you don't turn hand over hand. Under a sink or behind a water heater, you often can't swing a full turn. A short back-and-forth stroke still cuts.

The Twist Lock guide cuts down on the die guide's "walk back" and keeps the die centered while you cut. A die that starts crooked cuts a crooked thread, and a nut won't run on it cleanly. The guide helps most when you're working one-handed on a rod overhead.

Reach is better than a plain die stock. The die adapters take round and hex dies and fit GEARWRENCH's 3/8 inch drive Pass-Thru ratchets and socket accessories. The extension adapters work with any 3/8 inch drive extension, so you can thread a stud deep in a cabinet.

In the case you get 2 ratcheting T-handles, 3 sizes of tap adapter, 2 die adapters, 2 extension adapters, a sliding T, a 4 mm hex key, 5 screw extractors and SAE and metric thread gauges. GEARWRENCH says the set meets or exceeds ANSI, ASME, DIN and Federal specs.

Two things to know before you buy. It's big: GEARWRENCH lists 18.25 pounds and 21.5 by 13.5 by 3.5 inches. And the lifetime warranty covers the wrenches and adapters only. GEARWRENCH gives no warranty on the taps and dies, so treat them as wear parts.

Drill America's DWTPT set is a different kind of pick. It's six NPT pipe taps, 1/8, 1/4, 3/8, 1/2, 3/4 and 1 inch, in a wooden case. There are no dies and no handle. It's the only set here that reaches 1 inch pipe thread, which is why I'd add it to the GEARWRENCH.

Drill America says these carbon steel taps are made to clean up or re-thread damaged or jammed pipe threads. They work on ferrous and non-ferrous metal. Think of a tee with a chewed inside thread, a fitting packed with old dope, or a brass valve port that won't start straight.

Read the size the right way. The nominal size of a pipe tap is the size of the fitting it threads, not the size of the tap. A 1/2 inch NPT tap is much bigger than half an inch across. MSC's drill chart calls for a 23/32 inch hole before you tap 1/2-14 NPT.

The taps are tapered, like the thread they cut: 3/4 inch per foot, per Drill America. Each one has a 2-1/2 to 3-1/2 thread chamfer, so it starts with a few partial threads. Because the thread tapers, how far you run the tap decides how tight the fitting goes in. Run it a little, try the fitting, then go further.

Plan on effort with the big sizes. MSC notes that pipe threads need 100% thread depth and more cutting force than regular machine threads. The 1 inch tap cuts 11-1/2 threads per inch, and you'll want a big tap wrench that fits its square shank. The set doesn't include one.

Seal what you thread. MSC says NPT threads need sealant; only the Dryseal NPTF form seals metal to metal. See our guides to pipe dope and PTFE tape.

IRWIN's 1813817 is the set for mixed inch and metric work, and the one that names its pipe thread. IRWIN's listing includes a 1/8"-27 NPT tap and die and a 1/8"-28 BSP tap and die. IRWIN calls it part of its Performance Threading System.

Having both pipe threads helps. NPT is the American taper pipe thread. BSP is the British pipe thread, and at 1/8 inch it runs 28 threads per inch instead of 27.

One thread per inch is easy to miss by eye, so if an NPT fitting won't start, check the count with a pitch gauge before you force it. IRWIN puts both in one case, so you can cut whichever thread the part needs.

The bolt range is wide. There are six machine screw sizes from 4-40 to 12-24. There are ten fractional sizes from 1/4-20 to 1/2-20, each in coarse (NC) and fine (NF). And there are sixteen metric sizes from 3 mm-0.5 to 12 mm-1.75.

The metric list is the reason to pick it over the GEARWRENCH 3885. It has fine pitches like 10 mm-1.25 and 12 mm-1.25 next to the coarse ones. That covers metric hardware on equipment that isn't built to inch sizes, without a second case.

It also has five spiral-flute screw extractors, EX-1 through EX-5, for a snapped bolt or a broken screw in a fixture mount. For bigger breaks, see our screw extractor guide.

Where it falls short of the GEARWRENCH 82812: fractional sizes stop at 1/2 inch, not 3/4. IRWIN's listing doesn't describe the handles or a warranty, so I mark the warranty as not listed. On the day of the update, Amazon showed 11 in stock with more on the way, and Amazon itself is the seller.

A thread chaser fixes a thread; it doesn't cut a new one. VEVOR says its XRSS049 traces and repairs worn or damaged threads and cleans out dirt and corrosion without changing the thread. That's what you want for a rusty strap bolt or a tank bolt the nut won't pass.

A cutting die can follow the old thread, but it can also start a new one if it goes on crooked. A chaser is made to restore. That's why I'd keep one next to a cutting set instead of using one tool for both jobs.

The set has 22 taps, 24 dies and 3 thread files, color coded. UNC sizes are silver, from 1/4-20 to 5/8-11. UNF sizes are black, from 1/4-28 to 5/8-18. Metric sizes are gold, ten of them from M6x1.0 to M14x1.5. The color makes it quick to grab the right one out of the case.

The thread files are easy to overlook. A file works on an outside thread when you can't get a die over the end, like a bolt with a mushroomed tip. SAE file 1 covers 9, 10, 12, 16, 20, 27, 28 and 32 threads per inch. File 2 covers 11 to 24. The metric file covers 0.75 to 3.00 mm.

VEVOR lists the steel at HRC 55 to 62 and includes a carry case. The files have removable plastic covers over the cutting edges. VEVOR's listing doesn't mention a handle, so check you have a wrench or tap handle that fits before the job.

There are no pipe sizes here, and nothing below 1/4 inch or M6. Pair it with the GEARWRENCH 82812: one cuts threads, the other saves them. Amazon is the seller.

The GEARWRENCH 3885 puts the 82812's handle system in a case a quarter of the weight. It's 4.55 pounds, in a case 12 by 7 by 3 inches. You get 34 SAE taps and dies and no metric. If your hardware is inch sizes, it does the daily jobs in less space, and it fits a truck drawer where an 18-pound case won't.

The ratchet is the same. GEARWRENCH says its T-wrenches use a 72-tooth mechanism for a 5° swing arc, with a reversing lever. Its FAQ puts the benefit simply: quick turns with little hand movement, which means less hand fatigue on a long thread.

GEARWRENCH lists one medium ratcheting T-wrench, a small and a medium tap adapter, a medium hex die adapter, a sliding T, a thread gauge, a 4 mm hex key and a spacer adapter. The die adapter takes round or hex dies. The tap adapters lock on their own and release safely.

There's a spring-loaded cap for a quick release of the large tap adapter. The Twist Lock guide keeps the die centered, the same as the bigger set. And the drive extension adapters work with 3/8 inch drive extensions when the thread is out of reach.

GEARWRENCH says this set can thread carbon steel, aluminum and mild steel. That covers most of the hardware a plumber touches: steel bolts, rod and brackets. Stainless isn't on that list.

What's missing: GEARWRENCH's page doesn't list the exact SAE sizes or any pipe sizes, so I mark pipe thread as not listed. As with the 82812, the wrench and adapters have a full lifetime warranty and the taps and dies have none. For metric, GEARWRENCH sells a matching 42-piece metric set, the 3886.