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MK8 vs V6 vs Volcano vs Revo vs CHT: Which Nozzle Fits Your Printer

Compare MK8, V6, Volcano, Revo, CHT, Prusa and Creality Unicorn nozzles by thread, length and swap style, and see which ones actually interchange.

· 11 min read

Your printer takes the nozzle family its hotend was built around: a stock Ender-3 takes MK8, a Prusa MK3S takes V6, a Revo hotend takes Revo, and newer Creality and Prusa machines take their own nozzle-and-heatbreak units. Families only cross over when the maker says so or when you change the heater block or add an adapter, because two nozzles can share an M6 thread and still differ in length, sealing and construction.

If you need the basics of reading a thread callout first, start with our nozzle thread size guide. This post assumes you know what M6 × 1 means and focuses on the families themselves.

The families at a glance

Family Thread Overall length Swap style Printers it's commonly listed for
MK8 M6 × 1, 5 mm threaded 13 mm Nozzle alone, into a heater block Ender-3, Ender-3 V2, Ender-3 Pro, CR-10 series, several Sovol models
V6 / "RepRap" M6 × 1, 7.5 mm threaded 12.5 mm (Bondtech) or 13 mm (Micro Swiss) Nozzle alone, tightened hot E3D V6 and Hemera, Prusa MK3/MK3S, Prusa MINI
Volcano M6 × 1, 14.5 mm threaded 21 mm Nozzle alone, Volcano block only E3D Volcano hotends and Volcano-block conversions
E3D Revo Not published on E3D's pages Not published Nozzle and heatbreak as one unit, by hand, cold Revo Six, Revo Micro, Revo Voron and other Revo hotends
Bondtech CHT Sold in MK8, RepRap (V6) and Volcano formats Matches the format Same as the format it replaces Any hotend that takes one of those three formats
Prusa Nozzle (incl. CHT) Not published Not published Nozzle and heatbreak as one unit MK4, MK4S, MK3.9, XL, CORE One
Creality "Unicorn" Not published Not published Nozzle and titanium heatbreak as one unit, quick-swap K1C, Ender-3 V3, Ender-3 V3 Plus, newer K1/K1 Max; separate kit for K2/K2 Plus

The dimensions for MK8, RepRap and Volcano come from Bondtech's own format codes (M6×1×5×13, M6×1×7.5×12.5 and M6×1×14.5×21) and Micro Swiss's spec sheets. Where a maker doesn't publish a number, the table says so rather than filling in a forum figure.

MK8

MK8 is the nozzle that has shipped on the classic Creality Ender and CR-10 hotends for years. Micro Swiss lists its MK8 nozzle as M6 × 1.0 with a 5 mm thread and 13 mm overall length, and its compatibility list includes the Ender 2, Ender 3, Ender 3 V2, Ender 3 Pro, Ender 3 S1, Ender 3 Max, the CR-10 family, Ender 5 series, several Sovol models and more. Bondtech's MK8 CHT code (M6×1×5×13) matches those numbers.

The nozzle swaps on its own: unscrew it from the heater block, screw in the new one. E3D also makes MK8-format nozzles and says they use the same internal geometry as its V6 and Revo range.

If you own an original Ender-3, the Ender-3 hotend list shows which listings name your printer.

V6 (often sold as "RepRap" or "M6")

The E3D V6 nozzle is the most copied nozzle in hobby printing. Micro Swiss lists its RepRap/V6-style nozzle as M6 × 1.0 with a 7.5 mm thread, and Bondtech's RepRap code gives 7.5 mm threaded and 12.5 mm overall. Micro Swiss lists 13 mm overall for its own version, so expect half a millimetre of variation between makers.

E3D says its V6 nozzles fit the V6, Lite6, Chimera, Titan Aero, Hemera and the Prusa MK3 and MINI. E3D's install procedure is a hot tighten: heat a brass nozzle to 285°C (or 20°C above print temperature for plated copper, hardened steel, Nozzle X and ObXidian), wait about a minute, then tighten to roughly 2 Nm with a 7 mm spanner. Its support page warns that too much force can shear the nozzle or the heatbreak.

The Prusa MK3S is the most common printer that ships with a V6-style hotend.

Volcano

Volcano is E3D's long-melt-zone variant of the V6 platform. It uses a taller heater block and a longer nozzle so filament spends more time being heated, which raises how much plastic the hotend can melt per second. Bondtech's Volcano code is M6×1×14.5×21: same M6 × 1 thread as a V6, but 14.5 mm of thread and 21 mm overall.

Volcano nozzles are designed for the Volcano heater block. Tiny Machines 3D's E3D Volcano listing states plainly that they are not compatible with V6, SuperVolcano or Cyclops heater blocks. E3D's own Volcano nozzle product page now shows the product as discontinued and points to its help centre for legacy support, so third-party Volcano-format nozzles are where most people will be buying.

E3D Revo

Revo changes the idea of a nozzle. Each Revo nozzle is a nozzle and heatbreak preassembled as one part, so there is nothing to hot tighten. E3D says you change them by hand when cold, without tools, and puts typical changes at under 30 seconds. The heat comes from a Revo HeaterCore held on with a retention spring rather than a conventional block.

The catch: Revo nozzles are not compatible with V6-style heater blocks, and E3D says older ecosystems lose compatibility with Revo parts because the Revo cold side has a longer, wider hole for the nozzle. Within Revo, the hotends share nozzles. Revo Six has the same height, diameter and mounting as a V6, so it drops into a V6 mount; Revo Micro uses an M12 × 1.5 thread at the top; and E3D describes Revo Voron as fully compatible with the Revo ecosystem. For a Voron build, the Voron 2.4 hotend list shows what sellers name for that printer.

E3D notes you may need to re-check Z offset after a swap.

Bondtech CHT

CHT is a bore design, not a mount. Bondtech's patented Core Heating Technology adds holes inside the nozzle that split the filament into three thinner strands, so it melts from the inside as well as the outside. Bondtech sells it in three mount formats: MK8, RepRap (V6) and Volcano, in coated brass and bimetal versions.

That means "CHT vs V6" is the wrong comparison. A RepRap-format CHT nozzle is a V6-format nozzle with a different bore, and it fits wherever a V6 fits. Bondtech headlines gains of "30% or more" with a link to its white paper, limits those gains to certain materials and filament diameters, and recommends a nozzle of at least 0.6 mm to see meaningful gains.

Prusa Nozzle and Prusa Nozzle CHT

Prusa's Nextruder printers use their own nozzle. Prusa says every MK4S, MK3.9S, MK4, MK3.9, XL and CORE One ships with the Prusa Nozzle, and its CHT version is described as an all-metal high-flow nozzle "that combines both nozzle and heatbreak." Prusa calls the CHT nozzle its own design based on CHT technology and measured flow gains of 45% to 114% over standard nozzles, depending on material. The CHT nozzle is listed as compatible with the MK4, MK4S, MK3.9, XL and CORE One family, and not with the MK3S, MK3, MK2.5 or MINI.

Prusa's MK4S guide installs the nozzle cold: screw it fully into the heater block, hold the block with a wrench, and tighten to 1.5 Nm. When it's seated, the copper ring on the nozzle shouldn't be visible.

To run V6 nozzles on a Nextruder, Prusa sells a Nextruder V6 Nozzle Adapter that screws into the heater block. Prusa says it makes the Nextruder "compatible with any V6 nozzle." See the MK4S nozzle list or the CORE One page for listings that name those printers.

Creality "Unicorn" quick-swap nozzles

Creality's K1C launch post describes a tri-metal "Unicorn" nozzle: a copper body with a hardened steel tip, integrated with a titanium alloy heatbreak, swappable with one hand, rated to 300°C on that printer. The nozzle and heatbreak come out as one piece.

Two things trip people up:

  • There are two Unicorn kits. Creality sells one for the K1C, Ender-3 V3 and Ender-3 V3 Plus, and a separate one for the K2, K2 Plus and Creality Hi. Creality doesn't list either as fitting the other's printers.
  • Early K1 and K1 Max units differ. Creality's Unicorn listing says it also suits "the new version of K1/K1 MAX with integrated nozzle," and asks buyers to check which version they have. Creality sells a separate High Flow Nozzle Kit listed for the K1, K1 Max, Ender-3 V3 KE and CR-10 SE. Creality's store also lists a genuine E3D ObXidian High Flow nozzle assembly for the "K1 (2024)" and "K1 Max (2024)", K1C, K1 SE and Ender-3 V3 / V3 Plus, which confirms the split by year.

Check the K1C nozzle list, K1 Max nozzle list or Ender-3 V3 nozzle list and read the listing text for your version.

Which ones are interchangeable

Short answer: within a family, yes; across families, only where the table shows a shared format.

  • MK8 and V6 are not the same nozzle. Both are M6 × 1, so a V6 nozzle can physically thread into an MK8 block and the reverse. But MK8 has 5 mm of thread and V6 has 7.5 mm, and the hotends are designed around where the nozzle ends inside the block. Micro Swiss and Bondtech sell them as separate products with separate compatibility lists. Buy the format your hotend is listed for.
  • A Volcano nozzle does not belong in a V6 block. At 21 mm against roughly 12.5 mm, it can't sit in a V6 block the way it was designed to. Sellers list Volcano nozzles as not compatible with V6 blocks. Going Volcano means changing the heater block as well.
  • CHT is a geometry, not a format. The common mistake is assuming "CHT" fits everything. A Bondtech MK8 CHT fits MK8 hotends; a RepRap CHT fits V6 hotends; a Volcano CHT fits Volcano blocks; and the Prusa CHT nozzle fits only Nextruder printers. Bondtech's guidance that gains show up from 0.6 mm and up is worth reading before buying a 0.4 mm CHT for speed.
  • Revo, Prusa Nozzle and Unicorn are closed families. Each pairs the nozzle with its own heatbreak. None of them screws into a V6 or MK8 block, and V6 nozzles only go into a Nextruder through Prusa's adapter.
  • More flow needs more heat. A high-flow nozzle doesn't raise your hotend's heater power. Before you count on a bigger number, run your setup through the volumetric flow calculator.

Bambu Lab printers are their own case: each series uses its own hotend, and the nozzle comes with it. Our guide to Bambu Lab hotends covers which one fits which printer, and the A1 nozzle list shows what's listed for the A1.

How to tell which nozzle your printer has

  1. Check the hotend, not the printer name. An Ender-3 with a Micro Swiss or Revo upgrade no longer takes the stock nozzle.
  2. Look at what comes out. If the nozzle unscrews by itself from a block, it's MK8, V6 or Volcano. If a nozzle and tube come out together, it's Revo, Prusa Nozzle, Unicorn or a similar integrated unit.
  3. Measure a spare. About 13 mm overall with a short 5 mm thread suggests MK8. About 12.5 to 13 mm with 7.5 mm of thread suggests V6. Around 21 mm suggests Volcano.
  4. For Creality K1 and K1 Max, confirm the year. Creality ties several nozzle kits to the newer "integrated nozzle" version.
  5. Read the listing. Every fit on our nozzle pages is backed by the seller's own listing text naming the printer. "Listed as compatible" is what that means, not a guarantee.

Nozzle material is a separate choice from nozzle family: any of these formats can come in brass or hardened steel. If you print carbon fibre or glow filament, read which nozzle material abrasive filament needs.

FAQ

Does a V6 nozzle fit the Ender-3?

Not as a direct replacement on the stock hotend. The stock Ender-3 hotend takes MK8 nozzles, which Micro Swiss lists for the Ender 3 and Ender 3 V2. A V6 nozzle shares the M6 × 1 thread but has a longer threaded section. If you've fitted a V6-style hotend, then V6 nozzles are the right choice.

What's the difference between MK8 and V6 nozzles?

Thread length and the hotend they're built for. Micro Swiss and Bondtech list MK8 at 5 mm threaded, 13 mm overall, and V6/RepRap at 7.5 mm threaded and 12.5 to 13 mm overall.

Is a CHT nozzle better than a V6 nozzle?

They aren't alternatives. Bondtech makes CHT nozzles in V6 (RepRap) format, so a CHT nozzle can be a V6 nozzle. The difference is the multi-channel bore, which Bondtech says raises maximum flow, with meaningful gains from 0.6 mm nozzles and up.

Will Revo nozzles fit my V6 hotend?

No. E3D says Revo nozzles are not compatible with V6-style heater blocks. Revo Six is a whole hotend with the same height, diameter and mounting as a V6, so you'd replace the hotend rather than just the nozzle.

Do K1C Unicorn nozzles fit the K2 Plus?

Creality sells separate Unicorn kits: one for the K1C and Ender-3 V3 / V3 Plus, and one for the K2, K2 Plus and Creality Hi. Creality doesn't list either one for the other's printers, so buy the kit that names your printer.

Sources

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